Organic matter accumulation in forest floors is important for carbon and nutrient storage and cycling in forest ecosystems. In the winter of 200l, forest floors were sampled in 7 major forest types of mountainous us areas of Taiwan: Taiwan red pine, Taiwania, China-fir, Crypto, Taiwan red cypress, and natural broadleaf and coniferous forests. Results show that organic matter accumulation ofthese7 forest types increased with an increase in elevation, except the O2 layer of Taiwania and O1 layer of natural coniferous forests which showed an opposite trend. Adding stand age to the regression equations increased the predictive capability of the regression equations based on elevation only. The regression equations developed in this study can be used along with the tree aboveground biomass derived from forest timber surveys to estimate the regional forest aboveground biomass and carbon accumulation in Taiwan.