Assessing the Contrasting Effects of the Exceptional 2015 Drought on the Carbon Dynamics in Two Norway Spruce Forest Ecosystems

The occurrence of extreme drought poses a severe threat to forest ecosystems and reduces their capability sequester carbon dioxide. This study analysed the impacts central European summer in 2015 on gross primary productivity (GPP) at two Norway spruce sites representing contrasting climatic conditions—cold humid climate Bílý Kříž (CZ-BK1) vs. moderately warm dry Rájec (CZ-RAJ). comparative analyses GPP was based three-year eddy covariance dataset, where 2014 2016 represented years with normal conditions, while characterized by conditions. A significant decline found during year 2015, reaching 14% 6% CZ-BK1 CZ-RAJ, respectively. reduction coincided high ecosystem respiration (Reco) period, especially July August, when several heat waves hit region. Additional period suggested that vapour pressure deficit played more important role than soil volumetric water content both investigated sites, highlighting often neglected importance considering species hydraulic strategy (isohydric anisohydric) impact assessments. indicates vulnerability stress, precipitation equal or smaller atmospheric evaporative demand. Since Europe is currently experiencing large-scale dieback forests lowlands uplands (such as for CZ-RAJ conditions), findings this may help quantitatively assess fate these widespread cultures under future projections, delimitate areas sustainable production.