Die buche (Fagus sylvatica L.) - Ein waldbaum ohne zukunft im südlichen Mitteleuropa?

Since the beginning of industrialisation the global mean surface temperature has increased and, as a consequence, the amount and distribution of precipitation have changed. The impact of this global climate change is largest in the continental regions of the Northern Hemisphere. As a consequence climate change in southern Germany is more pronounced compared to the global trend (Abb. 2 to 4). According to results from regional climate models this development will continue during the next decades and will lead to hot and dry summers whereas the spring will become wetter causing severe flooding events. European beech (Fagus sylvatica L.), one of the most important forest tree species in southern Germany, is particularly affected by the increase of periods of drought in summer and periods of heavy rain in fall and spring with oxygen depletion in the soil (Abb. 6 to 8). The drought- and flooding-sensitive beech already now shows reduced growth and reduced competitive capacity especially of the seedlings at extreme sites. These negative effects are supposed to be continued and further extended by the changing climate during the next decades. The competitive capacity of beech will further be reduced by the limited capability of this species compared to other forest trees to take advantage from the increasing atmospheric CO₂ content (Abb. 5). In contrast to these results from investigations by different disciplines of natural sciences, forest political decisions in southern Germany one-sided supported and still support the use of beech. The sylvicultural practices resulting from these political decisions will negatively affect the sustainability of forest development in southern Germany. The current action requirements and research needs are discussed.