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Anthropogenic N deposition affects litter decomposition and soil organic matter (SOM) storage through multiple mechanisms. Microbial community responses to long-term N deposition were investigated in a sugar maple-dominated forest in northern Michigan during the 1998–2000 growing seasons. Litter and soil were collected from three fertilized plots (30kg N ha⁻¹y⁻¹) and three control plots. The activities of 10 extracellular enzymes (EEA) were assayed. ANOVA and meta-analysis techniques were used to compare treatment responses. EEA responses to N amendment were greater in litter than in soil (litter mean effect size [d]=0.534 std. dev.; soil d=0.308). Urease, acid phosphatase and glycosidase (β-glucosidase, α-glucosidase, cellobiohydrolase, β-xylosidase) activities increased in both soil and litter; mean responses ranged from 7 to 56%. N-Acetylglucosaminidase activity increased 14% in soil but …