New SNF project funded
The Swiss National Science Foundation funded one of our recent grant applications which will bring two new PhD students to the group. The funded project will focus on the acclimation potential of temperate European tree species to increasing drought. Over four years, we will investigate the carbon and water relations of ten tree species at our experimental SCC II research site in Hölstein.
Project Description:
Global climate change and in particular changes in the hydroclimate towards dryer and warmer summers will impact the structure and composition of central European and other forests on the planet. The extremely hot and dry summers that Europe has experienced in 2003 and in 2018 have already demonstrated the severe impacts that a changing climate will have on tree and forest function and composition for these ecosystems. Critical mechanisms that determine how drought will impact the functioning of trees and forests are, how- ever, poorly understood. This makes it difficult to anticipate the consequences of a future and dryer climate for key ecosystem functions and prevents the development of silvicultural management plants for more re- sistant and resilient forest ecosystems. In particular for temperate European forests important questions re- garding the drought response strategies of different species and their acclimation potential to a new climate are not well understood. Partly this is, because most studies addressing the water relations of trees have - for practical reasons - worked with seedlings and saplings in potting systems and results from these experiment - albeit insightful - are difficult to extrapolate to mature trees and real-world drought conditions.
Here we propose to close this gab and to address the effects of drought on mature trees from ten different temperate European species in a large-scale ecosystem manipulation experiment. The experimental infra- structure has been established since 2018 in a diverse temperate Forest near Basel, Switzerland. The site is now equipped with key infrastructure, including a canopy crane and the pre-treatment phase has now been completed. Large rainout shelters will be installed at the site in winter 2021/22 to manipulate growing season precipitation inputs to the site. With this proposal we seek for funding to use this infrastructure to assess the drought response strategies, the physiological, anatomical and morphological mechanisms that determine these drought response strategies, as well as the acclimation potential of ten tree species. From our work, we expect the following outcome: First, we will provide the first comprehensive empirical characterization of the drought response strategies of key temperate European tree species. Second, we will identify the trait syndromes that govern the different drought response strategies in these species and will identify important tradeoffs between traits and function. Third, we will provide one of the first large scale across-species as- sessments of the acclimation potential of mature temperate European tree species to reduced water availabil- ity and fourth, we will identify the key traits that are responsible for these acclimations.
We will resolve with our experiment important biological questions and expect to reveal mechanisms that contribute to a much improved understanding of plant and in particular tree responses to changes in water availability. Our experiment will have also implications for silvicultural planning and forestry in central Eu- ropean forests, as it will experimentally determine the drought sensitivity and drought vulnerability of some of the economically and ecologically most important tree species of these ecosystems.