Effects of elevated CO2 and different nutrient supplies on wood structure of European beech (Fagus sylvatica) and gray poplar (Populus × canescens)

Abstract

Anatomical responses and annual ring-width of beech and poplar saplings were studied under elevated CO2-concentrations (770/950 ppm) with different nu-trient supplies during two growth periods. At the end of each growth season, saplings were harvested and stem vessel characteristics as well as annual growth-rings were analysed. In both study years, elevated CO2 caused a significant increase in ring width (RW) of beech but not of poplar. However, fertilization increased RW in poplar saplings. In beech total vessel lumen area (TVLA) and vessel density (VD) increased under elevated CO2 and both parameters decreased by fertilization. Poplar saplings grown under elevated CO2 had significantly larger vessels as well as TVLA while fertilization induced reduction in average vessel lumen area (AVLA) and TVLA. Vessel density of poplar showed no significant response to different growth conditions. Altogether, the effects of elevated CO2 and fertilization on anatomical features were independent of each other.