The effects of fructification on the diameter growth of forest trees subject to drought stress.

• Applicant: Professor Dr. Thomas Seifert
• Subject Area: Forestry
• Term: since 2021
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 454840041

There is mounting evidence that fructification patterns of our forest trees are changing due to climate conditions. In particular, the coincidence of fructification and drought stress, which has occurred more frequently in the recent past, appears to have a substantial impact on the growth behaviour of our forest trees. However, these effects have not been quantified yet and often monocausal conclusions are drawn from drought to diameter growth without considering fructification as a strong carbon sink.The aim of this research project is to investigate the effects of fructification and coning under different water availability conditions on the diameter growth of important native forest tree species. By drawing on an extensive tree ring archive with data from the Chair of Forest Growth at the University of Freiburg in combination with further data from the State Institute of Forestry and Forest Management in Bavaria, a unique Southern German data pool is available to clarify the interaction of drought stress and fructification during diameter growth. The tree ring width is modelled with mixed generalised additive regression models (GAMMs) as a function of long-term flowering data and meteorological weather data.In addition, combined effects on wood anatomy will be investigated on European beech (Fagus sylvatica), the most important deciduous tree species in terms of area, beech, as an example. For this purpose, thin sections will be made at the microtome and the wood anatomy will be quantitatively evaluated by image analysis.Combining these methods will lead to a deeper understanding of the interactions of intrinsic and extrinsic effects on tree growth.

• DFG Programme: Research Grants