Journal Article Summary

This study investigates the increases of atmospheric CO2 and its affect on northern forest productivity and species distributions. Nevertheless, forest response to climate change is generally associated with soil water and nitrogen availability, which in turn, limit tree growth. Therefore, in order to observe the changes a forest undergoes when placed in a warmer and drier climate, a forest productivity/soil process model was linked with a climate model corresponding to a doubling of CO2. Four sites with initially different climates, Shefferville (northern Quebec), Kapuskasing (south-central Ontario), northeastern Minnesota, and northern Maine, were examined in detail. Along with the response to enhanced CO2 levels, soil water-holding capacity and the subsequent positive feedbacks that are initiated as a result of changes in the nitrogen cycle was also observed. Based on the data collected, the greatest changes occurred at the current boreal/cool temperate forest border. Simulated productivity and biomass increased on soils that retained enough water for tree growth, and decreased on soils that did not.