Response of juvenile progeny of seven forest tree species and their populations to simulated climate change-related stressors, heat, elevated humidity and drought

Abstract

The study aimed to evaluate response and phenotypic plasticity of juvenile progeny of seven forest tree species Pinus sylvestris, Picea abies, Quercus robur, Fraxinus excelsior, Alnus glutinosa, Betula pendula and Populus trem - ula and their populations to climate change-related stressors, simulated in a phytotron – heat and elevated humidity and heat and drought – in comparison to performance in ambient (control) conditions. Treatment effect on sapling morphometric, physiological and biochemical traits was significant except for health condition, transpiration and photosynthetic rates and water use effi - ciency (WUE). Species effect and species-by-treatment interaction were strongly significant in most traits studied, indicating a great inter-specific vari - ability of responses to the applied treatments. Compared to control, stem di - ameter increment was lower for most species following both hot-wet and hot- dry treatments, while treatment impact on height increment was less pro - nounced and sometimes even positive. Drought caused significant defoliation in P. tremula, A. glutinosa and B. pendula , while under hot-wet treatment the defoliation in most species was lower than in control. Following hot dry treat - ment, WUE in P. abies, P. sylvestris and B. pendula was lower than following both hot-wet treatment and control, while in P. tremula, A. glutinosa and Q. robur WUE was higher. This suggests that the latter species are able to main - tain a balance between photosynthesis and transpiration