Comparing german and bulgarian provenances of european beech (FAGUS SYLVATICA l.) regarding survival, growth and ecodistance

As a response to global warming-related increase of temperature and drought, tree species react with reduction of growth and vitality. This is also valid for the drought-sensitive European beech, a major broadleaf species in Europe. One way of studying the possibilities of adaptation of this species to the expected changes is transferring beech reproductive material from wetter and colder to drier and warmer areas. Within this transfer experiment five German and three Bulgarian beech provenances with mean annual precipitation (MAP) amounts of 700 – 1004 mm at origin were planted at three trial sites in Bulgaria (MAP 573 – 811 mm). The study was conducted during the first three years after the provenance trials (PT) were established. At the most xeric site, massive mortality rates for beech of both German and Bulgarian provenances were observed. Hence, MAP < ~580 mm or an Ellenberg quotient (EQ) by ~38 leads to high losses of European beech rejuvenation. Furthermore, it is likely that in lower- altitude regions in Bulgaria beech will face a high extinction risk at the end of the century. In the 3-year study period the trees of Bulgarian provenances were taller than the German ones, which is a sign of a better adaptation