Low

Numerous studies have tried to project the effects of climate change on forest productivity and carbon balance through modeling simulations and manipulative experiments. Studies of CO2 fertilization indicate that productivity may generally increase across the Upper Midwest. Warmer temperatures may speed nutrient cycling and increase photosynthetic rates for most tree species. Longer growing seasons could also result in greater growth and productivity of trees and other vegetation, but only if sufficient water and nutrients are available.

Increases in drought, invasive plants, insects, disease, and wildfire are expected to negatively affect forest productivity in some parts of the region. Lags in migration of species to newly suitable habitat may also result in reduced productivity, at least in the short term. However, some of these declines may be offset by the positive effects increased carbon dioxide (CO2) has on photosynthetic rates and water use efficiency, and by a longer growing season.