Belowground carbon allocation in forests is poorly understood. Biomass production, root respiration and carbohydrate storage have often been quantified in recent years, but the factors controlling these processes remain unclear. This project will do a comprehensive examination of control and fertilized red pine (Pinus resinosa Ait.) root systems, in order to determine how climate and nutrients influence belowground carbon allocation By combining information on changes in in situ root respiration, total soil respiration, root starch and N concentrations, root growth and climate factors over time, they will construct yearly belowground carbon budgets for control and fertilized red pine in northern Wisconsin. They study will complement a similar study of slash pine in Florida and will be compared to predictions from total soil respiration and ecosystem process models.