Increasing atmospheric carbon dioxide concentrations and nitrogen deposition are affecting biogeochemical cycles in many ecosystems, such as the temperate deciduous forest of the Morgan-Monroe Ameriflux research site in Southern Indiana.  We conducted a fertilization experiment with nitrogen, phosphorus and carbon on sugar maple and white oak to examine belowground processes affected by global climate changes.  Sugar maple and white oak are two dominant tree species in this forest and were chosen for study due to differences in litter quality and primary mycorrhizal associations.  Treatments were applied in a factorial design to 64 plots within the drip line of mature trees.  To simulate wet deposition and the products of fine root decomposition, nutrient additions were dissolved in water prior to application.  Results from the second year of treatment show species specific differences and strong interactions with phosphorus.  Fine root biomass showed a strong interaction between tree species and phosphorus. Sugar maples decreased fine root biomass with nitrogen and phosphorus additions while white oaks increased fine root biomass with nitrogen and phosphorus treatments.  Similarly, soil respiration was significantly higher in sugar maple plots receiving phosphorus.  Soil carbon also increased in response to phosphorus additions.  Ectomycorrhizal abundance increased with carbon additions while ectomycorrhizal diversity, as determined by morphotyping, declined in response to nitrogen and phosphorus additions.  Arbuscular mycorrhizal abundance showed a species specific response to nitrogen and phosphorus.  These results suggest that global climate changes may differentially affect belowground processes as a result of species specific responses.