Growing scattered broadleaved tree species in Europe in a changing climate: a review of risks and opportunities

Scattered broadleaved tree species such as ashes (<it>Fraxinus excelsior</it> L. and <it>Fraxinus angustifolia</it> Vahl.), black alder (<it>Alnus glutinosa</it> (L.) Gaertn.), birches (<it>Betula pendula</it> Roth. and <it>Betula pubescens</it> Ehrh.), elms (<it>Ulmus glabra</it> Huds., <it>Ulmus laevis</it> Pall. and <it>Ulmus minor</it> Mill.), limes (<it>Tilia cordata</it> Mill. and <it>Tilia platyphyllos</it> Scop.), maples (<it>Acer campestre</it> L., <it>Acer platanoides</it> L. and <it>Acer pseudoplatanus</it> L.), wild service tree (<it>Sorbus domestica</it> L. and <it>Sorbus torminalis</it> L. Crantz), walnuts (<it>Juglans regia</it> L., <it>Juglans nigra</it> L. and hybrids) and wild cherry (<it>Prunus avium</it> L.) are important components of European forests. Many species have high economic, environmental and social values. Their scattered distributions, exacerbated in many cases by human activity, may make them more vulnerable to climate change. They are likely to have less ability to reproduce or adapt to shifting climate space than more widespread species. The general impacts of climate change on these scattered species are reviewed. Some specific risks and opportunities are highlighted for each species, although there is considerable uncertainty and therefore, difficulty in quantifying many specific risks and/or impacts on scattered broadleaved tree species.