Aktuelle Projekte
Can complementarity effects in mixed forests mitigate negative drought impacts on tree growth and survival?
Die Buche hat stark unter den jüngsten außergewöhnlichen Dürreperioden in Mitteleuropa gelitten. Während viele Bäume nach der extremen Dürre 2018 Anzeichen von Kronensterben aufwiesen oder gar gänzlich abstarben, zeigten andere Bäume in der Nachbarschaft kein Kronensterben oder nur geringe Schäden. Die Gründe, warum einige Bäume stärker betroffen waren als andere und welche prädisponierenden Faktoren einzelne Bäume anfälliger machen als andere, sind noch wenig bekannt. Um diese Fragen zu untersuchen, werden im Zuge des Projektes verschiedene auf Jahrringen basierende Analysen (Jahrringbreite, Isotope und Anatomie) angewandt und kombiniert. Darüber hinaus werden verschiedene statistische Methoden eingesetzt, um Signale zu erkennen, die auf eine Schwächung der Buche hindeuten könnten.
European beech has strongly suffered from recent exceptional droughts that hit Central Europe. While many trees showed severe signs of crown dieback or died following the 2018 extreme drought, other co-occurring and neighboring trees showed no sign of dieback or only minor damage. The reasons why some trees were more severely impacted than others and which predisposing factors make some trees more vulnerable than others are still poorly understood. To investigate these questions a variety of tree-ring based analysis (tree-ring width, isotopes and anatomy) are applied and combined. In addtion, various statistical methods are used to try and detect signals that might indicate a weakening of the tree.
Supervision: Dr. Mathieu Lévesque (ETH), Prof. Harald Bugmann (ETH)
Mixture effects on the climate sensitivity of European larch, silver fir and Douglas fir along a bioclimatic gradient in Switzerland
With the rise in temperature and increase in drought frequency in Central Europe, the use of native and non-native drought tolerant tree species has been promoted as an adaptive silvicultural strategy for the sustainable provision of forest ecosystem goods and services. However, little is known about the mixture effects on drought sensitivity and growth of native and non-native tree species. The goal of this project is to determine the mixture effects on climate sensitivity of European larch, silver fir and Douglas-fir across a moisture gradient in Switzerland and to disentangle the influence of site conditions and species composition on species-specific drought sensitivity and growth performance. Tree ring and stable isotopes data will help answering the questions along with the data on the neighbouring trees collected in the field. This project will provide new information on the drought vulnerability and mixing effects of native and non-native species that will be used for the development of adaptive forest management strategies in the face of climate change.
Supervision: Dr. Mathieu Lévesque (ETH), Prof. Harald Bugmann (ETH)