@article{BoseScherrerCamareroetal.2021, author = {Bose, Arun K. and Scherrer, Daniel and Camarero, j. Julio and Ziche, Daniel and Babst, Flurin and Bigler, Christof and Bolte, Andreas and Dorado-Li{\~n}{\´a}n, Isabel and Etzold, Sophia and Fonti, Patrick and Forrester, David I. and Gavinet, Jordane and Gazol, Antonio and Gonz{\´a}lez de Andr{\´e}s, Ester and Karger, Dirk Nikolaus and Lebourgeois, Francois and L{\´e}vesque, Mathieu and Mart{\´i}nez-Sancho, Elisabet and Menzel, Annette and Neuwirth, Burkhard and Nicolas, Manuel and Sanders, Tanja G. M. and Scharnweber, Tobias and Schr{\"o}der, Jens and Zweifel, Roman and Gessler, Arthur and Rigling, Andreas}, title = {Climate sensitivity and drought seasonality determine post-drought growth recovery of Quercus petraea and Quercus robur in Europe}, series = {Science of The Total Environment}, volume = {784}, journal = {Science of The Total Environment}, publisher = {Elsevier}, issn = {1879-1026}, doi = {10.1016/j.scitotenv.2021.147222}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:eb1-opus-2609}, pages = {13}, year = {2021}, abstract = {Recent studies have identified strong relationships between delayed recovery of tree growth after drought and tree mortality caused by subsequent droughts. These observations raise concerns about forest ecosystem services and post-drought growth recovery given the projected increase in drought frequency and extremes. For quantifying the impact of extreme droughts on tree radial growth, we used a network of tree-ring width data of 1689 trees from 100 sites representing most of the distribution of two drought tolerant, deciduous oak species (Quercus petraea and Quercus robur). We first examined which climatic factors and seasons control growth of the two species and if there is any latitudinal, longitudinal or elevational trend. We then quantified the relative departure from pre-drought growth during droughts, and how fast trees were able to recover the pre-drought growth level. Our results showed that growth was more related to precipitation and climatic water balance (precipitation minus potential evapotranspiration) than to temperature. However, we did not detect any clear latitudinal, longitudinal or elevational trends except a decreasing influence of summer water balance on growth of Q. petraea with latitude. Neither species was able to maintain the pre-drought growth level during droughts. However, both species showed rapid recovery or even growth compensation after summer droughts but displayed slow recovery in response to spring droughts where none of the two species was able to fully recover the pre-drought growth-level over the three post-drought years. Collectively, our results indicate that oaks which are considered resilient to extreme droughts have also shown vulnerability when droughts occurred in spring especially at sites where long-term growth is not significantly correlated with climatic factors. This improved understanding of the role of drought seasonality and climate sensitivity of sites is key to better predict trajectories of post-drought growth recovery in response to the drier climate projected for Europe.}, language = {en} } @article{ZicheRiekRussetal.2021, author = {Ziche, Daniel and Riek, Winfried and Russ, Alexander and Hentschel, Rainer and Martin, Jan}, title = {Water Budgets of Managed Forests in Northeast Germany under Climate Change - Results from a Model Study on Forest Monitoring Sites}, series = {Applied Sciences}, volume = {11}, journal = {Applied Sciences}, number = {5}, publisher = {MDPI}, issn = {2076-3417}, doi = {10.3390/app11052403}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:eb1-opus-2470}, pages = {18}, year = {2021}, abstract = {To develop measures to reduce the vulnerability of forests to drought, it is necessary to estimate specific water balances in sites and to estimate their development with climate change scenarios. We quantified the water balance of seven forest monitoring sites in northeast Germany for the historical time period 1961-2019, and for climate change projections for the time period 2010-2100. We used the LWF-BROOK90 hydrological model forced with historical data, and bias-adjusted data from two models of the fifth phase of the Coupled Model Intercomparison Project (CMIP5) downscaled with regional climate models under the representative concentration pathways (RCPs) 2.6 and 8.5. Site-specific monitoring data were used to give a realistic model input and to calibrate and validate the model. The results revealed significant trends (evapotranspiration, dry days (actual/potential transpiration < 0.7)) toward drier conditions within the historical time period and demonstrate the extreme conditions of 2018 and 2019. Under RCP8.5, both models simulate an increase in evapotranspiration and dry days. The response of precipitation to climate change is ambiguous, with increasing precipitation with one model. Under RCP2.6, both models do not reveal an increase in drought in 2071-2100 compared to 1990-2019. The current temperature increase fits RCP8.5 simulations, suggesting that this scenario is more realistic than RCP2.6}, language = {en} } @article{BoseGesslerBolteetal.2020, author = {Bose, Arun K. and Gessler, Arthur and Bolte, Andreas and Bottero, Alessandra and Buras, Allan and Cailleret, Maxime and Camarero, J. Julio and Haeni, Matthias and Here{\c{s}}, Ana-Maria and Hevia, Andrea and L{\´e}vesque, Mathieu and Linares, Juan C. and Martinez-Vilalta, Jordi and Mat{\´i}as, Luis and Menzel, Annette and S{\´a}nchez-Salguero, Ra{\´u}l and Saurer, Matthias and Vennetier, Michel and Ziche, Daniel and Rigling, Andreas}, title = {Growth and resilience responses of Scots pine to extreme droughts across Europe depend on predrought growth conditions}, series = {Global Change Biology}, volume = {26}, journal = {Global Change Biology}, number = {8}, publisher = {Wiley}, issn = {1365-2486}, doi = {10.1111/gcb.15153}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:eb1-opus-5496}, pages = {4521 -- 4537}, year = {2020}, abstract = {Global climate change is expected to further raise the frequency and severity of extreme events, such as droughts. The effects of extreme droughts on trees are difficult to disentangle given the inherent complexity of drought events (frequency, severity, duration, and timing during the growing season). Besides, drought effects might be modulated by trees' phenotypic variability, which is, in turn, affected by long-term local selective pressures and management legacies. Here we investigated the magnitude and the temporal changes of tree-level resilience (i.e., resistance, recovery, and resilience) to extreme droughts. Moreover, we assessed the tree-, site-, and drought-related factors and their interactions driving the tree-level resilience to extreme droughts. We used a tree-ring network of the widely distributed Scots pine (Pinus sylvestris) along a 2,800 km latitudinal gradient from southern Spain to northern Germany. We found that the resilience to extreme drought decreased in mid-elevation and low productivity sites from 1980-1999 to 2000-2011 likely due to more frequent and severe droughts in the later period. Our study showed that the impact of drought on tree-level resilience was not dependent on its latitudinal location, but rather on the type of sites trees were growing at and on their growth performances (i.e., magnitude and variability of growth) during the predrought period. We found significant interactive effects between drought duration and tree growth prior to drought, suggesting that Scots pine trees with higher magnitude and variability of growth in the long term are more vulnerable to long and severe droughts. Moreover, our results indicate that Scots pine trees that experienced more frequent droughts over the long-term were less resistant to extreme droughts. We, therefore, conclude that the physiological resilience to extreme droughts might be constrained by their growth prior to drought, and that more frequent and longer drought periods may overstrain their potential for acclimation.}, language = {en} }