Potential impacts of climate change on the distribution of North American trees

Currently predicted change in climate could strongly affect plant distributions during the next century. Here we determine the present-day climatic niches for 130 North American tree species. We then locate the climatic conditions of these niches on maps of predicted future climate, indicating where each species could potentially occur by the end of the century. A major unknown in this work is the extent to which populations of trees will actually track climate shifts through migration. We therefore present two extreme scenarios in which species either move entirely into future climatic niches or do not move out of their current niches. In the full-dispersal scenario, future potential ranges show decreases and increases in size, with an average decrease of 12% and a northward shift of 700 kilometers (km). In the no-dispersal scenario, potential ranges decrease in size by 58% and shift northward by 330 km. Major redistribution pressures appear to be in order under both dispersal scenarios.