Long-term forest monitoring unravels constant mortality rise in European forests

During the last two decades, Europe has experienced a number of droughts of exceptional duration and intensity, which seem to have left remarkable imprints in the mortality of European forests. However, joint analyses of tree decline and high-resolution drought data have been scarce so far, hence limiting our understanding of tree mortality dynamics at continental scale. Here we make use of the ICP Forest dataset to analyse tree mortality for four major conifers, two major broadleaves, as well as a pooled dataset of minor tree species in Europe. In total, we analysed more than 3 million observations gathered during the last 25 years and employed a high-resolution drought index based on a hydrological model that is able to regularly assess soil moisture anomaly every ten days. Overall, we found significant and species-specific increasing trends in mortality rates accompanied by decreasing soil moisture. A generalized linear model identified previous-year soil moisture anomaly as the most important driver of mortality patterns in European forests. Significant interactions appeared between previous-year soil moisture and stand water regime in conifers, suggesting that conifers growing at productive sites are more vulnerable to drought. We conclude that mortality patterns in European forests are currently reaching a concerning upward trend which could be further accelerated by global change-type droughts.

GEORGE Jan-Peter;  BURKNER Paul Christian;  SANDERS Tanja;  NEUMANN Mathias;  CAMMALLERI Carmelo;  VOGT Juergen;  LANG Mait; 

2023-11-28

WILEY

JRC126966

1435-8603 (online),   

https://publications.jrc.ec.europa.eu/repository/handle/JRC126966,   

10.1111/plb.13469 (online),