Finished Projects

„Analysis of Vitality Problems of Douglas-fir in Rhineland-Palatinate“

In the forest region “Bienwald” in Rhineland-Palatinate a decreasing vitality of Douglas-fir has been observed during recent years. Previous investigations of this phenomenon could not find one simple explanation. A pilot study using tree-ring analysis indicated that during the summer drought 2003 the trees were weakened.
For a better understanding of the causes of the observed vitality losses this project has been initiated.
To achieve this aim a representative analysis of reference trees initiated. New, as well as conventional methods of dendroecology will be applied to examine the impact of weather conditions on tree growth as an indicator for vitality. HF-densitometry will be employed complemented by cell structure analysis. Especially the already found influence of the year 2003 and its impact on the vitality in subsequent years will be analysed. Furthermore possible impacts of genetics will be investigated.

Natural dynamics in subalpine forests

In alpine regions, spruce-dominated subalpine forests fulfil important protoection fuctions against avalanches and other natural hazards. Since many decades there is a high effort to actively maintain these protection forests. Of particular concern are open forest structures near the timberline with a insufficient ability to prevent avalanche releases and uniform, dense forests in the self-thinning stage. In this research project we focus on these two critical forest types in order to answer the following questions: (1) How to develop open subalpine forest structures with an insufficient protective effect against avalanches over time? (2) How fast and on which spatial scale develop dense, uniform forest structures without human intervention? (3) How are these processes influenced by different site conditions?
to address these questions we work with inventory time series as well as with dendroecology. We use data from three periods of the Swiss forest inventory (LFI 1983-85, 1993-95, and 2004-07) to examine the natural dynamics of such subalpine, spruce dominated forests in the self-thinning phase. Therefore we identify unmanaged forest areas related to our research questions and analysethem with GIS and multivariate statistical methods. We complement these analyses by additionally excluding circa 20 plots over the Swiss Alps, where we sample and dendroecologically analyse tree cores in order to reconstruct stand history, age structure, and forest development. The same method will be used in similar plots in the Bulgarian Alps for comparing two different ecosystems with similar conditions and tree species. In addition, we examine the dynamics in open forests close to the timberline. We use data from forest avalanches, sampled from 1985-1990 for comparing the situation in this period with the situation todax by sampling the same plots again.
Our results will provide decision support and will help to set priorities in the management of protection forests on a wider base of knowledge.

Cell structure analysis of tree-rings of beech (Fagus sylvatica) and spruce (Picea abies) from the sites of the soil condition survey in Baden-Württemberg

The co-operation project is part of a larger interdisciplinary research project dedicated to the analysis of climate change impacts on forest ecosystems. The main contribution of the co-operation project is the quantitative analysis of drought stress and drought stress intensities on tree growth. The cell-structure analyses provide the empirical data basis and modeling results for the validation of soil water models on the site/stand and landscape scale. In the Tree-Ring Laboratory of the Institute for Forest Growth the wood samples will be prepared with the high precision flying diamond cutter and analyzed using the existing image analysis software. Radial profiles of tracheid diameters and cell-wall thickness will be measured along three cell rows per tree-ring for the drought years 1976 and 2003 as well as for some years before and after the drought events.

Cell structure analysis of tree-rings of spruce (Picea abies) from the Level II sites (sites of the forest intensive monitoring programme) in Baden-Württemberg

The co-operation project is part of a larger interdisciplinary research project dedicated to the analysis of climate change impacts on forest ecosystems. The main contribution of the co-operation project is the quantitative analysis of drought stress and drought stress intensities on tree growth. The cell-structure analyses provide the empirical data basis and modeling results for the validation of soil water models on the site/stand and landscape scale. In the Tree-Ring Laboratory of the Institute for Forest Growth the wood samples will be prepared with the high precision flying diamond cutter and analyzed using the existing image analysis software. Radial profiles of tracheid diameters and cell-wall thickness will be measured along three cell rows per tree-ring for the drought years 1976 and 2003 as well as for some years before and after the drought events.

 Effects of climate and weather on tree growth

This research project deals with the effects of climate and weather on tree growth and pays special attention to site and stand structure. The investigation is based on more than a 100 years of time series data of height, and radial increment analysis. Also, information on tree ring density profiles, cell structure within tree rings, and fractions of stable cell wall isotopes was used. This data was combined with climate data from climate stations from the network of the German Climate Service. The growth reaction is quantified as a function of various moisture, temperature and radiation conditions. Sites were selected along a climate radiant from the planar elevation of the upper Rhine valley lowlands up to the high mountainous elevation of the southern Black Forest on south-west exposed summer and north-east exposed winter paying special attention to water capacity of the soil substrate. The site related comparison of growth reactions of Norway spruce, fir, European beech and oak is used as a base for the development of multivariate climate growth models. By applying various methods of tree ring analysis, the possibilities of quantitative climate growth analysis for each single method and for a combination of various methods are investigated.
 

CAMBIFORRUS - Identification and management of environmental risks associated with man-made changes using cambial activity monitoring of trees in forests of North-Western Russia

Kick-off Meeting on 20-21 Feb 2007

Environmental effects on the growth of Norway spruce (Picea abies (L.) Karst.) and oak (Quercus spec.) using image analysis methods that quantify cell structure on cross sections

The effect of environmental factors on the diameter growth of Norway spruce, oak and European beech is on the cell level. First the methods for preparing cross sections and the computer-added image analyis for the automatic measurement of cell parameters are developed. In order to quantify climatic effects on the development of cell structure, climate data with high time resolution from various stations of the network of the German Weather Service are used. For quantifying the non-climatic effects, trees from fertilizer experiments, from clonal experiments, as well as trees exposed to specific biotic and abiotic influences are analysed. Besides the high resolution measurements of the radial expansion of tree stems the inter- and intraannual cell structure is analysed in addition to traditional radial growth analysis and the results are compared with one another. On the basis of long-term dendroecological observations, growth-relevant environmental conditions and their extent are quantified and the reaction of the cell parameters to the environmental conditions are explained. The results are used as a basis for the development of growth models.

 

Changes in the growth of Norway spruce (Picea abies (L.) Karst.) due to changing climatic conditions on sites in Central and Northern Europe (SPRUCE GROWTH)

The aim of this EU project, which is coordinated by the Institute for Forest Growth of the University of Freiburg is to analyse the short-term intraannual growth reaction and long-term growth development of Norway spruce in various regions in Northern and Central Europe. On the basis of a large arean, the comparison of tree growth, sensitivity of growth reactions and mortality is analysed as a result of age and stand density paying special attention to climatic influences, growth related environmental effects and effects which possibly cause changes in growth trends. The influences are identified and their effects quantified. Based on this, scenarios for future growth development under changing climatic conditions are developed on a regional level.

 

Analysis of causes of accelerating growth in European forests: Relationships between changes in growth and the nutrient status of Norway spruce, Scots pine and European beech forests in Europe (RECOGNITION)

The aim of the interdisciplinary research project is to analyse possible causes of the growth changes in European forests observed over several decades. The complex interrelationships between nutrition and growth of Norway spruce, Scots pine and European beech forests in Europe are analysed with special respect to spatial and time variability from the growth, soil and nutrition point of view. The database consists of long-term observations taken from intensive forest ecosystem case studies as well as from inventory data of national and supranational environmental network. The empirical data are analysed with multi-variate methods of time series and geostatistics and used for further development, calibration and validiation of process-based forest ecosystem models.

In addition, 19 further parters from various European countries are involved.
 

Compression Wood in Conifers-the Characterisation of its Formation and its Relevance to Timber Quality

The term compression wood is used to describe the wood that tends to form in conifers on the underside of leaning stems, on the leeward side of trees exposed to strong winds, in crooked stems and in the lower part of trees growing on a slope. The structure and chemical composition of compression wood differs from that of normal wood. It can cause major problems in the wood processing industry, resulting in a deterioration in both mechanical properties and dimensional stability. In this project the mechanisms of compression wood formation will be studied along with the impact of site factors and silvicultural practices on its development and subsequent wood quality. The relationship between wood quality parameters and the properties of the end product will be determined, in order to better meet the demands of the end user. This research will help to integrate information about compression wood through the entire wood chain, from the primary forest production to the end user. The output of the project will be advanced decision support tools in the form of predictive models linking silvicultural practice with raw material properties and the end product performance.
Objectives: The overall objective of the project is to obtain a long-term improvement in the quality of softwood timber products in terms of mechanical properties (strength and stiffness) and geometrical stability (warp, distortion) related to the occurrence of compression wood. The general effects of compression wood on the performance of sawn timber are a reduction in the strength, stiffness and dimensional stability, resulting in a decrease in yield of high quality end products and consequent financial losses. Work will be undertaken on Sitka spruce, Norway spruce, Scots pine and European larch. These are commercially important conifer species throughout Europe and will be used to develop methodologies appropriate to other conifer species. The growth patterns of spruce, pine and larch are very different, as a result of which the formation and presentation of compression wood varies among these species. By working on different species, common characteristics in compression wood formation and behaviour can be identified and knowledge obtained that can be readily applied to other conifers.

EU-Projekt Nr. QLK5-2001-00177 Compression Wood in Conifers – the Characterisation of its Formation and its Relevance to Timber Quality (Compression Wood)

 

A French-German Expertise: Assessment of the 2003 Drought and Heat Impacts on Forests ("Drought 2003")

The persistent drought and heat of the summer 2003 caused severe damages in large part of European forests. Challenged by this extreme weather phenomenon French and German forest scientists jointly initiated a multidisciplinary expertise “Drought 2003”: A synthesis about drought effects on forests will be provided and consequences for forest management to prevent negative impacts of future drought will be analyzed by this expertise.

Working groups: http://www.gip-ecofor.org/ecofor/publi/page.php?id=1736

Within the scope of the expertise two public events are organized:

1) French-German Conference “Effets de la sécheresse et de la canicule 2003 sur les forêts en France et en Allemagne / Auswirkungen der Trockenheit und Hitze 2003 auf die Wälder in Frankreich und Deutschland” on 25th March 2004 in the European Parliament, Strasbourg, France: This bilingual conference was directed to national and regional forest decision makers and practical experience.
Details: http://www.gip-ecofor.org/ecofor/publi/page.php?id=2261

2) Scientific Conference “Impacts of the Drought and Heat in 2003 on Forests” from 17th to 19th November 2004 in Freiburg, Germany.
Details: Drought 2003

Contact: Prof. Dr. Dr. h.c. Heinrich Spiecker

The effect of magnesium, nitrogene and water supply on the needle, shoot length and diameter growth of Norway spruce and silver fir on fertilized plots

In the ARINUS research areas Schluchsee and Villingen the effects of an experimental (NH4)2SO4 resp. MgSO4 application on Norway spruce growth dynamics was analysed, paying special attention to nutrient status, climatic conditions and soil water content. Stem and crown development was analysed by measuring tree rings and shoot length for each year. In addition, radial changes of the trunk of spruces was measured continuously. The development of needles and the nutrient content of the needles of each year was quantified. The differences between the growth parameters of the different treatments showed the extent and sequence of growth deviations. These deviations were compared to the dynamics of nutrient cyling which were analysed by other research groups within the frame of a multidisciplinary research project.