Comparative analyses of growth, gas exchange characteristics, and chlorophyll fluorescence of three dominant boreal tree species during the vegetation season in hemiboreal zone, Lithuania

Abstract

Current climate scenarios predicts rising air temperature along with increasing frequency and intensity of summer drought for Central and Eastern Europe during the upcoming decades. Severe drought episodes affect physiological processes in trees such as transpiration, photosynthesis and carbon allocation. This may lead to reduced primary productivity and even forest stand decline. Understanding gas exchange between plants and the atmosphere is important in woody plant research. The different levels of spatiotemporal integration are usually investigated by the tree radial growth, leaf gas exchange measurements, and micrometeorological methods. The study was conducted in Aukstaitija integrated monitoring station, Lithuania. The dominant trees: Betula pendula, Pinus sylvestris and Picea abies were selected for the investigation. Seasonal growth, leaf (needles) gas exchange and chlorophyll fluorescence was measured during the vegetation season and showed relation with meteorological of parameters, especially in the episodes of summer droughts.