Project

KROOF3B: To the point of failure-water transport along SPAC

Forests are of great economic and ecological importance. In Europe, like in many regions worldwide, intensities and frequencies of heatwaves and drought events are expected to increase in near future, with negative impacts on growth and survival of trees.

The project is carried out in frame of the “Kranzberg Roof Project” (KROOF), which has been initiated in 2013, and aims at understanding how mature trees react to extreme drought. Therefore, in a mixed stand of European beech and Norway spruce, summer precipitation was excluded from 2014 to 2019 on defined plots by means of rainout-shelters. In summer 2019, plots were re-watered. Now, in the third phase, previously drought-treated and re-watered trees will be exposed to a new, potentially lethal drought, as will trees which have not experienced severe drought stress before.

The aim of this project is to understand if previously stressed trees have acclimated and thus are less susceptible to drought or if, vice versa, they are even more vulnerable due to legacy effects. Therefore, various hydraulic parameters and processes along the SPAC will be constantly monitored on trees subjected for the first and second time, respectively, to drought stress, as well as on neighboring control trees. In addition to measurements on adult trees, a similar set of measurements will be carried out on juvenile trees to detect possible ontogenetic differences.

This study will provide new insights into the sequence of processes during drought and help to better understand mechanisms involved in drought-induced tree mortality. Thereby, the KRoof concept provides the unique opportunity to study drought stress response in mature trees. The project is carried out in cooperation with the TU Munich (Ecophysiology of Plants, Thorsten Grams).