The Resistance of European Beech (Fagus sylvatica) from the Eastern Natural Limit of Species to Climate Change

In this study, different approaches were used to investigate the vulnerability of beech forests, located at the eastern limit of their natural range, to climate change. To accomplish this, six 2500 m(2) plots were sampled in four European beech forest genetic resources, located in Romania at different altitudinal levels, varying from 230 to 580 m in the Bacau hills and between 650 and 1300 m in the Curvature Carpathian (Brasov region). The analysis of trees phenotypic traits, their radial growth, and the regeneration, did not indicate a vulnerability of the sampled stands to the fluctuations of the environmental factors from the 1950-2014 period. The growth indices of all three populations of Bacau hills are negatively correlated with both June air temperature of current year and September of the previous year. The precipitation amount of September previous year positively influenced the growth indices. The radial growth of plots in Brasov region is slightly linked to the climate. The temperature during the growing season represents a limiting factor for stands that are located outside of the optimal altitudinal species distribution (600-1200 m, in Romania), especially at low altitudes. Our results indicated that a rise of the temperature accompanied by a possible reduction of the precipitations (as is predicted for the coming years) could increase the sensibility of beech forests at lower altitude.