European beech (Fagus sylvatica L.) will most likely be threatened by climate change. Therefore, more knowledge of its adaptation potential to changing environmental conditions is required. Several studies showed differences in adaptive traits for beech populations from across Europe, but there is also growing evidence for microevolutionary processes occurring within short geographic distances in this species, or even a lack of local adaptation. Hence, a more regional perspective for adaptation research in beech might be appropriate. Here, we investigated the performance (height, height increment and mortality) and genetic structure based on microsatellite markers of 2400 beech seedlings from provenances growing along a temperature and precipitation gradient in Northern Germany in a common garden experiment. Differences for all traits were found among provenances. Provenances from lower precipitation areas did not perform better than provenances from higher precipitation areas at the common garden site, which was located near the lower precipitation limit of beech. Further, neighboring provenances growing on either sandy or loamy soils showed more different adaptive trait variation than distant provenances. We detected minor genetic structure among provenances and a high genetic diversity within them. Thus, small-scale adaptive trait variation in beech can occur, despite low but significant genetic population structure among provenances.
