Climate change is likely to drive tree species towards colder and wetter regions of their geographical distribution, a new study has shown. The research, led by the University of Alcalá, in Spain, and including researchers at the University of Birmingham, draws together data from across Europe and North America to show that tree species in the Northern Hemisphere are starting to become denser in colder and wetter regions. The study provides the first quantitative evidence that climate change is driving this change in the numbers of trees of each species across temperate forests on a continental scale. The researchers analysed data from over two million trees, representing 73 species widely distributed across Europe and the United States. …Understanding how forest species are responding to climate change through increasing their density in these more northerly regions is essential for planning ecosystem conservation, management and restoration.