Plant litter decomposition is a fundamental process that links plant and soil communities through the cycling of carbon and nutrients in temperate forests. Mycorrhizal association, a key plant functional trait, has been shown to heavily influence ecosystem nutrient cycling by modifying nutrient acquisition strategies, litter quality, and soil organic matter dynamics. Recent work has demonstrated that arbuscular mycorrhizal (AM) and ectomycorrhizal (EcM) tree species in temperate forests differ in leaf litter decomposition rates. Yet, we lack an understanding as to whether these differences are driven primarily by aboveground (e.g., leaf litter) or belowground plant inputs (e.g., root litter, root exudates, mycorrhizal tissue). Thus, the overall goal of my research is to disentangle the relative contribution of varying plant inputs to decomposition and soil nutrient dynamics across mycorrhizal types. Specifically, I will be conducting a leaf litter transplant experiment within AM- and EcM-dominated tree stands at Harvard Forest. This summer, I identified five locations that each contain paired AM- and EcM-dominated stands. Within each location, I will establish six 5x5m experimental plots: 1) AM stand with intact litter layer, 2) AM stand with only AM litter, 3) AM stand with only EcM litter, 4) EcM stand with intact litter layer, 5) EcM stand with only AM litter, and 6) EcM with only EcM litter (total n = 30). This experimental design will allow me to isolate the effects of mycorrhizal type and litter source on soil organic matter dynamics. Insights from this work may improve predictions of how species composition influences ecosystem processes within temperate forests, particularly under global change.