A review on plant diversity and forest management of European beech forests

The impact of historical and present drivers on forest biodiversity is poorly understood. A better understanding is mandatory to ensure conservation and appropriate management of biodiversity and ecosystem functions in the face of climate warming and increasing demand for wood products. Here, we assess forest management strategies for maintaining plant biodiversity in Central European beech forests, with a focus on Germany. We show that (1) diversity of the German vascular plant flora increased exponentially during the Holocene reaching 3874 species mainly through apomictic and hybrid speciation. Vascular plant species confined to forests comprise about 10 % of this flora. No loss in vascular plants restricted to forests occured over the past 250 years despite of forest management; (2) the indigenous arboreal flora has a low diversity (64 tree species) compared with other continents due to environmental changes in the last 2 million years; (3) forest management has maintained a high plant diversity in the past. It should be an aim of silviculture to ensure this in the future; and (4) only 22 of the indigenous tree species are commercially used; nine of these commercially used species are threatened by diseases. We introduce the concept of palaeo-neophytes to address genera that existed in Central Europe during the latest Cenozoic. The introduction of species of palaeo-neophytic genera and sub-Mediterranean species is discussed as a measure to buffer negative effects on native species caused by climate change and spread of novel diseases.