Some aspects of dendrochronology in the Baltics

Alar Läänelaid

Institute of Geography, University of Tartu, Tartu, Estonia, e-mail: alar.laanelaid@ut.ee

There are lots of common features in dendrochronology in the three Baltic states – Estonia, Latvia and Lithuania: the same tree species used (Scots pine Pinus sylvestris, Norway spruce Picea abies, English oak Quercus robur), similar climate, and many common research topics. The tradition is strongest in Lithuania, where a tree-ring laboratory was established in early 1960-ies. Chronology development of pine, spruce and oak is carried out in all three states. At present the dated pine chronologies extend back to the 12th century in Estonia (with a gap) and Latvia and to the 11th century in Lithuania. Spruce chronologies have minor extension because of less findings and dating difficulties. Dated oak chronologies exist in Estonia (AD 1264-1600) and in Lithuania (AD 1202-1418). Prospective development directions of dendrochronology are more alike in Estonia and Latvia: prolonging the chronologies, dendrochronological dating for various tasks, dendroclimatology and -ecology. A common prospective research topic for Latvia and Lithuania is dendroprovenancing (historical timber trade from the Baltics). In Lithuania the prospective directions include genetical investigations of trees, stable isotopes, studies of diurnal and seasonal growth, and investigation of introduced tree species (e.g. Larix, Pseudotsuga). Several of these research topics like dendroprovenancing, genetical studies etc. require international co-operation within the Baltics and with other countries.

Reconstructing Summer North Atlantic Oscillation (SNAO) variability over the last centuries

Hans Linderholm¹, Chris Folland², David Fereday², Jim Hurrell³, Sarah Ineson², Jeff Knight² and Adam Scaife²

¹Earth Sciences Centre, Göteborg University, Göteborg, Sweden, e-mail: hansl@gvc.gu.se

²Hadley Centre, Met Office, Exeter, UK

³National Centre for Atmospheric Research, Boulder, Colorado, USA

Eigenvector analysis carried out over the annual cycle in the North Atlantic and Arctic region on seasonal NCEP mean sea level pressure data gives a set of dipole patterns including the familiar winter North Atlantic Oscillation. In summer, the scale of the EOF is smaller and its southern node stretches from near UK to Scandinavia rather than the Azores – Spain region seen in winter. Here, we use a new daily data set of pressure at mean sea level, EMSLP, created over 1850-2003. Its domain is limited to 70^oN at its northern-most latitude. An EOF analysis over 1881-2003 in summer recreates mainly the southern part of the full summer EOF node seen in NCEP data. Here we concentrate on July and August or “high summer” as the temporal variation of pressure patterns at this time is more similar than in June.

Regressions of the SNAO pattern (chosen to be the daily EOF pattern) with surface temperature and rainfall in high summer, show a strong influence of the southern node of the SNAO for a region stretching from the UK to Scandinavia. When the southern node has higher pressure (positive SNAO), warmth and dryness is seen. Also, the SNAO shows up strongly in cloudiness data. The SNAO varies strongly interannually but also interdecadally, particularly in the twentieth century. Relatively low SNAO values over 1920-1960 were followed by a sharp rise in the 1960s to 1970s with a relatively high level maintained until the 1990s. This period had several extreme UK summer droughts.  Regression analysis of the SNAO with sea surface temperature (SST) suggests that its interdecadal variations can be related to the Atlantic multidecadal oscillation (AMO), a periodic warming and cooling of the North Atlantic that has been associated with variations in the thermohaline circulation. Because the SNAO strongly affects temperature and rainfall in Scotland and Scandinavia, paleoclimate data based on tree rings have been used to reconstruct an index of the SNAO back to the eighteenth century with some skill, mainly on decadal time scales. The likely skill of the reconstructions and the evolution of SNAO over the last centuries is discussed.

Representative Mean Growth Behaviour of Forest Stands – Methodical Aspects from Dendrochronology and Forest Mensuration

Dr. Wolfgang Beck

Federal research Centre for Forestry and Forest Products, Institute for Forest Ecology and Forest Inventory, Eberswalde, Germany

e-mail: wbeck@bfh-inst7.fh-eberswalde.de

Building up tree ring index chronologies requires the calculation of a mean index value at each time step which represents the typical stand wide growth reaction and which enhances the common climate signal of the chronology. Mostly TUKEY’s biweight robust mean is used therefore. This method calculates a mean close to the median which includes this part of series which is close to the centre of the distribution and excludes the tail. Inclusion is done by a weighing function, values above a threshold are excluded. This procedure is applied time step by time step, but the crucial point is, that at each time step other series are included or excluded. So, the contributing weight of a single series may vary over time considerably.

The attempt proposed here acts on the assumption that each sample tree with its increment cores has to be seen as a representative of the whole stand. The growth courses of all single sample trees reflect the common system wide behaviour of the whole tree stand. Each single sample tree has the same weight to contribute to the system’s behaviour at each time step.

The procedure proposed here consists in the following steps:

• Reconstruction of the diameter growth course from ring width series; determination of a diameter at the beginning of the course if pith is failed when core was taken; standardisation of the growth course to DBH without bark

• Transformation of the absolute diameter series to relative series within a range between 0 and 1.

• Calculation of the mean relative diameter growth course; evaluation of similarity or dissimilarity of the single growth courses; exclusion of single series from chronology if their growth dynamics diverge from common mean growth course over time profoundly.

• Calculation of the mean basal area weighted diameter without bark of all included sample trees.

• Back-transformation of the mean relative diameter growth series into a mean absolute diameter growth course by multiplication with mean diameter.

• Back-transformation of mean diameter growth series into mean ring width series.

• Calculation of mean tree ring index series by prewhitening (AR(1)-modelling) and elimination of persisting trend portions by spline approximation

This procedure is seen to be better qualified to express the mean common chronology signal, because all included single series contribute in the same size at all time steps of the series.

Additionally, calculated mean diameter growth trend and its transformation to time series of mean basal area increment can be used for a detailed growth behaviour analysis. Results of analysis of climate effects on tree growth using mean tree ring index chronologies can also be transformed till to mean diameter growth course, because all calculation steps can be tracked back. Both, mean tree ring index chronology and mean diameter growth course are branches of a consistent system.

Wood anatomical analysis of fire-scarred chestnut in southern Switzerland

Erica Bigio, Holger Gärtner & Marco Conedera

Swiss Federal Research Institute WSL, Zürcherstrasse 111, Birmensdorf, Switzerland

e-mail: ericabigio@hotmail.com

In April of 1997, a medium to high intensity surface fire burned in a chestnut coppice in southern Switzerland, leaving many trees scarred at the stem base by the passing fire. The aim of the research is to use wood anatomical methods to identify features within the cell structures related to heat and fire injury.  For this, focus is set on analyzing trees where the fire had partially killed the cambium, creating a fire scar, along with trees where the cambium may have been affected by a sub-lethal level of heat. Cross-sectional samples of adjacent fire-scarred and non-scarred shoots were taken from the same stool, along with samples of reference trees from outside of the burned area.  Samples were sanded and analyzed for macroscropic changes in growth preceding and following the event year of 1997.  Thin sections were made of the 1997 growth ring from the fire-scarred cross sections on the opposite side from the open scar face, from the uphill and downhill sides of the intact cross sections, and also from the reference trees.

First results show that the cell structures in the 1997 ring, which were visually compared among all three sets of samples, but did not show obvious differences in growth away from scar region. However, at the outermost borders of the scar region, in the immediate vicinity of the killed cambium, surviving cambium initials kept on producing fibers and even vessels without beginning to overgrow the wound. After producing several cell layers, a portion of this area stops developing and is then covered by cell layers starting to overgrow the wound. The onset of the overgrowth is variable, often even starts in 1998.  Ongoing analysis will concentrate on the scar region as well as further analyzing cell structures using an image analysis program.

Influence of tree and stand index thresholds on the number of pointer years

Szymon Bijak

Department of Dendrometry and Forest Productivity, Faculty of Forestry, Warsaw Agriculture University, Nowoursynowska 159 bud. 34, 02-787 Warszawa, Poland

e-mail: Szymon.Bijak@wl.sggw.pl

Determination of the pointer years is very important task in dendrochronological analysis. However, there are so many different procedures of that process that any comparisons and cross-analyses are difficult. There are also specific criteria to assess if the year is pointer or not. Moreover, literature review, revealing the vast range of applied values, gives no clue which of them to utilise.

We applied the ‘normalisation in the moving window’ method to determine pointer years for the period of 1953-2002 in two sets of spruce and oak tree-rings data. Different tree and stand index thresholds were used, which allowed determining formulae describing relationships between index values and number of pointer years, and between both indices. We derived minimum values of the thresholds necessary to obtain single pointer year or number of pointer years equal to 5, 10 and 20% of the total number of years in analysed period. Results from the ‘normalisation’ method were then compared to the output of subjective visual analysis of the tree-ring series.

For both of analysed sets, it turned out that, no matter which pointer year level we applied, tree index remains constant when stand index equals less then 0,5. This stands on the contrary to the results of visual examination, which gave constantly decreasing curve.

Dendroecology of neolithic timber using dendrotypology, growth-patterns and stand-dynamics

Niels Bleichner

Römisch-Germanisches Zentralmuseum Mainz, Ernst-Ludwig Platz 2, 55116 Mainz, Germany

e-mail: bleicher@holzanalyse.de

A large number of archaeological samples from upper-swabian neolithic timber have been analysed dendrochronologically. In order to reconstruct human activities in the landscape a threefold approach was used: First the samples were classified into ecological groups using dendrotypology. Analysis of stand-dynamics allowed to interpret these groups in terms of what kind of stands they came from and what kind of disturbance-regimes governed these stands. Lastly it was tried to find analogies for the different kinds of patterns observable in the samples both on the level of tree-ring series and anatomy. In doing so different categories of patterns were defined for the palaeoecological approach. Among these are ring patterns, growth patterns, complex patterns and stand-dynamic patterns.

These analyses allowed to reconstruct cyclic human activities in and around the Federsee-basin of the time around 3300 BC and 2890 BC. Hitherto unknown systems of prehistoric forest-use were detected. The dating of the settlements gave the opportunity also to reconstruct the rhythms of settlement-dynamics as well as succession-phases on former economic areas. These results can be directly compared with local pollen-diagrams. Thus dendrochronology can be used to help interpreting pollen-data leading to a more comprehensive understanding of processes in the landscape and their traces in our proxies.

ENSO and NAO impacts on Pinus pinaster Ait. growth in Spanish forest

Stella Bogino^1,2; Felipe Bravo¹

¹ Departamento de Producción Vegetal y Recursos Forestales. Universidad de Valladolid, Avda. de Madrid 44. 34004 Palencia. Spain. TE. 34 979108427 sbogino@pvs.uva.es

²Departamento de Ciencias Agropecuarias. Facultad de Ingeniería y Ciencias Económico-Sociales. Universidad Nacional de San Luis. Argentina.

The impact of NAO and ENSO on radial growth of maritime pine (Pinus pinaster Ait.) had been analysed in Spaniard woodlands using dendroclimatological techniques. Nine residual chronologies across the natural distribution area of the species were built. Statistic indexes that describe the chronologies suggested a strong association between growth of maritime pine and causal environmental factors. Growth response to NAO and ENSO atmospheric indexes were calculated to the common period 1948 – 2005. Results showed a positive significant correlation along all the sampling sites with ENSO index, whereas NAO index effect changed from positive to negative according to the sampling site. Although there was not a common response to NAO index along all the analysed places the results were consistent with previous meteorological studies made in Spain that consider: that NAO index has a clear relationship with climatic conditions in Europe but this general association could not be applied to the Iberian Peninsula where the topography and the Mediterranean sea might strongly affect NAO behaviour. Even though future ENSO behaviour is still unknown these results emphasise both the impact of this atmospheric index on ecosystems locate too far away from centre pressures that control it and its importance as the major factor that control climatic conditions in the world.

The dendrochronology of archeological oak found in old town of Klaipeda

Mindaugas Brazauskas

Klaipeda University, Tilzes 13, Klaipeda, Lithuania

e-mail: vmbrazauskai@takas.lt

Dendrochronological dating of archaeological oak founds in Klaipeda have several aspects of interest and investigation. First one is oriented in straight interest of archaeological dating method, in dating of archaeological cultural layers and structures.

Second one is exceptional research based on dendrochronological questions and dendro provenance. There we have mainly oak dating problems with master chronologies and dendro provenance. At the moment all archaeological oak samples are divided into two groups. The first one consists of oak timber used in archaeological structures as building material. Mainly there is oak timber of local provenance. The second groups are the parts of barrels distributed in cultural layers of Klaipeda from 15^th until 19^th. The oak planks from barrels more indicates not local origin and been observed as objects for dendro provenance studies.

The compiled dendro scales from Klaipeda are open for dendrochronologists have interest in.

Life at the edge: resolving the climatological sensitivity of sub alpine snow gum

Matthew Brookhouse

The Australian National University, 48 Linneaus Way, 0200 Canberra, Australia

e-mail: matthew.brookhouse@anu.edu.au

Dendroclimatological studies usually investigate the relationship between tree ring characteristics and the two climate parameters – precipitation and temperature. While these are the climate factors of most interest to humans, they may not be the most important in determining inter-annual variation in tree growth and, hence, tree ring formation. We examined the climate sensitivity of tree-ring width chronologies from Eucalyptus pauciflora Sieb. ex Spreng from three elevation classes. Based upon the principle that climate sensitivity increases with proximity to the limits of tree growth, we hypothesised that the sensitivity of E. pauciflora tree-ring series would increase with elevation. Consistent with our hypothesis we found an increase in chronology statistics with elevation. We also found that ring width in each chronology correlated negatively with mean maximum air temperature during the preceding winter positively with maximum air temperature during the growing season. However, we did not observe an increase in sensitivity to temperature with increasing elevation. A highly significant positive correlation between each chronology and net radiation during summer appears to explain the response to summer temperature and precipitation. Rotated principal components analysis revealed greater sensitivity to inter-annual variation in net radiation at higher elevation. These results appear to have significant implications for dendroclimatological studies of eucalypts.

Application of multivariate cross-dating to historical timbers with less than 50 tree rings

C.T. Bues, B. Günther, J. König

Dresden University of Technology, Institute for Forest Utilization and Forest Technology, Chair for Forest Utilization, Pienner Straße 19, D-01737 Tharandt, Germany

e-mail: bues@forst-tu.dresden.de

During 2004 TRACE conference a new dating method for wood samples from spruce trees with less than 50 tree rings were presented. The so called “multivariate dating method” uses 10 different tree ring characteristics derived from X-ray images applying X-ray-densitometry. In a parallel running cross-correlation over a special developed standard chronology for spruce wood now true dating results can be achieved for small wood samples using a new TRA-software.

In the meantime the multivariate dating method was carried out for different cases to date historical spruce samples with e.g. 24, 32 or 35 tree-rings. Interesting examples from the practice of the master builder of the cathedral Meißen, Mr. G. Donath (on roof framings of the cathedral and the castle “Albrechtsburg” at Meißen) and in addition the results of smaller Spruce samples from the Cistercian monastery "Altzella" at Nossen will be presented. The conditions for a successful application of the new dating method will be described. It will be demonstrated, how different the dating results can be, using the traditional univariate dating method - only based on tree-ring width - in comparison to the multivariate dating method using the 10 different tree-ring parameters. It will be shown that the new method brings reliable results. First approaches will be discussed to bring the multivariate method to a level, were the dating of single samples with less than 50 tree rings can also be realized.

Eight centuries of Pyrenees summer temperatures from tree-ring density

Ulf Büntgen¹, David C. Frank¹, Håkan Grudd², and Jan Esper¹

1Swiss Federal Research Institute WSL, Dendro Sciences Unit, Zürcherstrasse 111, 8903 Birmensdorf, Switzerland

2 Dept. of Physical Geography and Quaternary Geology, University of Stockholm, Sweden and Abisko Scientific Research Station, The Royal Swedish Academy of Science

e-mail: buentgen@wsl.ch

May-September maximum temperatures of the Spanish Pyrenees are reconstructed for AD 1260-2005 using 261 density measurement series from a combination of living and dry-dead timberline trees. Application of the regional curve standardization method for tree-ring detrending allowed the preservation of low frequency temperature variability. The new record correlates at 0.53 (0.68 in the higher frequency domain) with temperatures over 1944-2005 calibration period. Reconstructed warm summers in the 14-15th and 20th century are separated by a prolonged cooling from ~1450-1850. Six of the ten warmest decades fall within the 20th century, with the remaining four between 1360-1440.

Comparison with new density-based summer temperature reconstructions from the Swiss Alps (Valais; AD 755-2004) and northern Sweden (Torneträsk; AD 500-2003) shows decadal to longer-term similarity between the Pyrenees and Alps, but no coherence with northern Sweden. Spatial field analyses using proxy and instrumental data support the regional differentiation of the three records. While 20th century warmth is evident in the Alps and Pyrenees, recent temperatures in Scandinavia are relatively cold in comparison to earlier warmth centered ~1000, 1400, and 1750. Cold periods during the second half of the 15th century, between ~1600-1700, and ~1820 are coherent between these regional-scale reconstructions and records representing larger areas of the Northern Hemisphere. However, while coldest summers in the Alps and Pyrenees are in-phase with the Maunder and Dalton solar minima, lowest temperatures in Scandinavia occur at the onset of the 20th century.

Blue Intensity in Pinus sylvestris: application, validation and climatic sensitivity of a new palaeoclimate proxy for tree ring research

Rochelle Campbell

Swansea University, School of Society and Environment, Geography Department, Singleton Park, SA2 8PP Swansea, United Kingdom

e-mail: 371431@swansea.ac.uk

Minimum blue intensity measurements of resin-extracted Pinus sylvestris samples, are shown to provide a robust and reliable surrogate for maximum latewood density.  Blue intensity data from fifteen trees, are reported relative to a standard blue-scale in a manner similar to grey-scale calibration in X-ray densitometry.  The resulting time series are highly correlated with X-ray densitometry data generated from the same samples and preserve a high level of signal strength.  The sensitivity to summer climate variables is similar to that identified in the relative density record, demonstrating that minimum blue intensity can also be used for the study of climate change.

Archaeological site of Dolmen de la Font dels Coms (Llavorsí, Pallars Sobirà, Spain). Charcoal analysis for human impact and dendroecological interpretation

Mireia Celma Martínez

Prehistory Department-Archaeobotany Laboratory, Universitat Autònoma de Barcelona, Edifici B  Campus de la UAB,  P.C.: 08913 Bellaterra (Cerdanyola del Vallés, Spain)

e-mail: mireia_celma@hotmail.com

Dolmen de la Font dels Coms is located at the top of  Vall de Baiasca at 1850 m altitude. The site was dug in 2003-04 and showed a repeated ocupation from prehistoric to roman times. Dolmenic construction was reused between third century BC to first century AC as an iron kiln.

This historical high-altitude iron kiln constitutes the site as a perfect example for studying human explotaition of raw materials. Analysis of charcoal samples are a conjunction between human raw material selection and ecological growth conditions. The object of analysis is determine species (used as combustible) and to obtain different data collection from anatomical features for growth-stress interpretation and attempt to extrapolate it to human activities.

Thanks to Parc Natural de l’Alt Pirineu (Alt Urgell-Pallars Sobirà, Catalonia, Spain), Ecomuseu de les Valls d’Àneu (Esterri d’Àneu, Catalonia, Spain) and Prehistory Department of Universitat Autònoma de Barcelona (Catalonia, Spain).

El Niño Southern Oscillation Signal in World Highest Elevation Tree-Ring Chronologies from the Altiplano Plateau at 4,600 m a.s.l.

D.A. Christie¹, A. Lara¹, J.A. Barichivich¹, R. Villalba², M.S. Morales² & E.A. Cuq¹

¹Laboratorio de Dendrocronología, Facultad de Ciencias Forestales, Universidad Austral de Chile, Valdivia, Chile

²Departamento de Dendrocronología e Historia Ambiental, IANIGLA, Mendoza, Argentina.

e-mail: duncan@sendadarwin.cl

El Niño-Southern Oscillation (ENSO) is the largest source of inter-annual variability operating in the earth's climate system, and is associated with extreme weather conditions having large social, ecological and economic impacts.

Several tree-rings records have been utilized to reconstruct past ENSO variability but none of them comes from South America. On the Altiplano plateau in the central Andes are located the world highest elevation forest composed by Polylepis tarapacana trees 4,000-5,000 m a.s.l. We use two tree-ring chronologies in order to analyze the regional climate and ENSO influences on P. tarapacana growth at the east and west Andean slopes on the Altiplano.

P. tarapacana growth has a strong common signal and a complex relation with summer temperature and precipitation. Ring-width has an inverse relation with temperature respect to precipitation. Temperature has a positive and negative influence on ring-width during current and previous summer, respectively. Tree-growth is positively correlated with spring-summer tropical Pacific SSTs, with a spatial pattern resembling to ENSO wedge. In general the El Niño (La Niña) events are well recorded in the chronologies, determining above (below) mean anomalies on tree-growth. P. tarapacana chronologies offer a good opportunity to future multi-proxy ENSO reconstructions.

Intra-annual variations of wood density of Picea abies [L.] Karst. at different altitudes of the Black Forest. Typified density profiles and the influence of weather conditions on wood density

Detlef Drosihn, Philipp Duncker and Heinrich Spiecker

Institute for Forest Growth, Albert-Ludwigs-Universität Freiburg. Tennenbacherstr. 4; D-79106 Freiburg i. Br./Germany

e-mail: dedrosi@arcor.de

The following study is an investigation about intra-annual wood density variations of Norway spruce (Picea abies) measured at three sites of different altitudes in the Black Forest/Germany, with an elevation from 400 to 1.200 metres above sea level. The objective of the study is to recognize certain weather conditions in the variation of the wood density.

Every site is represented by two trees and their stem discs in 1.3 metres height. The variation of wood density is recorded by a method named High-Frequency-Densitometry which makes use of the dielectric characteristics of wood.

From the available data a typified intra-annual wood density profile can be produced which characterizes all sites likewise and besides it allows the statistic comparison with the data of individual years that differ significantly.

The investigation refers to the year 2001 which was unusually warm and wet and the year 2003 which was unusually warm and dry when compared to the long term average.

Sections of the typified wood density profile of both years differ significantly but only in the lowlands.

Since forest growth does not take place in a linear way it is also necessary to develop a time scale for an intra-annual wood density profile to be able to assign wood density variations to exactly dated weather conditions. By making use of chronological radial growth data which were measured using dendrometres at the same three sites and which are shown as diagrams, some reference points of time can be applied to the wood density diagrams. By doing so short term weather conditions can be understood in the wood density profile of every site. It shows that drought makes the density rising, precipitations however make it drop.

The result of the evaluation shows that form and dimensions of the wood density-variation is caused by the weather conditions at the different altitudes. Apart from that, the variation of the wood density occurs predominantly in the late wood section of the year ring. The level of wood density increases from the highlands to the lowlands.

Furthermore, the analysis of the phenomena of air temperature and precipitation shows that a change of wood density of trees at the highest site is stronger linked up with important changes of air temperature than with events of precipitation. This applies for the early wood section as well as for the late wood section.

At the medium elevation site the wood density is also influenced mainly by the weather phenomena of air temperature but the growing influence of precipitation is more pronounced by decreasing tree ring widths during long lasting periods of drought.

The trees in the lowland-site show a significant stronger reaction on precipitation than on air temperature for the late wood section.

Dendroecological studies on subfossil pine and oak from „Totes Moor“ near Hannover (Lower Saxony, Germany)

Eckstein, J; Leuschner, HH; Bauerochse, A

Albrecht-von-Haller Institute, Dep. of  Palynology and Climate Dynamics, Untere Karspuele 2, D-37073 Göttingen, Germany

e-mail: Jan.Eckstein@biologie.uni-goettingen.de

Most of the raised bogs in Germany are situated in the Lower Saxony part of the North German Lowlands, in a landscape that was moulded during the ice age. In many of these peatlands, remains of subfossil pine (Pinus sylvestris) forests can be found. In the past these pine forests hardly received any attention and dendrochronological investigations were focussed on bog oaks. However the fact that peatlands with pine are known as common stages of mire ecosystems provides the chance to use dendroecological reconstructions of peatlands to gain a better understanding of climate influence on bog ecosystems.

In the framework of an ongoing project, subfossil pine from peat extraction areas in Lower Saxony are investigated at Göttingen University. One of the main study sites ,“Totes Moor”, is situated about 25 km north-west of Hannover. First results of dendroecologigal investigation in this area are reported.

So far 309 specimens of bog pines were studied. One hundred seventy fife of these specimens represents 13 groups of different ages providing 13 floating chronologies, the longest with more than 400 years. Only one chronology of 19 bog pines was crossdated with the Lower Saxony bog oak master chronology to the period  4783-4559 B.C.

The 60 studied bog oaks from “Totes Moor” cover a period from 6200 to 4550 B.C. with only one minor gap.

Both bog pines and oaks show a pattern of clearly alternating populations with periods of increased germination and/or dying off. Synchronous changes in growth pattern and population dynamics indicate that contemporary “stress-events“ occurred in former wetland woods which are most likely linked to striking environmental changes.
In the case of the datable pines from “Totes Moor”, changes in growth pattern and population dynamics synchronize surprisingly well with those seen in oaks.

Long-term drought severity variations in Morocco

Jan Esper¹, David Frank¹, Ulf Büntgen¹, Anne Verstege¹, Jürg Luterbacher², Elena Xoplaki²

¹ Swiss Federal Research Institute WSL, 8903 Birmensdorf, Switzerland

² Institute of Geography, University of Bern, 3012 Bern, Switzerland

e-mail: esper@wsl.ch

Cedrus atlantica ring width data are used to reconstruct long-term changes in the Palmer Drought Severity Index (PDSI) in Morocco, North Africa, over the past 953 years. The reconstruction captures the dry conditions since the 1980s well and places this extreme event in a long-term context. PDSI values were above average for most of the 1450-1980 period letting the recent drought appear exceptional. Our results, however, also indicate that this pluvial second half of the last millennium was preceded by generally drier conditions back to 1049. These long-term changes from initially drier then pluvial and recent dry conditions are similar to PDSI trends reported from western N-America, and we suggest that they are related to long-term temperature changes, potentially teleconnected with ENSO variability and forced by solar irradiance changes.

Effects of various site ecological features on radial growth pattern in North Rhine-Westphalia

S. Fischer, B. Neuwirth, J. Löffler & M. Winiger

Institute of Geography, University of Bonn, Meckenheimer Allee 166, 53115 Bonn, Germany

e-mail: fischer@giub.uni-bonn.de

Dendroecological network analyses are appropriate and often used approaches to investigate climate/growth relations and their spatial variabilities in larger regions. Although tree-ring sites in midlatitudinal areas will be included more and more in such networks there is a shortage of data leading to a lack of knowledge concerning the complexity of climate/growth response for lowlands and low mountain regions.

The present study, which is included in a running PhD project, supplements the dendroecological network. Therefore tree samples were taken in North Rhine-Westphalia and in surrounding regions including both, lowlands and low mountain ranges. An already existent network of oaks will be completed with data of other important tree species like Fagus sylvatica, Quercus robur, Quercus petraea, Picea abies, Pinus sylvestris and Acer pseudoplatanus L. to a multi species data set.

More than 60 dendrochronological sites, which are situated in heights ranging from 100 to 750 m a. s. l. and in different expositions and inclinations, represent a great diversity of site ecological attributes. Detailed information like soil type or vegetation type have been elevated for special forest ecological test areas in the framework of the biomonitoring of the LÖBF.

To investigate climate/growth relations single year analyses (according to Cropper) and time series analyses (linear correlations) have been made, separated in interannual and decadal variations. As a basis for these investigations a grouping of sites with similar growth behaviour (anomalies) will take place.

The talk presents the groups basing on similar growth anomalies, their dendroecological interpretations taking into consideration the biomonitoring data and the corresponding climate/growth relations. Finally all the results will be combined to generate growth patterns in North Rhine-Westphalia  responding to homogeneous effects of site ecological features.

Growth variations of oaks under different climatic and environmental conditions in low mountain ranges (Germany)

D. Friedrichs, B. Neuwirth, J. Löffler, M. Winiger

Department of Geography, University of Bonn, Germany

e-mail: d.friedrichs@geographie.uni-bonn.de

Tree-ring growth is influenced by different climatic and environmental factors. At the boundary of a species range, the most limiting climate element determines tree-growth, whereas the influence on tree-growth in low mountain ranges is more complex. To investigate the important elements on tree-growth, ecological studies can be carried out using site analysis, transects or network analysis. By utilising the same statistical procedures for all sites in a network analysis, e.g. climate-growth relationships, of different sites can be compared. In several transect and network analyses groups are calculated on the base of tree-growth in order to detect sites with similar growth patterns. These groupings are often used to identify ecologically separated units, e.g. elevation zones (Wilson and Hopfmueller, 2001).

In this study a newly established tree-ring network is presented. Groupings of 52 oak sites are calculated, using two grouping methods: i) the hierarchical cluster analysis and ii) the principal component analysis. The results of these groupings are compared, looking for similarities and differences. In addition, the hierarchical cluster analysis was applied, in order to group the sites in three different time periods. Calculating different time periods, we investigate the temporal stability of the groups. Finally, the spatial distribution of the groups within the research area is described and suggestions for the ecological reasons of this distribution are discussed.

Wilson, RJS., Hopfmueller, M., 2001. Dendrochronological investigations of Norway spruce along an elevational transect in the Bavarian Forest, Germany. Dendrochronologia 19, 67-79.

Traumatic rows of resin ducts - A valuable parameter for dating events in Geomorphology?

Holger Gärtner¹ & Ingo Heinrich²

¹ Swiss Federal Research Institute WSL, Dendro Sciences Unit, 8903 Birmensdorf, Switzerland, e-mail: holger.gaertner@wsl.ch

² Research Center Jülich, ICG-V, Wilhelm-Johnen-Straße, 52425 Jülich, Germany

Dating geomorphic processes based on the analysis of growth anomalies occurring in disturbed trees is an established method in Geomorphology. The most common anomaly related to mechanical stresses is the onset of reaction wood and resulting eccentricities in the annual rings of affected trees. These stresses can also cause abrupt growth suppression depending on their intensity. These growth anomalies are related to various stresses and they have frequently been used to reconstruct processes such as debris flows, rock fall, landslides, avalanches or creeping slopes. Although the presence of these growth anomalies has often been used, their timing of formation is a field of special interest rarely addressed in Dendrogeomorphology.

This is in particular true for traumatic resin ducts for which it is still not known when and to what extend they occur within the annual rings of a naturally grown tree. Reliable dendro-publications always regard traumatic resin ducts as indicators for mechanical, insect-related or other environmental disturbances describing them as late effects to environmental stresses, not as immediate reactions.

Various experiments focussing on the effects of insects or fungi and combinations of both on the development of traumatic resin ducts have been conducted in the last decades. However, there is still no proof for their immediate formation in the annual tree ring after wounding in naturally grown conifers. Additionally, only sparse information exists on their spatial distribution around the wound or within the respective annual ring of a mature conifer.

For the study presented, wounding experiments have been conducted (i) before the beginning of the vegetation period and (ii) after the end of the vegetation period on two naturally grown conifer species, European Larch (Larix decidua Mill.) and Norway spruce (Picea abies (L.) Karst.).

The experiments revealed that traumatic resin ducts show a high variability regarding their timing and spatial spread within tree rings. Spruce trees did not show immediate occurrences of traumatic resin ducts after wounding. Depending on their distance to the wound a delay of up to 10 months referred to the time of treatment was observed. Wounded larch trees did show immediate occurrence of traumatic resin ducts only in direct vicinity to the wound. Farther from the wound, their formation was delayed more and more and their occurrence was shifted towards the latewood of the respective ring.

In conclusion, traumatic rows of resin ducts cannot be used for accurately dating mechanical disturbances, especially not when working with cores, and therefore, they should be treated carefully only as what they are, stress responses, more or less delayed in time, to various forms of environmental impacts.

Seasonal dynamics of wood formation in Norway spruce during 2002-2004

Jožica Gričar^1*, Primož Oven², Tom Levanič¹

¹Slovenian Forestry Institute, Večna pot 2, SI-1000 Ljubljana, Slovenia

²University of Ljubljana, Biotechnical Faculty, Department of Wood Science and Technology,

Rožna dolina, Cesta VIII/34, SI-1000 Ljubljana, Slovenia

*e-mail: jozica.gricar@gozdis.si

Radial growth of tree species is sensitive to environmental conditions determining onset, rate and cessation of individual phases of xylogenesis. Seasonal dynamics of cambial activity and cell differentiation of tree species differs among years and sites. Length of the growing period and rate of the cambial cell divisions determine widths of the xylem increments. We studied the seasonal dynamics of wood formation in Norway spruce (Picea abies Karst.) in Slovenia during 2002-2004. Experiments using pinning technique were performed on 5 adult Norway spruce trees growing at Alpine site Pokljuka (Pok-elevation 1250 m) and 5 trees at lowland plantation Sorsko polje (SorP-elevation 350 m) at weekly intervals. The xylem increment was determined by investigation of permanent transverse sections stained with safranin and astra blue using a light microscope and an image analysis system. Since the xylem increment realized by the time of wounding could be interpreted as a number of cells or as measured widths, we used both approaches and then compared the results. Number of cells reflects the cambial productivity; meanwhile measured widths include also the information on the extent of the radial expansion of newly formed tracheids. However, in cases of crushed or compressed developing tissues, measured values are not reliable. We used Gompertz function for description of the radial growth of the trees at each site in 2002-2004. The pinning method uses the ability of the cambium and its youngest derivatives to respond to a minute mechanical injury without affecting the physiological integrity of a tree. Pin insertion into the cambium causes minute wound reactions, which define the increment reached from the time of pinning. The cambial activity occurred from end-April till July-August in trees at SorP and from second part of May till mid-August in trees at Pok. Greater differences in the onset of the cambial activity among years were observed in trees at Pok and just the opposite in trees at SorP in the case of cessation of the cell divisions. The duration of the cambial activity among years varied from 77-119 weeks at SorP and 70-84 weeks at Pok. The period of the maximal cell production was estimated to 140-162 day of the year at SorP and 162-180 day of the year at Pok. The differences in the widths of the xylem growth rings among years were greatest at SorP (37-62 cells or 1.06-1.73 mm) comparing to Pok (36-45 cells or 1.26-1.42 mm). Comparison of the Gompertz function coefficients between the number of cells and the measured widths of the xylem increment revealed stiffer curves in the case of the measurements which could be explained by higher contribution of the wider early wood tracheids formed in the first part of the growing season to the final widths of the xylem growth rings than the narrower late wood cells.

Dendrogeomorphological analysis of a landslide area near Buck’s Mills, England

Roman Gut^{1, 2}, Holger Gärtner² & Vanessa Winchester³

¹ Institute of Geography – University of Zürich

² Swiss Federal Research Institute WSL

³ Laboratory of Dendrogeomorphology, University of Oxford

e-mail: r_gut@cevi.ch

Dendrogeomorphology allows dendrochronological techniques to be applied for the reconstruction of slope movements. The activity of slow mass movements along the coast of Southeast England was reconstructed by analyzing eccentricities and abrupt growth changes in 42 oak trees (Quercus petraea). Leaning trees at the study site near Buck’s Mills (Devon, UK) indicate unstable ground conditions. Growth anomalies, such as eccentric growth between two opposing radii, can therefore be used to date event years. To further analyze the growth characteristics, a local reference chronology was built, dating back to AD 1882. A geomorphological map provided an overview of the study area and enabled the interpretation of the slope movements according to the location of the samples with the dated event years. In total, a large number of certain (62) and possible (108) event years were identified in the 43 sample pairs. Furthermore, results show that the slope is not moving as a solid block, but in separate units. These units show individual movement patterns, which are linked in some cases.

The study area could be divided in six sub-areas showing stable as well as unstable zones at various times. Recurrent movements at the upper part of the slope over the years impose pressure upon a bulge downslope. Two sudden movements of a rocky slab just underneath the bulge could be dated to the years 1924 and 1943. The area on the uphill side of the bulge is still in state of flux. Therefore, the bulge marks a potential starting zone for a bigger landslide. The technique used enabled to reconstruct the landslide activity along on the North Devon coast at a high temporal and spatial resolution.

Stable isotopes C, H and O in tree rings as a tool for climate reconstruction

Sławomira Pawełczyk¹, Anna Pazdur¹, Tatjana Boettger², Marika Haupt ², Marek Krąpiec³, Elżbieta Krąpiec-Szychowska³

¹Department of Radioisotopes, Institute of Physics, Silesian University of Technology, Krzywoustego 2, 44-100 Gliwice

²UFZ-Umweltforschungszentrum Leipzig-Halle GmbH, Sektion Hydrogeologie, AG Paläoklimatologie; Theodor-Lieser-Strasse 4, 06120 Halle/Saale, Germany

³Dendrochronological Laboratory, AGH University of Science and Technology, Mickiewicza 30, 30-059 Cracow

For the reconstruction of past climatic changes can be used tree rings widths, maximum late wood density and other parameters as stable isotopic composition in tree rings.

Investigations of stable isotopic C, H, and O composition in a-cellulose extracted from tree rings of pines (Pinus sylvestris L.) growing in the ecologically clean Suwałki Region (54°06 'N, 22°57'E), North Eastern part of Poland were undertaken. Climatically, the Suwałki region substantially differs from other regions of Poland. It is the coldest part of Poland apart from mountains.

Isotope records (d¹³C, d¹⁸O, d²H) cover the period 1600-2003. Those measurements constituted a part of more complex investigations of stable isotopic composition in tree rings for last 400 years in the frame of European project ISONET.

Meteorological data used for the investigation was obtained from the meteorological observatory in Suwałki (54°07’N, 22°58’E). The meteorological data set starting from 1931.

Relations between d¹³C, d¹⁸O, d²H in tree ring a-cellulose and meteorological data (temperature and precipitation) demonstrate that precipitation influences the stable isotopic carbon, oxygen and hydrogen ratios to a lower extend than temperature. July-August is the period with the stronger influence on stable isotope composition of carbon, oxygen and hydrogen, and therefore d¹³C, d¹⁸O, d²H can be regarded as indicators of summer climate change. In case of correlation coefficients due to temperature the highest correlation coefficient exists for hydrogen (r=0.57, n=73, p<0.001). For the combined periods (several months) higher correlation coefficients than for one month have been obtained.

On the basis of d¹³C, d¹⁸O, d²H values in tree ring a-cellulose and relations between isotopic composition and meteorological data reconstructions of the temperature for the period 1600-1930 were performed. For those reconstructions inverse calibration and classical calibration were used.

Stable isotopes in tree rings: climate and human activity in the last 400 years, Poland

Anna Pazdur ¹, Slawomira Pawelczyk¹, Natalia Piotrowska¹, Andrzej Rakowski¹, Malgorzata Szczepanek ¹, Tatjana Boettger ², Marika Haupt ², Stanislaw Halas³, Marek Krapiec ⁴, Elżbieta Szychowska – Krapiec⁴ and  Nakamura Toshio⁵

¹Department of Radioisotopes, Silesian University of Technology, Gliwice, Poland

²UFZ-Umweltforschungszentrum Leipzig-Halle GmbH, AG Palaeoklimatologie, Germany

³ Mass Spectrometry Laboratory, Maria Curie-Sklodowska University,  Lublin, Poland 

⁴ Dendrochronological Laboratory, AGH University of Science  and Technology, Cracow, Poland 
⁵Nagoya University, Centre for Chronological Research, Nagoya, Japan 

The light stable isotopes composition (δ²H, δ¹³C and δ¹⁸O values) in the annual tree rings (especially in pine and oak from moderate climate zone) are sensitive indicators of climate change (temperature, precipitation and sunshine) and also the anthropogenic influence. Δ¹⁴C in tree rings of the last 150 years records the significant Suess effect, reflected also in δ¹³C of the annual tree rings of pine collected from the east-northern part of Poland. 

The studies of climate change by stable isotope analysis were continued as the investigation of alpha cellulose extracted from the annual tree rings of pine collected from east-northern part of Poland and alpha-cellulose extracted from the annual tree rings and the late wood of oak collected from the southern part of Poland (Niepolomice Forest) within ISONET Project. 

Both regions vary in the climate condition - the influence of oceanic climate is significant in the northern region, and the continental climate in the southern region. The significant correlations between δ²H, δ¹³C and δ¹⁸O, widths tree rings and meteorological data were found. The correlation coefficients between δ²H, δ¹³C and δ¹⁸O and temperature, precipitation and sunshine were calculated on the basis of accessible meteorological data for sampling sites.

The measurements of ¹⁴C concentration was carried out in the whole wood from 2.5-years samples of pine (1860-2003) by LSC technique and independently with annual resolution in the alpha cellulose extracted from tree rings of pine (1960-2003) by AMS technique.

The records of δ¹³C in alpha cellulose from the tree rings of pine from the northern and southern part of Poland and the data of δ¹³C in the alpha cellulose from late wood of oak from the southern part of Poland over last 400 years are presented on the background of change of the climate indicators and Δ¹⁴C in atmosphere in the NH1 zone.

The magnitude regional Suess effect in Poland was estimated over the last several tens years period and then correlated with the comparative effect in Nagoya (central Japan, Arequipa (southern Peru) and the global changes of Δ¹⁴C in the NH1 zone.

500 years summer temperature variability in Eastern Carpathians inferred from stone pine (Pinus cembra) tree ring width

Ionel Popa, Olivier Bouriaud

Forest Research and Management Institute, Research Station for Norway Spruce Silviculture, Campulung Moldovenesc – Romania

e-mail: popa.ionel@suceava.astral.ro

The forest ecosystems from Carpathians region have a high dendrochronological potential but are still few studies about the climate-growth relationships, dendrochronological series or dendroclimatological reconstruction from Romanian territory (Schweingruber , 1985; Popa, 2004, 2006). The aim of this paper is to present the first long term temperature reconstruction for Eastern Carpathians. The study area is located in the Eastern Carpathians in Rodna Mountain National Park (47°32’N, 24°55’E), in a mixed timberline forest of stone pine (Pinus cembra) and Norway spruce (Picea abies), at 1750 m a.s.l.

In order to reconstruct the temperature dynamics in the last millennium we have compiled the longest tree rings chronology from Carpathians using samples from dead and living trees of stone pine (Pinus cembra). The LINTAB equipment and TSAP software were used for measuring the annual rings width with a precision of 0.01 mm, as well as for cross-dating the growth series by graphical comparison in a logarithmic scale. The results were checked for missing ring and dating error using the COFECHA software. The final dataset comprise 212 individual series from 129 trees (106 series from dead trees and 106 series from living trees). The growth series were standardized in order to eliminate the non-climatic signals and to maximize the climatic information from the individual series. To preserve the low frequencies in the tree ring chronologies the Regional curve standardization method (RCS) was used. The tree ring index was calculated as differences between individual growth series and regional growth curve. Instrumental climatic data for the study area are available only for the period 1961-2001 from Iezer Pietrosu weather station (47°36’N, 24°39’E 1785 m a.s.l.). In order to extend the instrumental data we use the temperature data from 0.5°x0.5° resolution CRU2.1 grid data-basis (Mitchell and Jones 2005). Both, grid and instrumental monthly temperature data were normalized to the reference period 1961-1990.

For temperature reconstruction was used the standard chronology obtained after RCS standardization. To avoid the loss of amplitude as result of regression we applied the scaling method of the mean chronology to the grid temperature anomalies (Esper et al. 2005).

The correlation analysis indicates a high and significant response to early summer temperature from current year (June-July). Also a positive reaction of tree growth is observed to the prior late autumn temperature (October – November). High temperature during the winter induces a negative response to cembra pine in the next growth year.

Periods with lower temperature are 1520-1620, 1660-1690, and 1725-1840 with a minimum in 1820 decade. High temperatures are reconstructed for 1700-1725 and mostly after 1840 with a clear increase in last 15 years.

Tree ring width and basic density of wood in different forest type

Eva Přemyslovská, Jarmila Šlezingerová, Libuše Gandelová

Mendel Agriculture and Forestry University, Department of Wood Science, Zemědělská 3, Brno 61300, Czech Republic

e-mail: premyslo@mendelu.cz

The aim of this work is to determinate an average tree ring width and basic density of Norway spruce (Picea abies /L./Karst.) growing in different vegetation forest zones. Norway spruce is the most important commercial specie in Czech republic and its portion of forest stands  is 53 %. The typological system of forest stands consists of horizontal (edaphic categories) and vertical (vegetation zones) zonation. There are statistically significant differences between the values of basic density and tree ring width according to vegetation zones and edaphic categories, however ,  statistically significant differences between the values of tree ring width can be observed only for 4^th- 6^th vegetation zones. Differences between values of basic density and tree ring width according to edaphic categories are statistically highly significant especially for 5^th and 6^th vegetation zones. We can observe close relation between tree ring width and basic density, with increasing basic density tree ring width decrease. In summary, results of this study provide evidence of the influence of growth conditions to wood formation.

The work on this project was supported by 6215648902 grant.

Temporal Stability of Climate-Isotope Relationships in Tree Rings of Oak and Pine  (Ticino, Switzerland)

C.E. Reynolds-Henne¹, R.T.W. Siegwolf¹, K. Treydte², J. Esper², S. Henne³, M. Saurer¹

¹ Paul Scherrer Institute, 5232 Villigen PSI, Switzerland

² Federal Research Institute WSL, 8903 Birmensdorf, Switzerland

³ Empa, Swiss Federal Laboratories for Materials Testing and Research, 8600 Dübendorf, Switzerland

e-mail: Christina.Reynolds@psi.ch

Reconstructions of climate based on stable isotopes in tree rings rely on the assumption that the relationship between climate and tree rings is stable over time.  However, studies of tree ring growth have shown age-dependent trends thought to result from either physiological changes or changes in the climate-growth relationship.  Isotope ratios in tree rings are affected by climate through photosynthesis (d¹³C) or uptake and use of water (d¹⁸O).  This study tested the consistency of the relationship between climate (temperature and precipitation amount) and tree ring cellulose d¹³C and d^8O for oak (Quercus petraea) and pine (Pinus sylvestris) for the period 1660-2000, south of the main crest of the Swiss Alps.  The comparison between tree rings and climate was made possible by long-term temperature and precipitation datasets based on monthly instrumental and proxy documentary data.  Overall five generalizations concerning climate-isotope relationships were identified, namely: (1) isotopic signals in tree rings reflect conditions of current growing season, (2) long-term temporal stability is observed for the d¹³C pine and temperature relationship only, (3) other correlations between tree rings and climate are mostly unstable and show step-wise shifts in correlation sign and intensity, over time, (4) the climate signal is oak is strongest in the 20^th century for both isotopes and (5) tree ring d¹³C responds to local climatic conditions while d¹⁸O reflects larger-scale atmospheric circulation processes.  These results provide a cautionary note for the calibration of long tree ring series with 20^th century relationships, at least for trees located at ecologically non-extreme sites.

Building of the oak standard chronology for the Czech Republic

Michal Rybníček¹, Tomáš Kyncl², Vladimír Gryc¹, Eva Přemyslovská¹, Hanuš Vavrčík¹

¹Mendel University of Agriculture and Forestry Brno, Faculty of Forestry and Wood Technology, Department of Wood Science, Zemědělská 3, 613 00 Brno, Czech Republic, michalryb@email.cz

²DendroLab Brno, Eliášova 37, 616 00 Brno, Czech Republic

The main aim of this work was to make up a standard oak chronology covering the area of the Czech Republic. The standard oak chronology, which was given the name CZGES 2005, is based on 194 average tree-ring series and covers the period 545 BC – 289 BC, 26 BC – 271 AD and 462 AD to 2004 AD. The new standard chronology has filled a gap in the network of the European standard oak chronologies to which it bears a considerable resemblance. Currently, the standard chronology enables dating of a vast majority of the oak wood found during the archaeological excavation and exploration works carried out in the historic buildings in the Czech Republic.

In addition to the aim stated above, the study was focused on the comparison between the detrended and undetrended standard chronologies. The differences established between the detrended and undetrended standard chronology have shown only too clearly how important it is to develop the detrended standard chronologies.

Finally, this study was concerned with stating the amount of the sapwood rings in the recent oaks. Surveying the number of the sapwood rings in the recent oaks, no significant differences were identified between the amount of the sapwood rings in the samples taken from the altitude 200 and 500 metres above the sea level. The overall results show that in South Moravia the amount of the sapwood rings in oak ranges from 5 to 21.

Acknowledgement

The project was prepared within a research plan of LDF MZLU in Brno, MSM 6215648902.

Growth responses to NAO along a Central European West-East Transect

Johannes Schultz, Burkhard Neuwirth, Jörg Löffler, Matthias Winiger

Institute of Geography, University of Bonn; Meckenheimer Allee 166, 53115 Bonn, Germany

E-mail: schultz@giub.uni-bonn.de

During the last decade, tree-ring widths has become an important and often used proxy for reconstructing large scale circulation conditions over the North Atlantic and Central Europe. These circulation conditions can be expressed by the North Atlantic Oscillation (NAO) and corresponding indices (NAOI). To improve the reconstruction of these indices and recognizing that tree growth in Central Europe is forced by changing influences of climate factor like temperature and precipitation, a better understanding of the NAO as forcing factor for radial growth is necessary, especially in low mountain ranges.

Therefore, the present study investigates the growth responses to NAO along a Central European multi-species transect from the Ardennes (Belgium) to the Ore Mountains (Czech Republic). The dendrochronological dataset consist of more than 400 dominant trees. All trees are older than 120 years and were sampled in 28 sites which represent the ecological and species specific spectrum of closed forests in the west-eastern transect. All tree ring-series were detrended in two ways, by calculating ratios between the raw series and their 5-year moving average and secondly by calculating ratios between the raw series and their 150-year splines. The resulting interannual and decadal growth anomalies were compared with three differently calculated indices of the NAO, representing the normalised surface pressure differences in the North Atlantic.

The three used NAOI and their various influences on tree-ring growth are compared. Basing on this, the modifications of the growth responses to NAO along the Central European west-east transect are discussed in consideration of the ecological gradients along this transect.

Application of electrospray ionization mass spectrometry in analysis of ancient wood components

Barbara Sensuła¹, Anna Pazdur¹, Peter Derrick²

¹ Department of Radioisotopes, Institute of Physics, Silesian University of Technology, Krzywoustego 2, 44-100 Gliwice, Poland

² Department of Chemistry, The University of Warwick, CV47AL, Coventry, UK

We presents the first results of study of glucose, enzymatic hydrolyzed from α- cellulose of tree rings, by using quadrupole ion trap mass spectrometer. The samples of ancient wood were collected from bell-supports of the free-standing Baroque belfry, situated nearby the Cistercian Abbey in Jedrzejow (Poland). In this research we investigate dynamics of enzyme reaction and we suspected interannual volatility in glucose concentration. The dendrological research and isotope ratios investigation was a part of ISONET project.

It is well known, that α-cellulose, extracted from tree rings, is a source of information for climatic reconstruction time scale. The information is contained in the chemical composition of wood, especially the isotope ratios, of the cellulose (δ²H, δ¹³C, δ ¹⁸O). The large molecular size and insolubility of carbohydrate polymers such as cellulose make it difficult to define chemically with precision. Hydrolysis is the principal mechanism by which enzymes degrade cellulose polymers. In this research the biodegradability of cellulose-based products was studied using a fungal Trichoderma reesei. Mass spectrometry analysis gave a chance to obtain more structural information on saccharides enzymatic hydrolyzed. The mass spectra of glucose were acquired by ESI-MS/MS in positive ion mode. The differences and annual volatility in abundant glucose ions has not been explained yet.

Firstly, we made mass spectrometry analysis of glucose hydrolyzed from α-cellulose extracted from ancient wood - Quercus robur L. (1631-1642 and 1726-1737AD). Secondly, we try to find out correlation between the annual fluctuation of glucose and the other saccharides concentration with the number of observed sunspots, isotope ratios and width of tree rings. Finally, the highest correlation was observed between interannual volatility of saccharides concentration and tree-ring width index (RWI).

This project was supported by Marie Curie Fellowship Scheme and British Council Young Scientists Program and  ISONET project.

Tree ring analysis in a damaged pine stand

Robert Tomusiak

Faculty of Forestry, Warsaw Agricultural University, Nowoursynowska 159/34, 02-776 Warsaw, Poland

e-mail: rtomusiak@wl.sggw.pl

One of the applications of dendrochronological methods is assessment of the influence of insect gradations on tree growth.

The objective of this paper was to examine hypothesis that Rhyacionia buoliana causes decrease in tree ring widths on breast height.

The attempt of verification of that hypothesis was carried out on the basis of material gathered in the Scotch Pine stand growing close to Warsaw. In this stand a lot of trees have visible sings of the damage caused by Rhyacionia buoliana.

Tree ring chronologies were elaborated for four groups of trees: damaged and undamaged from 1^st and 3^rd Kraft bio-social classes.

Tree ring analysis and comparison of the chronologies from different groups of trees did not reveal any explicit influence of Rhyacionia buoliana on radial growth of trees, except for higher value of coefficient of variation of tree ring widths in damaged trees from 3^rd Kraft class.

Signal strength and climate calibration of a European tree-ring isotope network

Kerstin Treydte

Swiss Federal Research Institute WSL, Zürcherstrasse 111, 8903 Birmensdorf, Switzerland

e-mail: treydte@wsl.ch

We present the first European network of d13C and d18O in tree rings, containing 23 sites from Finland to Morocco. Common climate signals are found over broad climatic-ecological ranges and in temperate regions with positive correlations to summer maximum temperatures and negative correlations to summer precipitation and Palmer Drought Severity Indices (PDSI) with no obvious species-specific differences. Since PDSI integrates temperature and precipitation, it seems to be most appropriate for climate reconstruction at least in the higher frequencies. Averaged 'European' ¥13C and ¥18O chronologies share high common variance in the year-to-year variations. Long-term variations, however, differ and might be biased by age trends and/or plant physiological response to increasing atmospheric pCO2. Spatial correlation tests using a combined ¥13C-¥18O chronology indicate that central European climate variability is well captured, whereas Scandinavia and the Mediterranean region currently are underrepresented. Future studies will therefore focus on the regionalization of the climate signals.

A tree-ring derived fire weather reconstruction and climatology for northern California and Oregon

Valerie Trouet, Alan H. Taylor, C.N. Skinner, and A.M. Carleton

Swiss Federal Research Institute WSL, Zürcherstrasse 111, 8903 Birmensdorf, Switzerland

e-mail: trouet@wsl.ch

Wildland forest fires pose a significant threat to life and property in the North American Mediterranean climate region of northern California and southern Oregon.  Fire managers rely on fire weather indices (e.g., Haines index) to estimate fire risk and fire severity.  A better understanding of the relation between synoptic-scale circulation patterns and surface fire weather conditions can contribute to refining the functional link between fire activity and climate variability.

This study aims at reconstructing interannual Haines index variability for northern California and southern Oregon.  The Haines Index combines a stability and a moisture component as a measure of wildfire growth potential and wildfire severity.  We used variation in annual tree ring widths to reconstruct annual variation in annual Haines Index values.  Four regional ITRDB tree-ring chronologies were selected in a stepwise linear regression procedure for the calibration period 1961-1996.  The tree ring model was verified based a leave-one-out scheme and the Haines Index was reconstructed over the full length of the tree ring chronologies (1637-1996).

The reconstructed Haines Index time series was then compared to independent, regional, fire-scar derived records of fire frequency and fire extent (1700-1900) and to independently reconstructed indices of atmospheric circulation patterns (SOI, PDOI).  Understanding the low-frequency (inter-annual to inter-decadal) variability in fire weather conditions can contribute to the development of longer-term and more precise forecasting schemes for fire risk.

Recent treeline dynamics in northernmost Sweden (Torneträsk): a multidisciplinary landscape approach

Rik Van Bogaert

Ghent University, Krijgslaan 281 S8, 9000 Gent, Belgium

e-mail: Rik.VanBogaert@UGent.be

This project aspires to contribute to the gap-filling at the landscape scale in northern treeline research. A multidisciplinary assessment will be handled. As in the present author’s opinion the treeline is controlled by both environmental and plant performance factors, disciplines such as geomorphology, ecology and climatology need to be geographically interrelated. The project aims to explore recent dynamics of the mountain birch treeline (Betula pubescens Ehrh. spp. tortuosa (Ledeb.) Nyman) at the Torneträsk area in northernmost Sweden. However, apart from detection, also characterization and causation of treeline dynamics will be sought for.  This is urgently needed since this is essential to refine vegetation models, using at present only parameters from disciplines such as biogeography and biochemistry.  Dendrochronology and remote sensing provide major tools in assessing the treeline issue. Dendro-climatology will reveal the sensitivity of mountain birch to the late twentieth century warming episode, whereas dendro-ecology and –geomorphology may clarify the importance of treeline rise inhibitors such as herbivory and geomorphologic events.

Dendrochronological investigation on historical English oak (Quercus robur L.) in Lithuania and Latvia: problems and potential

Adomas Vitas¹ , Māris Zunde²

¹Vytautas Magnus University Faculty of Nature Sciences Environmental Research Centre Group of Dendroclimatology and radiometrics, Ž.E. Žilibero 2, LT-46324 Kaunas, Lithuania, e-mail: a.vitas@gmf.vdu.lt

²Institute of Latvian History at the University of Latvia, Akadēmijas laukums 1, LV-1050 Rīga, Latvia, e-mail: zunde@lanet.lv

Although the study of oak tree rings has been widely used to obtain long-term millennial chronologies in Europe, dendrochronological study of oak in the Baltic States has so far produced very limited results. Subfossil oak wood has been found in both countries in the past, and in some cases also at the present day, in bogs and sandy riverbank deposits, but the number of wood samples obtained is very small.

In Lithuania, the findspots of subfossil oak wood are located mainly in the northern part of the country. Seven samples have been radiocarbon-dated, indicating that some of the oak trunks discovered here date from the period 3300–6100 BC.

The findspots of historical oak wood in the area of present-day Latvia are very widely dispersed. The oak trunks found at these sites cover the period approximately from 4000 or 5000 BC up to the first half of the 14th century AD. These have not been dendro-dated so far, mainly because there has not been sufficient interest or funding.

Dendro-dating has so far been undertaken on extensive collection of wood samples from the gravel pit at Smurgainiai (western Belarus). As a result, 10 floating chronologies have been obtained, covering periods of 84–902 years within the time interval from 5300–5000 BC up to about 1325 AD (A. Vitas, Eurodendro 2004). These chronologies might be used for absolute dating of historical oak trunks found in the Baltic area.

Of course, the main sources of archaeological and historical samples of English oak in the territory of the Baltic States are historic structures and buildings. Unfortunately, there is also very little oak wood preserved in standing structures from the Historical Era. In large measure, this can be explained in terms of the rapid reduction of oak forest during the 2^nd millennium AD. In the past, a considerable quantity of oak timber was also exported to Western Europe. A proportion of the structural timbers of oak recovered in the course of earlier archaeological excavation were not dendro-dated. However, although oak wood from the Historical Era is very rarely preserved, we now have the first successful dendro-dating results. So far, oak structural timbers from Vilnius Lower Castle have been dated and chronology covering 1202 - 1418 AD was compiled (R. Pukienė, Eurodendro 2005), and dating work is currently in progress on structural timbers from buildings in Klaipėda Old Town.

The chances are promising that the study of oak wood from buildings will permit us to compile chronologies by extending the series based on living oaks. Since the stocks of historical oak wood are gradually being lost, there is a pressing need for dendrochronological study of this material.

Detecting annual growth rythms from oxygen and carbon isotopes in tropical mountain rain forest trees in southern Ecuador

Peter von Schnakenburg¹, Achim Bräuning¹, Gerd Helle²

¹ Institute for Geography, University of Erlangen, e-mail: pvons@web.de

² Forschungszentrum Jülich

Dendroclimatologic investigations in temperate climate zones are commonly based on the tree-ring parameters ring width and maximum latewood density. While dendroclimatology contributed significantly to our knowledge of past climate variability in higher latitudes, only sparse information has been gained by dendroecological studies in tropical region so far. Due to the lack of pronounced climatic seasonality trees in the inner tropics usally do not form distinct tree rings and this often hampers tree-ring analyses using ring width. To derive information about past climate variability in the humid tropics, we applied a combination of different methodological approaches.

The location of our study site is in the leeward position of the eastern Andean mountain range in the Podocarpus National Park in southern Ecuador. Former investigations in this project showed that some tree species react on seasonal climate changes by forming visible density variations and growth boundaries. For this study we used the conifer Prumnopitys montana (Podocarpaceae) that shows visible density variations and potentially reaches high ages of several centuries.

High-frequency densitometry and the analyses of stable carbon and oxygen isotopes are used to gain information about growth rhythms and climate variability in the past. The calibration of the tree-ring data is accomplished with meteorological data from a nearby weather station and oxygen isotope measurements of rainfall.

The seasonal change in the prevailing wind direction causes a change of the dominant moisture source, which should be reflected by intra-annual variations of the δ¹⁸O-signal in the wood. On the other hand the δ¹⁸O-signal is influenced by the amount of rainfall (the higher the rainfall the more the δ¹⁸O-signal is diluted). In contrast, the intra-annual variations of δ¹³C reflect the seasonality of water availability. By using the δ¹³C-signal it ought to be possible to verify whether changes in δ¹⁸O depend on drought stress or on alterations of the atmospheric circulation.

High-frequency densitometric analysis are able to detect even small wood density variations which help to identify indistinct growth boundaries. A calibration of the density curves with the isotope signals shall finally enable a reconstruction of the past climate variability.

The reconstruction of spring precipitation variation from tree rings since AD 1550 from Northwestern Yunnan, China

Fan Zexin and Achim Bräuning

Insitute of Geography, University of Erlangen-Nürnberg, Kochstrasse 4/4, D-91054 Erlangen, Germany

e-mail: fanzexin@yahoo.com.cn

Tree rings play an important role in understanding past climatic change on the Tibetan Plateau.  Here we developed four ring-width chronologies of three species (Picea likiangensis, Tsuga dumosa, Abies ernestii) on the Baima snow mountain, NW Yunnan, China. Although the chronologies from difference species, significant correlations exist among all the chronologies (mean r=0.44), and the first principal component of the four chronologies accounts for 58% variance over their common period 1550-2005.  Correlation analyses showed that January, March and May precipitation have positive affecting on radial growth, which indicated that the growth is generally limited by spring moisture availability. Dry spring occurred during AD: AD 1590-1610, 1620-1660, 1700-1715, 1733-1743, 1790-1825, 1910-1925, 1960-1990; Excessive spring precipitation occurred during: AD1612-1623, 1687-1699, 1716-1732, 1744-1756, 1778-1790, 1825-1850, 1926-1960.

The impact of micro-site conditions on ring-width variations of the alpine dwarf shrub Empetrum hermaphroditum

Annette Bär ^1,2, Jörg Löffler ¹, Achim Bräuning ³

¹ Department of Geography, University of Bonn, Germany

² Department of Biology and Environmental Sciences, University of Oldenburg, Germany

³ Department of Geography, University of Erlangen-Nuremberg, Germany

e-mail: baer@giub.uni-bonn.de

Ring-width chronologies of the alpine dwarf shrub crowberry (Empetrum hermaphroditum) were analysed focussing on micro-topographic differences between the ridge, south-facing, and north-facing slope located in the Norwegian Mountains. We expected effects on ring-width formation since micro-topography is regarded to induce micro-climatic differences in high mountains e.g. temperature and snow melt variations. In addition, the prostrate growth of E. hermaphroditum may reflect these differences which are more pronounced near the surface.

Continuous time-series analysis reveals the major impact of temperature during the growing season (June to August) which is present in all micro-site chronologies. Pointer year analysis confirms the prominent low temperature signal for negative pointer years, whereas positive pointer years do not necessarily occur simultaneously with high temperature. As a consequence, in summery warm years with additional low precipitation positive pointer years are only found at the ridge and north-facing slope, but not at south-facing slopes where highest temperatures occur.

The study of vessel formation led to a more detailed view on the interaction of temperature and precipitation. An approx. 25 day delay in the growing season at the north-facing slope, owing to late snow melt does not have significantly impact on the percentage of vessel area compared to the ridge. While temperature controls the rate of vessel formation at the beginning, precipitation is more important in the middle of the growing season, especially at ridges without melt water supply.

Tree-ring analyses at a sporadic permafrost site below timberline, Bever Valley, Switzerland

Alexander Bast^1,2, Holger Gärtner¹, Isabelle Roer¹ & Christof Kneisel²

¹ Swiss Federal Research Institute WSL, Dendro Sciences Unit, 8903 Birmensdorf, Switzerland

² University of Würzburg, Department of Physical Geography, 97074 Würzburg, Germany

e-mail: a.bast@uni-wuerzburg.de

The study presented focuses on tree growth analysis at a north facing slope extending from 1800 to 1900 m a.s.l. in the Bever Valley (Bever, Switzerland), a tributary of the main valley Upper Engadine. BTS (bottom temperature of winter snow cover) and geoelectric measurements point to the existence of permafrost lenses at this site, which was also confirmed by one core drilling experiment in 2006.The slope is covered with a dense forest stand consisting of larch (Larix decidua Mill.) and Swiss stone pine (Pinus cembra ssp. sibirica). The trees do not show any morphological differences (e.g., dwarfing) to trees adjacent to the slope, not even to trees growing on the opposite south facing slope, where definitely no permafrost is present.

The aim of the study was (i) to investigate the possibility of detecting the presence of permafrost by analyzing ring-width variations in larch related to a local reference chronology established on the south facing slope across from the study site, and (ii) if so, to determine the spread of isolated permafrost lenses across the slope combined with geophysical soundings. On the permafrost site, 88 dominant larch trees (av. age: 210 years) were cored in 5 horizontal transects and the position of each sampled tree was documented in a detailed map of the slope. In addition, 18 trees from the south facing slope were used to establish the reference chronology.

Results show a distinct growth suppression in the reference chronology from 1879 to 1890, where average ring width is reduced by 30% compared to the average of 40 years before and after this time period. This period of reduced growth also occurs in the chronologies of 44 trees (P 1) taken from the permafrost site, which do show growth development comparable to the reference. The remaining 44 trees (P 2) from this site do show a strong growth suppression (up to 80%) starting in the period 1879 to1985 but they do not recover after 1890. Annual growth of 24 trees of P 2 remains reduced until the 1960`s, then annual ring width increases again up to the level which is common for the site. The remaining 20 trees of P 2 show reduced growth until the 1990`s, when a weak growth release started, not reaching the level of common growth.

First comparisons of single trees showing the enduring growth reduction do correspond with locations of permafrost lenses detected by geophysical soundings along a vertical transect across the slope. According to the results of the tree ring analyses it can be assumed that the permafrost lenses at this site developed around 1879, because all trees do show a comparable higher growth level for more than hundred years before this suppression occurred. However, ongoing analysis is directed to answer the question, if these 20 trees do all definitely show the presence of permafrost or just low soil temperatures restricting root growth.

An easy technique to collect wood and bark samples for anatomical studies

A. Boura and D. De Franceschi

Muséum National d'Histoire Naturelle. Département Histoire de la Terre. UMR 5143 Paléobiodiversité et Paléoenvironnement. Case Postale 38 Laboratoire de Paléobotanique. 57, rue Cuvier 75231 PARIS cedex 5.

email : boura@mnhn.fr

Trees, and thus wood, are major components of the biosphere. Wood constitutes a huge source of information regarding several domains like systematic, ecology or adaptative evolution. Despite its significance, wood is not often sampled extensively; most probably due to logistical reasons (harvesting or carrying problems). Moreover the material used for studies is often limited to the collections available at the moment, thus limiting the opportunity to use it, especially in systematic or ecological study.

This works aims to make a review of the different techniques which already exist to collect wood, from the Pressler increment borer, to the new Trephor, draw up a specific methodology to sample wood and finally describe a new cheap and easy method to sample wood, and its handing.

This method only requires the use of a punch, a clearing rod and a hammer. The punch is a tool, initially designed to make holes on quite soft materials such as leather or rubber, but which has proved to be useful to core several trees, from softwood to hardwood, from temperate to tropical species.

This sampling method has several assets. The diameter of the tool, and thus of the core varies from 1 mm to a few cm and can be adjust regarding to the specific use of the wood sample. It is cheap and easy to find. It is light and not bulky. In addition to this, its handing is relatively easy and it allows taking a more or less big sample containing the outermost stem tissues (bark, phloem, cambial zone) and a more or less big part of the most recently formed wood.

The sections prepared from the obtained samples are perfectly usable for anatomy. The samples can be collected as complements for herbarium samples (for systematics) as well as for particular dendroecological studies on tree diameter growth under to climate, soil and forest structure and dynamic influences on individual trees.

The anatomy of invasion:  A dendrochronological investigation of a woody weed, Senna siamea (Lam.) HS Irwin & Barneby, in Australia’s far north

Matthew Brookhouse

The Australian National University, 48 Linneaus Way, 0200 Canberra, Australia

e-mail: matthew.brookhouse@anu.edu.au

Senna siamea, a tree species native to south-east Asia, is currently invading the remote rainforests of Cape York. Its spread towards the riverine forests in the Mungkan-Kandju National Park is of particular concern. Due to its speed, scale and patchiness the invasion has proven difficult to document. Thus, little is known about the process of invasion by this woody species. Dendrochronology has the capacity to provide data on tree age and radial growth rates that can significantly improve understanding of the dynamics of plant invasions. However, the potential of S. siamea for dendrochronology is untested. Thus, the question of whether the species forms annual tree rings remains unanswered. Highly seasonal rainfall in Cape York suggests that it is possible the species forms annual rings. Given the limits of our knowledge of S. siamea and its potential for dendrochronology in Cape York, we propose a two-stage study of the species. The first stage will involve analysis of intra-annual variation in radial growth and wood anatomy. The second component involves the spatial and dendrochronological analysis of tree age and growth data from tree ring samples.

Last millennium multi-proxy record from a raised bog in northern Poland

Anna Cedro¹, Mariusz Lamentowicz², Łukasz Lamentowicz², Grażyna Miotk-Szpiganowicz², Edward Mitchell³, Jacek Pawlyta⁴

¹University of Szczecin, Poland

²Adam Mickiewicz University in Poznań, Poland

³WSL, Swiss Federal Institute for Forest, Snow and Landscape Research, Lausanne, Switzerland

⁴ Silesian University of Technology, Poland

e-mail: Anna.Cedro@univ.szczecin.pl

Stążki peatland is in the initial phase of the palaeoenvironmental studies. Reconstructions are based on analyses of: dendrochronology, testate amoebae, palynological, plant macrofossils and stable isotopes. Aims of the research were: reconstruction of the last millennium environmental changes, reconstruction of local and regional climatic changes, and an attempt to recognize between signal of human impact and climatic change

Monolith sampled from the central part of the mire was dated with two methods C-14 and Pb-210. The sampling of 22 trees was carried out with Pressler increment borers. High resolution approach applied to the peat material and dendro samples allows to obtain precise palaeoenvironmental reconstruction from northern Poland. We hypothesize that proxies used in the study will give us the opportunity to recognize the climatic and human signal in the peat and trees archive.

Also tree rings from the Scots pines growing on the surface were studies to describe the magnitude of human impact during the last 100 years. The chronology (ST) based on 13 individual patterns, cover the period of 143 years (1862-2004), it was used to dendroclimatological research: signature years and response function analysis. No distinct relationships between the ring widths and the climatic conditions were observed. The determining factor of cambial activity of Scots pine growing on bog was human impact and connecting with it changes of ground-water level.

Collars, shepherds and dendrochronology. Traditional activities end at Parc Nacional d’Aigüestortes i Estany de Sant Maurici (Vall de Boí, Alta Ribagorça, Spain)

Mireia Celma Martínez

Prehistory Department-Archaeobotany Laboratory, Universitat Autònoma de Barcelona, Edifici B  Campus de la UAB,  P.C.: 08913 Bellaterra (Cerdanyola del Vallés, Spain)

e-mail : mireia_celma@hotmail.com

National Park of Aigüestortes and Estany de Sant Maurici, in the Catalan Pyrenees, was a territory interpreted exclusively as a natural landscape before 2004. Three years ago, archaeologists from Universitat Autònoma de Barcelona started a new social study focused in the explanation of interaction between societies and natural high-lands.

During prospection field work it was detected a repeated injury in P.uncinata population, long cuts in bark made by human and related with pastoral activities. This raw material was used for production of collars for flocks-herds by shepherds of nineteenth and twentieth centuries. Resulting objects of this local production were studied and related to injuries detected in some areas of National Park. The object is to record last practices of shepherds from high-lands, a lost knowledge that is just still alive in trees. An extensive dendrochronological study of these bark injuries could show a large chronology for understanding the beginning and end of traditional practices in the Catalan Pyrenees.

Thanks to National Park of Aigüestortes and Estany de Sant Maurici (Alta Ribagorça, Catalonia, Spain), Ecomuseu de les Valls d’Àneu (Esterri d’Àneu, Catalonia, Spain), Ecology Department of Universitat de Barcelona (Catalonia, Spain) and Prehistory Department of Universitat Autònoma de Barcelona (Catalonia, Spain).

A junipers woodland story: spatial and temporal patterns in a mixed stand of Juniperus thurifera, Quercus ilex and Pinus sylvestris

Lucía de Soto¹, José Miguel Olano¹, Vicente Rozas²

¹ Departamento de Ciencias Agroforestales, E.U.I. Agrarias de Soria, Universidad de Valladolid, c/ Los Pajaritos s/n, 42003 Soria, Spain.

e-mail: luciadesoto@gmail.com; jmolano@agro.uva.es

² Departamento de Ecología, CIFA de Lourizán, Apdo. 127, 36080 Pontevedra, Spain. e-mail: vrozas.cifal@siam-cma.org

Introduction:

Thuriferous juniper woodlands (Juniperus thurifera L.) develop on continental Mediterranean environment over a narrow distribution and are included as a priority habitat in UE Habitat Directive (Directive 92/43/EEC). They are usually open forest systems or coppice forests historically subjected to intense human management. Thuriferous juniper is the dominant species, but usually coexists with other trees, particularly oaks and pines. Recent structure could be explained either as a result environmental growth constrains for the other tree species or as a consequence of traditional management.

Our questions are: (1) if stressful growing conditions favour juniper dominance, which are the growth pattern of the different tree species in a juniper woodland?, (2) if the structure is influenced by management, which factors determine their past and current structure?, and (3) analysing the results of both hypothesis, what can we infer about the future dynamics in this woodland?

Methods:

The selected stand was located in Cabrejas del Pinar, north-central Spain, at 1300 m above sea level, on poorly developed soils under limiting climatic conditions. All the individuals found in a square plot of 1.44 ha were labelled, mapped, cored and measured. Individuals were divided into two cathegories: trees (DBH > 5 cm) and saplings (DBH < 5 cm). Standard dendrochronological techniques of tree-ring dating and ring-width measuring were performed to compare tree growth and to detect releases. Ripley’s K statistic was used to analyse spatial distributions. Historical information on cattle numbers was used to reconstruct management changes in the past.

Results:

In the middle of XIX century most of J. thurifera trees in the study plot have been recruited and showed low radial growth rates and an abrupt growth suppression in 1880, moreover other recruitment pulse took place in the last five decades. Scots pines (P. sylvestris L.) and holm oaks (Quercus ilex L.) showed higher growth rates and established more recently, since 70’s.

J. thurifera trees tend to be located together in clumps including both genders, but separated from clumps of conspecific saplings. Q. ilex saplings and trees tend to be associated to J. thurifera, while P. sylvestris showed a random spatial pattern.

Discussions:

The low growth rates of J. thurifera in comparison to those of P. sylvestris and Q. ilex may reject the hypothesis to a differential effect of environmental stress. Results suggest that pines and holm oaks perform well in this stand. Cattle density controls junipers, pines and holm oaks radial growth and recruitment. Traditional management abandonment has allowed other species entrance into the juniper woodlands, with juniper facilitation as a nurse plant. If grazing pressure is maintained in higher level than present one, juniper woodlands will preserve theirs actual structure and composition. However, if grazing keeps on low levels, holm oaks and pines will increase the dominance in the stand and relegate junipers to a supporting role.

Inter species comparison of tree ring d¹³C and d¹⁸O from subalpine sites in High Asia

J. Grießinger^1,2, A. Bräuning¹ & G.H. Schleser²

¹ Friedrich-Alexander-Universität Erlangen-Nürnberg, Institut für Geographie, Kochstrasse 4/4, D-91058 Erlangen, Germany

² Forschungszentrum Jülich GmbH, Institut für Chemie und Dynamik der Geosphäre, ICG-V Sedimentäre Systeme, Leo-Brandt Strasse, D-52425 Jülich, Germany

e-mail: jgriess@geographie.uni-erlangen.de

In this study, we present the relationship between climatic factors and annual isotope values (d¹³C; d¹⁸O) in cellulose from tree rings of spruce (Picea balfouriana) and juniper trees (Juniperus tibetica). The subalpine investigation site is situated in the south western part of the Tibetan Plateau, where the annual climate is mainly influenced by a clear shift between summer and winter. During summer, the influence of the Indian and East Asian monsoonal systems becomes predominant, resulting in high summer temperatures and high precipitation amounts caused by strong convective systems. During winter months, the climate of the investigation area is controlled by prevailing westerly winds, bringing cold and dry air masses to the southwest of the Tibetan Plateau. As the high-elevation site is characterized by steep slopes and soils with limited water storage, access to groundwater is almost excluded. Therefore, our site selection emphasizes two important influencing factors for the stable carbon and oxygen isotope fixation in tree rings. Water uptake by the roots should clearly record the d¹⁸O-signal of precipitation, modified by the isotopic enrichment effect of leaf water. The d¹³C-values in tree rings should tape atmospheric conditions during carbon fixation controlled by evapotranspiration conditions at leaf level.

First results indicate for both tree species highly significant negative correlations with precipitation amounts during the summer months. Results of the oxygen ratios of tree rings underline therefore their strong potential to reconstruct past climate variabilities. In contrast, characteristic differences occur within the carbon isotope variations, where juniper trees show only weak signal strength.

The relation between the microscopic structure and the wood density of Fagus sylvatica L. 

Vladimír Gryc, Hanuš Vavrčík, Michal Rybníček, Eva Přemyslovská

Mendel Universtiy of Agriculture and Forestry Brno, Faculty of Forestry and Wood Technology, Department of Wood Science, Zemědělská 3, 613 00 Brno, Czech Republic.

e-mail: gryc@mendelu.cz

The European beech (Fagus sylvatica L.) is one of the most important commercially used hard wood species both in the Czech Republic and other countries in Central Europe. In 2005, its proportion amounted to 6.6 % of the total area of the Bohemian and Moravian forests. The aim of this study was to compare the structure of the juvenile and mature beech wood in relation to the wood density (moisture content 12 %). The comparative analysis between the juvenile and mature wood examined the diameter of vessels, the width and height of pith rays, and the number of vessels and pith rays per 1 mm². The results show that the average vessel diameter, as well as the width and height of the pith rays reach statistically lower values in the juvenile wood than in the mature wood. On the other hand, no significant difference between the two woods has been found in terms of the frequency of vessels per 1 mm². Having said that, the difference in the frequency of rays per 1mm² between the juvenile and mature wood is far from negligible; the juvenile wood has three times as many pith rays as the mature wood. The density of the juvenile wood is higher (r₁₂ = 726,07 kg/m³) than the density of the mature wood (r₁₂ = 701,50 kg/m³).

The project was financially supported by the research invention of Forest Faculty of the Mendel University in Brno, MSM 6215648902.

A predictive GIS model to locate tree-rings in the Los Tuxtlas forests (Veracruz, Mexico)

Genaro Gutiérrez-Garcia,  Martin Ricker

Estación de Biología Tropical “Los Tuxtlas”, Universidad Nacional Autónoma de México (UNAM), Apartado Postal 94, San Andrés Tuxtla, Veracruz 95701, México.

e-mail: genaro.gutierrez@gmail.com

Tree-ring research has been mainly focused on tree species of temperate and semiarid zones. In contrast, relatively few tree-ring chronologies have been determined in the tropics. Recent dendrochronological work reports the presence of annual rings in several tropical areas with short drought periods or long-lasting inundations.  Due to its high tree species diversity and elevational range of 0-1,700 m above sea level the 1,500 km2 Los Tuxtlas Biosphere Reserve is a suitable area to search for previously unreported tree species with dendrochronological potential, from lowland rainforest to pine and cloud forest.  The main object of the present study was to develop a predictive model based on a Geographic Information System (GIS) to identify areas where trees can be expected to form annual rings.  The layers used in the model were climate, insolation, soil type, soil texture, slope, slope position, aspect, and vegetation (all nine in digital raster format). We used the GIS to identify areas with short drought periods, steep slopes, and nutrient deficient soils, and low insolation sites. The predictive model indicates that18.12% of the area can be expected to present annual rings. The corresponding field work for verification will follow next.

Hydrogen Isotopes in a 400-Year Pinus uncinata Chronology from NE Spain

Sarah Hangartner, Marc Filot, Markus Leuenberger

University of Bern, Climate and Environmental Physics, Sidlerstrasse 6, 3012 Bern, Switzerland

e-mail: shangart@climate.unibe.ch

We measured annual hydrogen isotope ratios in α-cellulose of mountain pine (Pinus uncinata) growing in a subalpine forest in eastern Pre-Pyrenees (Massís del Pedraforca). The online equilibration method described in [1] was applied to measure the D/H ratio of the non--exchangeable hydrogen. We compared the δD chronology to the 400-year Pedraforca δ¹⁸O chronology [2]. Although both hydrogen and oxygen originate from source water and share a common pathway until the evaporative enrichment in the leaves, the correlation between the chronologies is poor. Sporadic years show extreme signals in both hydrogen and oxygen datasets. The variability of the hydrogen serie tends to increase since 1950.

References:

[1] M. Filot et al. Rapid online equilibration method to determine the D/H ratios of non-exchangeable hydrogen in cellulose. Rapid Commun. Mass Spectrom. 2006, 20, 3337-3344.

[2] M. Filot. Isotopes in tree-rings: Development and application of a rapid preparative online equilibration method for the determination of D/H ration of nonexchangeable hydrogen in tree-ring cellulose. PhD thesis, University of Bern, Switzerland, December 21, 2006, 104 pp.

Growth rings in selected tropical Meliaceae species

Ingo Heinrich¹ & Hans Beeckman²

¹ Research Center Jülich, ICG-V, Wilhelm-Johnen-Straße, 52425 Jülich, Germany, i.heinrich@fz-juelich.de

² Royal Museum for Central Africa, Leuvense Steenweg 13, 3080 Tervuren, Belgium

Tree-ring proxy data from the tropics are valuable but sought after sources for climate reconstructions and modelling to better prepare for the catastrophic impacts of droughts and floodings caused by long-term climate fluctuations such as ENSO. Although tree rings in tropical trees are often difficult to identify, the tropics still offer a vast pool of potentially valuable tree species for future dendrochronological investigations. However, the challenge remains to find the most useful species. A very efficient approach is to analyse xylarium samples in order to shortlist a number of potentially useful species for dendrochronology instead of conducting arduous and expensive field work in remote places often without any warranty of success.

The current study concentrated on the Meliaceae as it is among the most promising tropical plant families for tree-ring studies. Most of its species are deciduous to semi-deciduous trees and shrubs and often display distinct ring boundaries. Several genera of the Meliaceae (Cedrela, Swietenia and Toona) have already been used successfully in tree-ring research, however, little is known about the remaining 500 species, some of them likely with good potential for new dendro-studies in the tropics.

Hence, wood anatomical analyses were conducted on selected Meliaceae samples filed at the Tervuren xylarium. The analyses concentrated on wood structures visible in cross-sections, that is, the presence of parenchyma bands, distinct changes in vessel and/or fibre sizes, ring widths, incidents and forms of possible false or missing ring structures and any other obvious structural anomalies. Additional attributes collected in Tervuren were origins of the sample, geographical and ecological site descriptions and size/age of the trees sampled. The poster presents first results forming the basis for further tropical tree-ring research.

Tree-ring study of the island formation and riparian forest along a gravel-bed river in the Polish Carpathians

Ryszard J. Kaczka¹, Bartłomiej Wyżga², Joanna Zawiejska³

¹Faculty of Earth Sciences, University of Silesia, Sosnowiec, Poland

²Institute of Nature Conservation, Polish Academy of Sciences, Kraków, Poland

³Institute of Geography, Pedagogical University, Kraków, Poland

e-mail: kaczka@wnoz.us.edu.pl

The Białka River draining the Northern Carpathians, southern Poland, is one of the last relatively undisturbed, gravel-bed rivers in Central Europe. Its riparian zone and the floodplain are subject to human activities, mainly wood harvesting and farming. However, the character of both the island vegetation and the river channel remain typical of the formerly widespread, semi-natural, braided rivers in the Carpathians. The study aims at reconstructing spatial and temporal dynamics of the island development in such a gravel-bed river.

The research was conducted in a 5 km long section of the lowest river course, where the active channel is widest and islands and bars are most common. Twenty-six established islands, their entire population in the section, and the associated pioneer islands were analysed. Standard dendrochronological techniques were employed to determine age structure of trees growing on the islands and in the riparian forest. The age of the oldest specimens was considered to represent a minimal age of the island, and age structure of the vegetation as a proxy of its spatial development. The tree-ring dates were verified by more general information gathered from an analysis of maps and aerial photos. Willow and alder predominate on most of the islands, whereas spruce and pine grow on older islands and in the riparian forest.

So-defined minimal age of islands is related to the occurrence of major floods that effectively change the pattern of a braided channel.  On the Białka River, the last such floods occurred in 1997 and 2001. Although a signal of previous floods is less apparent in tree-ring dating, a comparison of the age of the islands and the riparian forest reveals significant differences in the factors controlling development of both elements of the riverine landscape. When the first is related to the occurrence of floods, the second is more independent of a natural dynamics and largely determined by human activity.

Though preliminary results indicate different scenarios of the island initiation and development, which are registered in the tree-ring proxy, a common pattern exists – the oldest trees grow in the central, best protected part of the islands. The decrease in tree age from the island centre is more pronounced in the upstream than in the downstream direction. Centrally growing trees play an important role in the island development as they trap wood and mineral sediment on the upstream island margin, hence stimulating growth of islands in the upstream direction. That pattern of island formation seems typical of mountain European rivers, from which large wood pieces are typically removed and where the resultant lack of key-member fallen trees prevents initiation of bar and island formation in their hydraulic shadow.

Dendrochronological method in use of dating three mansions from South Estonia

Ragnar Kapaun

University of Tartu, Faculty of Biology and Geography, Institute of Geography, Kirde 1a-19, Elva, Estonia

e-mail: rk@ut.ee

Estonia is considered relatively rich for its architectural heritage, which in some parts can be found very genuine. Although we have plenty of well preserved and restored old buildings, many of them are still in bad condition. With every forgotten place we loose a piece of our history. To prevent that from happening, we have to take care of dilapidated heritage. The least to be done is to explore deeply and preserve all the reasonable material. And this is where dendrochronology has to take part in this extremely important process.

This thesis reflects author’s progress in the field of dendrochronology, with the main aim to date three old buildings using dendrochronological methods. All the buildings are situated in southern part of Estonia: Rootsi dairy farm and Suure-Kambja mansion are in Tartu County and Toolamaa manor in the Põlva County.

The results were definitely interesting. Toolamaa mansion was expected to date to the end of 17th or the beginning of 18th century. Dendrochronological analysis showed that the wooden part of the house was probably built in 1836 or 1837. So, about one century later than guessed. The mansion of Suure-Kambja showed also significant outcome. As the assumed building time was in the end of 18th or the beginning of 19th century, dendrochronological dating indicates to the exact year 1728, awhile after the Great Northern War. The building time of the mansion was budged back in time about half a century. The Rootsi dairy farm resulted with two different dates from different parts of the house. It can be interpreted so that the roof of the building was built in 1835 and evidently in the same year the ceiling beams had been also put into the stone-walled building. Shortly after 1897, in the very end of 19th century some renewing works were carried out, in which some of the timber was replaced.

As mentioned, it is important to continue practicing dendrochronological researches in Estonia. As this work confirmed the area of Estonia can be considered dendrochronologically homogeneous, the work will continue. It is necessary to extend the local tree-ring network and optimize tree-ring chronologies along with taking part in the process of preserving the national cultural heritage. These are the present main goals of dendrochronology in Estonia. 

Dune movements and tree rings: Czolpinska dune, Slowinski National Park, Poland

Marcin Koprowski¹; V. Winchester² ; A. Zielski ³;

¹Laboratory of Dendrochronology. Institute of Ecology and Environment Protection, Nicolaus Copernicus University, Gagarina 9, 87-100 Torun, Poland. koper@biol.uni.torun.pl

²Oxford University Centre for the Environment, School of Geography, Oxford OX1 3QY, U.K.

³Faculty of Geology, Geophysics and Environmental Protection, University of Science and Technology, al. Mickiewicza 30, 30-059 Kraków, Poland.

One implication of climate warming is that dunes in many parts of the world will start to grow and studies are needed to investigate whether trees, affected by encroaching sand, may be used as indicators of dune dynamics. Our study on the famous, mobile Czolpinska dunes in the Slowinski National park, Poland (54°43'30.32"N 17°15'36.79"E) had two main aims: to establish how tree rings of Scots Pine (Pinus sylvestris L.) are affected by dune movements and to estimate rates of movement. The forest at the base of our site, locally named ‘the VIP Dune’ supplied a reference chronology showing tree growth unaffected by sand for comparison with semi-buried trees on a transect up the dune slope.

We analyzed tree-ring widths from the semi-buried stems using classical ring-width measurement, statistics and skeleton plotting techniques to provide (i) dates for initiation of tree suppression and (ii) dates for reaction wood and eccentricity. The horizontal distance from a buried tree to the dune base divided by the number of years since the tree was first suppressed, or began to form eccentric rings or compression wood, supplies a maximum estimate for the rate of sand advance. The estimate is a maximum because, as we found, tree reactions to invading sand may frequently be delayed, with the length of delay possibly dependent on whether dune movement is fast or slow; in which case a tree may have time to adapt and, initially at least, show no visible reaction at all. However, other factors including genetic susceptibility and disease may also control growth reactions, thus reducing the accuracy of annual estimates. Despite these caveats, our preliminary findings are that Czolpinska dune movements have decreased from previously measured rates of between 3.5 m and 10 m/yr, to a maximum between 2 and 3 m/yr since 2000. We hope to return in the following years to check our results by re-measuring sand height on a number of marked trees growing where the dune base met the forest floor in July 2006.

Influence of climate on formation of radial growth Pinus Sylvestris L. in forest and forest-steppe zones of Ukraine

Koval I.M.

Research Institute of Forestry and Forest Melioration, Pushkinska 86, 61024 Kharkiv, Ukraine

e-mail: koval@uriffm.org.ua

Response of pine to climatic fluctuation in different native zones of Ukraine presents significant interest.

Objects of our research were pine pure stands of medium ago located in different zones of Ukraine with slight anthropogenic influence.

We have revealed common pointer years of radial growth in forest and forest-steppe zones for 1946-2001. Years of minimal of growth are 1952, 1956, 1963, 1976, 1979 that characterize small precipitation during vegetation and severe winters. During years of maximum of growth: 1965, 1970, 1978, 1985, 1993 and 1997 was recorded high precipitation during vegetation period.

We have detected that in Polissja radial growth limits temperature of could period (from previous December to current March) in contrast to steppe where influence droughts in period of vegetation on radial increment was observed. Common influence minimal precipitation and winter low temperature strengthen depression of growth. In last twenty years in investigated stands we didn’t reveal decrease of radial growth.

Soil also influences on response of forests to fluctuation of climate. Positive mean correlation between tree ring indexes and hydrothermic coefficients О₃, that represents ratio of warmth and humidity during current year and three previous years and with О₁, that characterizes ratio of warmth and humidity for current year. In this case different reaction of trees growing on soil with different moisture was discovered.

Comparison of densitometrical and histological methods to the identification of early- and latewood boundary in tree-rings of spruce (Picea abies [ L.] Karst.)

J. König, B. Günther, C.T. Bues, S. Marschallek

Technische Universität Dresden, Institute for Forest Utilization and Forest Technology, Chair for Forest Utilization, Pienner Straße 19, D-01737 Tharandt, Germany

e-mail: koenig@forst-tu.dresden.de

The detailed demarcation of early wood against late wood takes place in general using the histological method for conifer woods after MORK. Therefore, microsections were made and the coloured wood cells regarding the cell wall thickness and cell lumen width were measured. To implement multivariate cross correlation (KOENIG et al. 2004) a reproducible early and late wood demarcation is necessary.

The base for the densitometrical method of classification is the ratio between the intra-annual minimum and maximum wood density values. 297 different tree ring sequences with approx. 39.000 wood cells of spruce (Picea abies [L.] Karst.) from upper elevations sites of the Erzgebirge Mountains (Oberwiesenthal, Abt. 368 a1, 1070 m a.s.l., Saxony,) were subjected to densitometric and histological analysis.

It was shown that with the x-ray densitometric method all wood cells were classifiable in early and late wood zones. On the other hand, sometimes the late wood cells of thin and bright tree rings could not be classified after MORK to late wood zones because of the thin-walled wood cells. The late wood zones calculated with both methods were compared with one another for significant differences. As a result, the more practicable densitometrical research method does not differ significantly from the histological method after MORK.

Dendrochronological dating of churches from southern Poland

Marek Krąpiec, Elżbieta Szychowska-Krąpiec, Andrzej Zielski

AGH – University of Science and Technology; Department of Geology, Geophysics and Environmental Protection

e-mail: mkrapiec@geol.agh.edu.pl

In Poland, in many cases problems arise at precise dating of old churches, because written sources often do not specify the time of their building, repairs, or reconstruction. The analyses presented were aimed at determination of the absolute age of timbers from the roof structures of historic churches from the Świętokrzyskie voivodeship in S Poland. The research was carried out in 11 churches, from which altogether over 200 wood samples, mainly of coniferous tree species, were taken. Scots pine (Pinus sylvestris L.) was predominating and wood of fir (Abies alba M.) was occasionally encountered. The dating was made on the basis of regional standards for Scots pine, constructed by A. Zielski (1106-1991) and E. Szychowska-Krąpiec (1622-1996), and for fir – by E. Szychowska-Krąpiec (1106-1997).

The oldest examined object turned out to be the church in Wiślica, funded by the king of Poland Kasimir the Great in the 3rd quarter of the 14th c. Dendrochronologically analysed elements of the roof structure came from fir trees cut down in 1365AD.

The other analysed churches are younger objects; two of them, in Zborówek (1443 AD) and in Czerwony Chotel (1449 AD), represent the middle of the 15th c. In both cases the roof structures of the churches retained wood from that time. The church in Chroberz turned out to be of similar age; dendrochronological dating of wood from the structure indicates 1437 AD, although the source data point out the construction of the church in 1550 AD.

In the cases of younger objects, dated to 16th, 17th, and 18th c., certain differences between the data from archival sources and the dendrochronological dating of wood from the roof structures also appeared. According to the source data, the church in Nowy Korczyn dates back to the middle of the 17th c., however, the analysis did not reveal such old wood. The wood sampled from the structure represents trees cut down in 1776 AD, which may point out repairing of the roof. Similar is the case of the church in Dobrowoda, built in the mid-16th c., though wooden elements of the roof structure were dendrochronologically dated only to the first half of the 18th c. (1734 AD). Lower divergence issued at dating of the church in Małogoszcz, according to the archive materials built in the 1590s, whereas dated wooden elements came from pine trees cut down in 1660 AD.

In the cases of the four remaining churches, out of 11 ones examined, i.e. the 16th and 17th c. churches from Krzcięcice, Imielno, Szaniec, and Kossowo, the results of the dendrochronological dating were in agreement with the archive materials.

The research performed resulted in construction of a local pine chronology, containing 520 rings and covering the period 1257-1776. It also permitted to verify, precise, and specify data concerning history of construction of some sacral objects in the Świętokrzyskie voivodeship.

The influence of oil-shale underground mining on the growth of trees in Kohtla mining area in northeastern Estonia

Kristel Kund, Vivian Uibo

University of Tartu, Institute of Geography, Estonia

e-mail: Krkund@ut.ee

Oil-shale in northeastern Estonia is mined in Ida-Virumaa area on the territory that extends from Kiviõli in the west to Narva River in the east and from Jõhvi in the north to Väike-Pungerja in the south. Oil-shale mining causes numerous negative changes in the environment: hollow gaps beneath the ground may collapse, the groundwater level changes, waste water from the mines is being pumped into the rivers, the micro-relief of the ground changes.  Although the main mining method used in underground mines was chamber mining, in some areas longwall mining by combine transporters was applied. As the face advances the cavity behind the line of hydraulic supports (called goaf) is allowed to collapse. This collapsing reflects on the land surface, causing lowering of it by 0.5 – 1.3 m.

As the ground sinks, the forest growing on it sinks as well. Presumptively the changes in the surface relief affect the radial growth of the trees growing on it.

Tree-ring data has been collected in three different subsided plots of Kohtla oil-shale longwall mining, where mining has been conducted in different years. These data has been compared with tree growth at two control plots with similar environmental conditions.  One research plot consists of three circles, with the radius of ten meters. Within the circles increment cores were gathered from all the trees. The main tree species in the sample plots were Norway spruce and Silver birch. Samples were gathered from 583 trees.

The aim of this research was to find out how the radial growth (tree-ring widths) of trees has changed since mining. One way to detect the assumed influence of the mining is to compare the growth of the trees in mining areas with that of the trees from the control areas. Another option is to compare the radial growth of trees before and after mining in the same tree samples.

Earlier studies on one particular research plot have shown that after surface subsiding the radial growth of spruces has mainly increased and the growth of pines has decreased. The radial growth of trees is also influenced by the age of the tree, position in the relief, tree condition class, weather, inclination of trees, site conditions and many other factors. To obtain more objective results about the influence of surface deformation to tree growth, our further studies contain different research plots and control plots.

Contribution to chronology of conifers in northern and eastern Carpathians (Slovakia and Transcarpathian Ukraine)

Kyncl T., Kyncl, J., Fedaka P., Lukáč L.

DendroLab Brno, Eliášova 37, 616 00 Brno, Czech Republic

e-mail: kyncl@dendrochronologie.cz

The aim of the presented research is the construction of master chronologies of conifer species for northern Carpathian Mts. (Slovakia and Eastern Ukraine). According to our preliminar survey, most of historical wooden constructions in this region are made of fir, spruce and larch. Now the fir chronologies have been compiled; and we have started with the construction of larch chronology.

Fir chronology

On the basis of the correlations among chronologies of living trees, we have established two regions with specific chronologies. Chronologies from western and central Slovakia (west of Prešov) show high teleconnection to chronologies for Moravia (Kyncl J., Kyncl T. 1996) and eastern Austria (Liebert et al. 1998). Chronologies from eastern Slovakia and transcarpathian Ukraine have specific signal and are similar only to chronologies for southern Poland (Szychowska-Krapiec E. 1998).    

The chronology for western Slovakia (ABSLO-we) has now the time span of 1125-1999. The most of the series used in this chronology were taken from historical buildings in Levoča, Banska Štiavnica and Spišské Podhradie.

For the dating of historical wood,  the construction of chronology for eastern part of Carpathian Mts. (ABSLO-ea) is more important than the western one. The samples have been taken from living trees and from historical buildings, especially from wooden churches from Eastern Slovakia and Transcarpathian Ukraine. The chronologies for living trees were constructed for years 1724-2005. The samples were collected from Čergov-Mts, Bukovské-vrchy-Mts (forest Stužica), south foothills of Gorgany-Mts and forest massif Chorna-Gora (total of ca 200 trees). The historical samples have been taken from wooden churches of Archangel Michael from Nová-Sedlica, St. Nicholas in the village Chernogolova and St. Ann in the village Bukivcevo. This material can be crossdated with south-Poland chronology and sumarized to chronology with time span of 1627-1793.

Larch chronology

The larch wood has high frequency especially in constructions from Spiš region. In some specific regions (esp. Levoča), more the 50% of beams are made of larch wood. The closest larch chronologies from Eastern Alps (cca 450 km westwards) are not suitable for cross-dating because of low similarity with our material. In recent period, material from historical objects is been collected and the first floating chronologies are been developed.

References:

Kyncl J., Kyncl T., 1996: Dating of historical fir (Abies alba) wood in Bohemia and Moravia. Dendrochronologie 14: 237-240.

Liebert S., Grabner M., Wimmer R., 1998: A 1000year fir chronology for East-Austria. In.: Proceedings of Europpean dendrochronology workshop „Eurodendro-98“, Kaunas: 18-23.

Szychowska-Krapiec E., 2000: Poznoholocenki standard dendrochronologiczny dla jodly Abies alba z obszaru poludniownej Polski. Kwartalnik AGH, Geologie 26(2): 173-299. 

Subfossil pine woodland and trackways in Campemoor (NW Germany)

Hanns Hubert Leuschner¹, A. Bauerochse², B. Leuschner³ & U. Sass-Klaassen⁴

¹Dep. Palynology and Climate Dynamics, Univ. Goettingen, Germany. hleusch@gwdg.de

²Lower Saxony State Service for Cultural Heritage,Hannover, Germany. bauerochse@nld.niedersachsen.de

³DELAG, Goettingen, Germany. delag_dendro@yahoo.de

⁴Centre for Ecosystem Studies, Wageningen University, The Netherlands. ute.sass-klaassenf@wur.nl.

Most of the raised bogs in Germany are situated in the Lower Saxony part of the North German Lowlands, in a landscape that was moulded during the ice age. In many of these peatlands within the peat, at the base of the raised bog peat, a subfossil wood layer of pine (Pinus sylvestris) exists. At the Campemoor (located in the Duemmer Geestniederung, one of the most important early settlement areas in Northwest-Germany) these layers have been palynologically and dendroecologically investigated. The dendroecological correlation of the frequency, germination and dying-off of these trees with those of the subfossil oak trunks from Lower Saxony shows the change of the ecological conditions in a large time scale. As a result of these investigations the transition from a drier to a more humid climate period that initiated the raised bog growth happened in two phases at the beginning of the 3rd millennium, interrupted by a drier period between 2825 – 2770 BC. Afterwards large areas of former settlement sites within today´s Campemoor became inaccessible and were covered by raised bogs.

The study has to be seen in the frame of the long-term research focus on subfossil bog trees. The Dendrochronological laboratory at Göttingen University holds the worldwide biggest archive of subfossil bog oaks. This dataset comprises c. 3000 samples from NW Germany covering the period from 6000 BC to AD 1000. Synchronous changes in growth pattern and population dynamics of subfossil bog oaks from different locations in NW Europe (Ireland, The Netherlands, Germany) indicate that contemporary „stress-events“ occurred in former wetland woods. The striking common variability in the medium and long frequency domains of the tree-ring records support the assumption that changes in past climate play a key role as a trigger of environmental changes in these wetland woods. The ongoing studies on subfossil pine from NW-German peatlands indicate “stress-events”, most likely linked to striking environmental changes, around 4.700 BC (Jan Eckstein, TRACE 2007) and 2.900 BC which exactly synchronize with those in oaks. The fact that peatlands with pine are known as common stages of mire ecosystems provides the chance to use dendroecological reconstructions of peatlands to get a better understanding of climate influence on bog ecosystems. Moreover, this 7.000-year long monitoring system has the potential to serve as an unique source of information for recent mire restoration projects.

References:

Leuschner,H.H., Sass-Klaassen, U., Jansma, E., Baillie, M.G.L., & Spurk, M. 2002: Subfossil European bog oaks: population dynamics and long-term growth depressions as indicators of changes in the Holocene hydro-regime and climate. The Holocene 12 (6), 695-706.

Bauerochse A, Leuschner B, Leuschner HH (2006) Moorhölzer und Archäologie – umweltgeschichtliche und siedlungsarchäologische Befunde. Berichte zur Denkmalpflege in Niedersachsen 26:40– 45

Leuschner, H.H., Bauerochse, A., Metzler, A. 2007: Environmental change, bog history and human impact around 2900 b.c. in NW Germany – preliminary results from a dendroecological study of a sub-fossil pine woodland at Campemoor, Dummer Basin. Veget Hist Archaeobot (2007) 16:183–195

Light rings in larches: searching the causes

Alar Läänelaid

Institute of Geography, University of Tartu

e-mail: alar.laanelaid@ut.ee

Tree ring series of larches (Larix spp.) growing in Estonia often contain special tree rings which are characterized by three features:

1) Light rings with a very narrow latewood band,

2) The ring width is several times smaller than that of the neighboring rings,

3) They often locate in groups of 2 to 4 alternately with normal rings.

Dendroclimatological analysis of European larches growing in Tartu has shown that there is significant correlation of residual chronology of ring widths with monthly temperatures of  previous April (positive), previous June and July (both negative), previous October (positive), current January, March, and May (all positive). Precipitation sums have significant correlation with larch chronology in previous July and August and in current January (all positive). This correlation can explain the width fluctuations of tree rings, but not the structural peculiarity - extremely narrow latewood. The reason of the light rings can be rather extreme weather events – extreme winter colds, late spring frosts or severe droughts in summer. 

It is also possible that the light rings were caused by any insect damage of two-year cyclicity. The two-year cyclic ring-width pattern of larches with light rings is very similar to that of spruces and firs growing in British Columbia (Zhang & Alfaro 2002). Alas, the specific cycles in tree-ring series of spruces and firs in British Columbia are attributed to spruce budworm Choristoneura biennis, who does not habit larches in northern Europe. The well-known insect pests on larches in Estonia include Coleophora laricella, Pristiphora wesmaeli, P. erichsonii and P. laricis, probably also Coleophora sibiricella, Zeiraphera griseana etc., but none of them is known by biennial life cyclicity. A butterfly Coleophora laricella can eat the foliage of larches in Estonia, while Pristiphora wesmaeli has caused dying the tops of the crowns and even dying the trees in larch cultures in 1958-1960 (Voolma, person. commun.). Today we do not know the actual causes of the cyclic light rings occurring in larch trunks in Estonia. Investigations are continuing to find out the reasons and explain the feature.

Comparison of Scots pine (Pinus sylvestris L.) growth response to climate in dry and calcareous fen sites in Engure Lake are (Latvia)

Iluta Lūce & D.Elferts

University of Latvia, Faculty of Biology, Kronvalda bulv. 4, LV-1586 Rīga, Latvia

e-mail: iluta@lanet.lv

The past history of environmental change as a climatic signal recorded on tree rings is well known for regions in Europe for pines growing in dry conditions, but little knowledge has accrued regarding pine growth on mires, especially on calcareous fens. These areas support mostly low stunted pines, but which can have a surprisingly old age. The aim of the study was to determine the effect of climatic factors on the radial growth of Scots pine Pinus sylvestris L. on a dry soil site in relation to a nearby calcareous fen.

The study was conducted in the Lake Engure Nature Park. It is a unique European wetland (the Ramsar site since 1995) and one of the most important nature protection sites in Latvia. Trees in the dry soil site and calcareous fen in Latvia were sampled by coring (two cores per tree) in the years 2005 and 2006. Tree ring widths were measured using Lignovision, measurement quality was checked with COFECHA and chronologies established using ARSTAN. Correlation analysis was performed to determine the relationship between climatic factors (mean monthly, autumn, winter, spring, summer temperature and precipitation sum) and chronologies. Regression analysis was conducted to determine the proportion of tree-ring width variation explained by the climatic factors. For regression analysis predictors were chosen using response function analysis using the program DendroClim 2002.

Acknowledgment:
This study was partly supported by European Social Fund.

The influence of meandering river activity on the alders form-growth recorded in their tree rings

Ireneusz Malik

University of Silesia, Department of Quaternary Paleogeography and Paleoecology, Sosnowiec 41 – 200, ul. Bedzinska 60, Poland

e-mail: irekgeo@wp.pl

Roots exposure and different growth-forms of riparian black alders have been observed along laterally unstable concave and convex banks and in relatively stable straight reaches of the Mala Panew River, which drains one of the largest seminatural forest complex in southern Poland. The Mala Panew is a meandering river that flows for 20 km through a closed forest. The bottom of the valley is covered by sands of different grain sizes and river migrate laterally about 0,5 m/year. Black alders growing on undercutting banks are mostly leaned and their stems are bended, usually they have exposed root systems. Clumps of alders growing on the concave banks numbered several stems, the stems are 1/3 less in diameter than alders growing near straight or convex banks. The clumps growing on banks forced by erosion are protruding in the middle of the river channel. Alders producing clumps with expended root system because it predispose the plant to obtain stability in opposite to individual stems.  Numerous alders growing on the straight banks reaches have exposed roots system and strongly bended stems to take shape of hook. The stem hooks are formed due long-term sediments erosion around their root systems. As result of this process stem gradually bending under the own weight in conditions of laterally stable channel. The alders growing at a distance of 5-15 meters from convex banks often have similar shapes to trees observed on the straight and concave bank. The similarity is caused by progressive lateral erosion and line of trees withdraw from recent bank.

In general alders growing on river banks produce thinner rings than alders growing in same distance from present river channel  After tilting eccentric growth in alders stems occur, in hook-shape stems at first eccentric growth produce and after several years concentric tree rings are formed. The preliminary investigations suggests that shape of trunks is not only related to fluvial dynamics. Especially it is not clear why in stable reaches trunks of hook shape are more frequent than only slightly bended and why tilted trees are generally rare. The question which arise is to which extent light accessibility control tree curvature, how it is related to channel width and finally what fluvial processes are recorded  in tree rings pattern.

Differential effect of drought on Pinus nigra Arn. radial growth in mesic and xeric sites from southeastern Spain

Darío Martín-Benito¹, Paolo Cherubini², Miren del Río¹, Isabel Cañellas¹.

¹ Departamento Sistemas y Recursos Forestales. CIFOR-INIA. Crta. La Coruña km 7.5 28040 Madrid, Spain

² Swiss Federal Institute for Forest, Snow and Landscape Research WSL, CH-8903 Birmensdorf, Switzerland.

Email: dmartin@inia.es

The response of Pinus nigra Arn. radial growth to drought in the Cazorla Mountain Range (southeastern Spain) was investigated through tree-ring records. Two mesic and two xeric stands were selected on the basis of location, slope, and distance to a water current. For each tree, three ring compartments (total ring, earlywood, and latewood widths) were measured.

In general, there seemed to be no differences between the radial growth of trees from mesic and xeric sites as measured from total tree-ring width. Whereas, there were differences in earlywood and latewood widths. Earlywood widths were greater in xeric sites, where latewood were narrower. Higher abundance of soil water seemed to balance the widths of earlywood and latewood in mesic sites. Mesic site stands showed lower mean sensitivity, lower expressed population signals (EPS), and lower between-tree signals (Rbar).

Climatic signal in the three tree-ring compartments was investigated by means of response function analysis. Radial growth in trees from both types of sites was positively influenced by moist and warm previous-year autumns and cool current-year springs. While current-year autumn temperature positively affected trees in mesic sites, spring precipitation was only significantly correlated with growth of trees from xeric sites. This later fact indicated that in xeric sites water might be a limiting resource for growth, while in mesic sites this limitation might be lower. Thus, the higher relative abundance of wider latewood in tree-rings from mesic sites. This is further supported by the greater negative influence of temperatures of previous-year summers and current-year springs in xeric sites that might decrease the availability of water in the soil through evapotranspiration.

Through a superposed epoch analysis (SEA), the differential growth of tree-rings was assessed during ten drought episodes between 1942 and 1999. All three tree-ring compartments showed reduced growth during these periods, with latewood being the most affected, and earlywood the least. Trees growing in xeric sites experienced greater tree-ring reductions during droughts than those in mesic sites. These differences continued during the year following droughts, when trees in mesic stands almost recovered normal growth. Two years after the droughts, trees achieved a growth greater than that before the drought. This second year after drought, trees in xeric sites grew faster compared to mesic sites.

Trees in mesic sites seemed to experience less stress and recover faster from drought, while trees from xeric sites grew to a higher potential when water in the soil was not limiting.

Radial growth characteristics of Scots pine at seacoast wooded dunes on Kolka Horn

Roberts Matisons & Guntis Brūmelis

University of Latvia, Faculty of Biology, Kronvalda bulv. 4, LV-1586 Rīga, Latvia

e-mail: robism@inbox.lv

Seacoast wooded dunes are protected habitats in the EU (92/43/EEC 2180). These habitats are characterized as highly dynamic structures with rapidly changing environmental factors. There have been few dendroecological studies that have focused on tree radial growth in these habitats.

The aim of our studies was to obtain more information about factors affecting Scots pine radial growth in seacoast wooded dune habitats. We hypothesized that partial burial by sand is a factor affecting stem response above and below the burial margin. We estimated radial growth of sand buried and unburied trees in relation to response to climatic factors. Correlations were determined between buried and unburied tree radial increment, as well as pointer year occurrence and intensity.

The research site was located in Latvia, on the Kolka Horn. Samples were collected from trees, which were washed off a bluff in a storm in January 2005, The burial depth could be estimated by sand debris on the stem. These trees were all located on the beach. Control samples were collected from trees growing up to 200 meters deeper in coasts, where burial was absent.

Two or three tree cores were collected 30 cm above stem base from all trees; additional samples were collected from buried trees at a 1.3 m height above stem base (above burial level). All samples were collected with a Pressler increment corer.

Response to climate was different in buried trees, compared to unburied trees.

Growth/drought responses in tree rings of cultured apple trees

Burkhard Neuwirth¹, Stefanie Johann¹ & Christa Lankes²

¹ Department of Geography, University of Bonn, Bonn, Germany, Meckenheimer Allee 166, D-53115 Bonn

² Department of Horticultural Sciences, University of Bonn, Bonn, Germany

e-mail: b.neuwirth@giub.uni-bonn.de

Tree-ring width is an appropriate parameter for analysing growth responses to climate events especially in areas with extreme climate. In general, tree-ring growth in these areas is influenced by a single climatic forcing factor. Due to the temperate, humid climate in Central Europe, tree-ring growth is forced by changing influences of climatic and non-climatic factors. Analysing pointer years in dendroecological networks recent studies test the suitability of tree-ring widths for climate-growth analyses in low mountain ranges and lowlands. These studies lead to a better understanding of spatially high resoluted tree-ring growth in Central Europe and their climatic forcings.

Taking these aspects into account, we investigate in the recent study the stability of various apple trees (Malus domestica) under changing climate conditions: The study is located in the area of Bonn (West Germany). The analysis is focused on the influences of the record year 2003 on radial growth.

Therefore, six sorts of cultured apple trees (Boskoop, Cox Orange, Elstar, Roter Elstar, Golden Delicious, and Jonagold) from two locations with different site ecological settings were analyzed. In total, 444 radii from stem disks of 111 apple trees were measured using Lintab V. Four radii were averaged for every tree and designed as TMC (tree mean curve). Since trees are only 15 to 19 years old, mean increments of the period 2000 to 2005 were calculated for each TMC and compared sortwise and sitewise. Further, residuals from these years against the mean increment of this time period were used to detect sort related growth responses affected by the drought 2003.

The poster illustrates the results of this dendroecological study and compares them with results from horticultural investigations and crop analyses. Thus, this study documents the suitability of dendroecological studies for investigations on cultured fruit trees.

Calendar-dated Holocene snow avalanche events in the Central Eastern Alps

Kurt Nicolussi¹, Matthias Kaufmann¹, Roland Luzian², Peter Pindur², Andrea Thurner¹, David Zrostvz¹

¹Institute of Geography, University of Innsbruck, Innrain 52, A-6020 Innsbruck, Austria

²BFW, Rennweg 1, A-6020 Innsbruck, Austria

e-mail: Kurt.Nicolussi@uibk.ac.at

The knowledge on Alpine snow avalanche activity in the past is usually limited to the last few centuries. It is mainly based on historical observations and sources. With sub-fossil logs found in a peat bog, the so-called Schwarzensteinmoor, we could establish a record of Holocene snow avalanche events. The peat bog is located in the timberline ecotone of the Zillertal Alps, central Eastern Alps. Dating of the sub-fossil samples is based on the eastern Alpine tree-ring chronology that covers continuously the last approx. 9100 years. Some 180 logs from the Schwarzensteinmoor date between c. 9000 to 700 BP. Many of the samples (n=55) still had a fully developed and usually wide terminal ring indicating a sudden death of the trees caused by snow avalanches. We have found 21 forest destroying avalanche events dated by samples with terminal rings. The oldest event so far happened in winter 6255/54 BC. Furthermore we also analysed the logs and tree-ring series, respectively, from Schwarzensteinmoor to find scars, compression wood and abrupt growth reductions as indicators for forest damaging snow avalanches.

Dating of wooden shelters in Polish High Tatras - tree rings records of the pasturing history in Carpathians

Magdalena Opala, Ryszard J. Kaczka

Faculty of Earth Science, University of Silesia, Poland

e-mail: magdaopala@hotmail.com

The Tatra Mts., known as the highest range of the Carpathians arc, is also one of the main regions of the arc where pasturing on meadows located above timberline, has been developed since 16^th century. This aspect of human activity played a major role in changing the mountain environment of the Carpathians for several centuries. In many locations new openings for pastures were established and the tree-line was driven back as a result. This happened independently to climate dynamics. Recently wooden shelters, the highest located architecture objects in Tatras, appear to be the only remains of former pasturing.

We attempt the systematic dating of shelters, the first project of its kind in the Tatras and within entire the Carpathian Mts. Lately the studies on the highest preserved remote shepherds’ architecture has a special importance. Despite the fact that in 1978 High Tatra’s wooden shelters were accepted as monuments of cultural heritage, the number of them has decreased four times in last century, mainly as a result of the lack of the proper maintenance.

In total, 26 objects from 10 glades (from elevations 1000-1900 m a.s.l.) located in the Polish High Tatras were investigated. Standard techniques for the sampling and dating of historical buildings were used. Approximately 10 samples were extracted from each shelter, thought the number of core samples varied from 3 to 17, due to differing range of timber preservation. Only wood of Norway spruce (Picea abies K.) has been used for construction hence the 400 years long chronology of that conifer was employed to cross-date historical wood. From all 310 historical samples 57% have been successfully dated. The poor number of rings per sample and the condition of wood were the main problem of satisfying cross-dating. Results of dendrochronological dating have shown that preserved shelters are older than that was evaluated by the previous ethnological investigations. The oldest timbers were dated back to XVIII century (maximal age 1756). This is concurrent with the second period of intensive farming in Tatras. Though obtained dates are limited to the period of last 250 years and vary within each building, the general age structure reveals a significant relation to particular stages of expansion and restraint in human activity in the High Tatra. Further analyses of connections with climate dynamics and history can be provided for better understanding of natural and anthropogenic changes of alpine environment in the Carpathians.

Carbon isotopic composition in tree-rings: a temperature record and a tool for biomonitoring CO₂ level

Sławomira Pawełczyk¹, Anna Pazdur¹, Tatjana Boettger², Marika Haupt², Marek Krąpiec³, Elżbieta Krąpiec-Szychowska³

¹Department of Radioisotopes, Institute of Physics, Silesian University of Technology, Krzywoustego 2, 44-100 Gliwice, Poland

²UFZ-Umweltforschungszentrum Leipzig-Halle GmbH, Sektion Hydrogeologie, AG Paläoklimatologie; Theodor-Lieser-Strasse 4, 06120 Halle/Saale, Germany

³Dendrochronological Laboratory, AGH University of Science and Technology, Mickiewicza 30, 30-059 Cracow, Poland

e-mail: Slawomira.Pawelczyk@polsl.pl

Tree rings can be used as archives of climatic and environmental data. For the reconstruction of past climatic and environmental changes there can be used tree rings widths, maximum late wood density and other parameters as stable isotopic composition in tree rings.

Investigations of stable isotopic C, H, and O composition in a-cellulose extracted from tree rings of pines (Pinus sylvestris L.) growing in the ecologically clean Suwałki region, North Eastern part of Poland were undertaken. Presented isotope records cover the period 1900-2003. Those measurements constituted a part of more complex investigations of stable isotopic composition in tree rings for this region for last 400 years in the frame of European project ISONET.

Values of d¹³C, d¹⁸O and d²H observed in the tree ring a-cellulose are compared to meteorological data (temperature, precipitation). On the basis of those investigations  d¹³C, d¹⁸O, d²H can be regarded as an indicator of summer climate change. Relations between isotopic and meteorological data (temperature and precipitation) demonstrate that precipitation influences the stable isotopic carbon, oxygen and hydrogen ratios to a lower extend than temperature. In case of correlation coefficients due to temperature the highest correlation coefficient exists for hydrogen (r=0.57, n=73, p<0.001) from among the three investigated isotopes.

Carbon isotopes are widely used as indicators in the study of atmospheric CO₂ variability in space and time. After removing individual components of d¹³C originating from climatic factors (temperature and precipitation) CO₂ emission was estimated, but only in terms of quality.

Tree ring investigation of alder posts from the foundations of the Vilnius royal palace

Rūtilė Pukienė

Vytautas Magnus University Faculty of Natural Sciences ERC Dendroclimatology and Radiometrics Group

Ž.E.Žilibero 6, Kaunas, LT-46324 Kaunas, Lithuania;

e-mail: r.pukiene@gmf.vdu.lt

The cultural layer of the Vilnius Lower Castle territory has been accumulating at least since the end of the 13^th century. It is rich with remnants of different wooden constructions. For centuries the main tree species used in wooden constructions (houses, pavements, wooden frameworks under masonry constructions, etc.) was pine (Pinus sylvestris L.). But there was a period in the territory development when black alder (Alnus glutinosa Gaertn.) timbers were used in large amounts. Investigation of wooden frameworks from under building basements has revealed that alder timbers were used for some phases of the Royal Palace, the palace premises and the wall north of the palace construction.

Four groups of alder logs from different constructions were dendrochronologicaly analysed. All logs were with bark. Less than 60 years old trees were used for posts and frameworks in C basement in SE wing of the palace and for posts under the wall north of the palace. Together with younger than 50 years old trees, alders of 70-100 years old were used for W basement in NE wing of the Palace and the third premise. The oldest tree had 106 annual rings.

Relative cross-dating of ring width series of alder logs has demonstrated that W basement of the Palace and the third premise were built almost contemporary. The trees for W basement were felled in winter of relative 91/92 year – May of 92 year. The trees for the third premise foundation were felled in the autumn – winter of relative 92 / 93 year. A floating 106 years long alder chronology, relatively dated -13 to 92, was constructed using tree ring series of these two groups.

The alder logs for the foundation of the wall north of the palace were felled two years later than the logs for C basement in SE wing of the Palace. Cross-dated ring width series of these two groups were the basis to build a 54 years long chronology. The chronology shows the best agreement with the former 106 years long chronology in a relative position 8 to 63.

Reconstruction of geomorphic processes using anatomical variations of exposed roots (Fagus sylvatica)

Sahling, I. ¹, Gärtner, H. ² & K.-H. Schmidt¹

¹ Martin-Luther-University Halle-Wittenberg, Institute of Geosciences, Von-Seckendorff-Platz 4, 06120 Halle, Germany; E-mail: ingo.sahling@geo.uni-halle.de ; karl-heinz.schmidt@geo.uni-halle.de

² Swiss Federal Research Institute WSL, Züricherstrasse 111, 8903 Birmensdorf, Switzerland; E-Mail:

holger.gaertner@wsl.ch

The theses presented focuses on the determination and verification of wood anatomical changes in annual growth rings of beech (Fagus sylvatica L.) roots due to exposure. Further, the new findings are applied to date and reconstruct the initial phase of massive block displacements (opening of tension cracks) along the Wellenkalk-cuesta scarp (Wellenkalk-Schichtstufe) in the southern Thuringia Basin, Germany.

For the first time determination of specific anatomical features related to exposure in roots of hardwoods, 21 roots of 10 Fagus sylvatica L. trees and -as a control- 13 roots of 5 Pinus sylvestris L. trees were artificially exposed in two test areas: Area 1 within the vegetation period 2003 and area 2 before the beginning of the vegetation period 2004. 154 samples were taken in December 2004 (area 1) and November 2005 (area 2) for further wood anatomical analysis.

Microscopic analysis confirmed that all roots did show distinct wood anatomical changes related to exposure and these changes occurred simultaneously in beech and pine roots. Amongst other changes described in detail in the results chapter, the persistent size reduction of vessels of more than 35% in roots of beech was determined as the specific anatomical feature indicating the first time of exposure. Moreover, sudden exposure resulting in an immediate vessel size reduction can be differentiated from continuously exposed roots, where vessel sizes decrease continuously over longer time periods.

For the application of these results, 180 discs of 50 roots (33 trees) were sampled and detailed geomorphic mappings were conducted at 19 sites showing tension cracks along the cuesta scarp. In addition, cores were taken from the stems of these trees for complementary dendrogeomorphological analysis and 74 trees were cored to establish three local reference chronologies as a control.

As a result, (i) the initial phases of block displacements at the different sites were determined by dating the year of tension crack opening and (ii) antecedent movements prior to the openings were reconstructed by analyzing growth reactions in the stems of the adjacent trees.

Finally, comparing the reconstructed phases of the geomorphic processes with precipitation data available for the region, showed a definite relation between the opening of tension cracks and extreme precipitation events.

Suess effect in Poland, Central Europe,on the basis of radiocarbon  investigations  in tree rings

Barbara Sensuła, Anna Pazdur

Silesian University of Technology, Institute of Physics, Department of Radioisotopes, GADAM Centre of Excellence, Krzywoustego 2, 44-100 Gliwice, Poland

e-mail: Barbara.Sensula@polsl.pl

This is a summary of the research results on Suess effect in Poland (Central Europe).

The volatility of radiocarbon concentration in tree rings is an useful tool for the analysis of climate and antrophogenic changes over the last 150 years. Dendrological research gives a chance to detect these changes with a high resolution.

 The tree ring samples were collected from an industrial area (Ruda Slaska, Cracow, Chorzow) and the ecologically clean regions  (Augustow and Niepolomice Forest). In this research, we used wholewood and alpha cellulose.  Radiocarbon measurements were performed using the liquid scintilation counter (LSC) in the Gliwice Radiocarbon Laboratory, Poland and accelerator mass spectrometer (AMS) in Nagoya University, Japan.

Since about 1955, nuclear tests have added considerable amounts of 14C to the atmosphere.

Increasing of mining and combustion of fossil fuels like coal, petroleum, natural gas in the industrial area caused emission of carbon dioxide to the atmosphere and changes of carbon isotopic composition in the atmosphere and other carbon reservoirs. First investigation of contemporary tree samples by Suess showed that their radiocarbon activity was lower than in samples from the middle of the 19th century. The Suess effect has a global character that is the consequence of air masses mixing in the atmosphere and it is reflected in annual tree rings.

Reaction of larch trees from eastern taimyr to climatic changes caused by major volcanic eruptions during the last 2 millenniums by tree-ring and isotope data

Olga V. Sidorova, ¹Tatjana Boettger, Eugene A. Vaganov, Mukhtar M. Naurzbaev

V.N. Sukachev Institute of Forest SB RAS, Russia

¹UFZ - Helmholtz Center for Environmental Research, Germany

E-mail: ovsidorova@forest.akadem.ru

We analyzed reaction of larch trees (Larix gmelinii Rupr) growing in the Eastern Taymir [72N-102E] to extreme climatic changes after major volcanic eruptions in the relevant periods based on dendrochronological and isotope (d¹³C, d¹⁸O) data.

The annually isotope data sets for wood cellulose of always four individually analyzed trees for the Eastern Taimyr were obtained at the first time for the special periods A.D. 516-560, 1243-1286 and 1614-1654. The chosen time periods correspond to historically known major (global) volcanic eruptions events. All four analyzed trees for each period have a good agreement and synchronism between each other for both isotopic characteristics (R=0.7; p<0.05). We revealed that the d¹³C and the d¹⁸O of cellulose as well as tree-ring width clear fixed reaction of trees on thermal regime for all investigated periods. However stable isotopes give us supplementary information about moisture regime which fixed in d¹⁸O of cellulose for the periods from AD 516-560 and AD 1614-1654. We established that period from AD 516-560 shows differences with other periods in isotope ratios as for carbon as well as for oxygen up to 0.5 ‰. For all analyzed time periods were revealed high statistical relationships between d¹³C and d¹⁸O of cellulose (up to 0.6-0.7). Comparison analysis between all periods shows highest correlation relationships between June-July air temperature reconstruction and isotopic data (d¹³C, d¹⁸O) for the period from the AD 516-560 (R=0.62; p<0.05 and R=0.42; p<0.05 correspondingly).

Sapwood Estimates of Common Oak (Quercus robur L.) in Estonia

Kristina Sohar and Alar Läänelaid

Institute of Geography, University of Tartu, Estonia

e-mail: kriss8@ut.ee

Common oak (Quercus robur L.) is one of the most investigated woods in dendrochronology in Europe. However, oak is a problematic object to date, as its sapwood is often removed by woodworking and decay in archaeological samples. Oak sapwood rings may also be uncountable because of woodworm damage (Hillam et al. 1987). Number of sapwood rings is necessary for precise dating, as the last sapwood ring indicates the felling date. Thus the number of sapwood rings in living trees is examined to estimate the missing sapwood rings on dating objects. This method has been widely used in Europe. However, so far no such studies have been implemented in Estonia, except K. Sohar (2006).

In this research a total of 75 oak samples from Estonia was examined. The statistical analysis gave 3-22 sapwood rings (if sapwood was distinguished from heartwood by absence of tyloses in earlywood vessels) and 6-21 sapwood rings (if sapwood was distinguished by colour), both within 95% confidence limits. Comparing these results with earlier studies, the general European trend of decreasing sapwood ring number towards the East (Hillam et al. 1987) was confirmed.

There was no good correlation found between the number of sapwood rings and heartwood characteristics studied to estimate missing sapwood. The largest amount of variability of sapwood number is described by average ring width of heartwood - 30%, if sapwood was distinguished by colour; and 17%, if sapwood was distinguished by the absence of tyloses.

The results of this research will help to improve the precision of dating Estonian oak objects. Further researches of sapwood of common oak should be expanded also to Latvia and Lithuania. The investigation is needed to explain the distribution of historical Estonian oak timber in Europe.

References:

Hillam, J., Morgan, R. A., Tyers, I., 1987. Sapwood Estimates and the Dating of Short Ring Sequences. In: R. G. W. Ward (Editor), Applications of tree-ring studies: current research in dendrochronology and related subjects. British Archaeological Reports International Series, Oxford, pp.165-185.

Sohar, K., 2006. Eesti hariliku tamme (Quercus robur L.) maltspuidu varieeruvus ja kasutamise võimalused dendrokronoloogias. BSc Thesis, Institute of Geography, University of Tartu, pp. 40.

Fluorescence microscopy utilization for lignin detection in wooden cell wall in spruce

Hanuš Vavrčík¹, Vladimír Gryc¹, Michal Rybníček¹

¹ Mendel University of Agriculture and Forestry Brno, Faculty of Forestry and Wood Technology, Department of Wood Science, Zemědělská 3, 613 00 Brno, Czech Republic

e-mail: vavrcik@mendelu.cz

A method of lignin detection in cell walls of xylem of differentiating tree-ring in Norway spruce was developed. This method is based on autofluorescence of lignin as determined by reflected fluorescent microscopy. Autofluorescence of lignin was observed at 340–380 nm wavelength of excitation radiation as blue fluorescent light and at 510–560 nm wavelength of excitation radiation as red fluorescent light. There was no emission of the fluorescent light observed at 450–490 nm wavelength. Software for image analysis was used to combine (logical sum) the fluorescent picture with the common light picture.

This method is also useful for observation of microscopic wood structure of non microscopic piece of wood, i.e. making of microscopic slices of wood sample is not required.

The project was financially supported by the research plan of LDF MZLU in Brno, MSM 6215648902.

Linking tree-rings and ecosystem research

Pascale Weber

Swiss Federal Institute for Forest, Snow and Landscape Research, WSL, CH-8903 Birmensdorf, Switzerland

e-mail: pascale.weber@wsl.ch

Tree-rings have been widely used as proxies for reconstructing climate, stand dynamics, forest fires and insect calamities. However, not many studies have dealt with tree-rings as proxies for ecosystem research with regard to patterns and processes of nutrient cycling and interactions between trees and soil. Trees integrate information from their local up to their global environment. Consequently, they also contain information about soil formation and soil biological and physico-chemical properties of the forest ecosystem, which they belong to. However, relationships between soil processes and radial growth in trees have rarely been studied so far. The aim of this contribution is to highlight the potential of linking tree-rings and ecosystem research from a general point of view. More specific, potential research questions in this new field are illustrated by two case studies, one on Scots pine forests in Scotland and the other one on beech forests in Switzerland.

Changing climate sensitivity in northern forests – problem, challenge or not important?

Martin Wilmking, Yongxiang Zhang, Jayendra Singh, Glenn Juday, Rosanne D’Arrigo

Institute for Botany and Landscape Ecology, University Greifswald, Grimmer Strasse 88, 17487 Greifswald, Germany

e-mail: wilmking@uni-greifswald.de

Dendroclimatological research is often based on the assumption that the relationship between tree growth and climate is not variable over time. This assumption, however, has been challenged recently. Here, we explore how climate sensitivity of trees growing in northern forests of Alaska, Canada, Russia and high altitude forest of Asia has changed over time and what effects this might have for climatic reconstruction. In our study, most trees have increased their climate sensitivity in the latter part of the 20^th century, and in several cases former positive relationships with climate variables have become negative or vice versa.

Common drivers of this change in sensitivity include stress related features, threshold effects, or simply methodological issues of analysis.

Dendroclimatology in Scotland: the potential for a 1000-year climate reconstruction

Ewan Woodley

University of Wales Swansea, Singleton Park, SA2 8PP Swansea, United Kingdom

e-mail: 292870@swan.ac.uk

Ring-width, density and stable isotope data from tree rings have been utilised in a number of Scottish climatic reconstructions. However, past land-use practices and the local maritime climate severely limit the preservation of suitable sample material in situ making construction of long (multi-centennial to millennial length) tree-ring chronologies a challenging task.  Pinus sylvestris L. from ancient pinewoods in north-west Scotland may represent an archive of climate sensitive material, yet this approach is reliant on the location and sampling of suitable standing deadwood, submerged wood or building timbers for chronological extension beyond the range of living specimens. This poster presents preliminary results from an initial field campaign to assess the dendroclimatic potential of this region.