Woody debris is an ecologically important component of forests as well as a potentially large contributor to the carbonpool of forested terrestrial ecosystems. We characterized coarse woody debris, fine woody debris, litter, and duff bio-mass at 24 sites along an elevation gradient in northeastern Puerto Rico. These sites are representative of eight matureforest types that include Elfin woodland, Sierra palmPrestoea montana, Palo ColoradoCyrilla racemosa, TabonucoDacryodes excelsa, lowland moist, lowland dry, fresh waterPterocarpusswamps, and flooded mangrove forests. Weexpected the amount and composition of both woody debris and forest floor components to vary by forest type. Wehypothesized mid- to upper-elevation forests, exhibiting the greatest basal area and amount of aboveground biomass,would have the greatest amounts of woody debris. In addition we expected the fine woody debris (wood < 7.60 cmdiameter), litter, and duff fractions to be an important source of organic matter in some forest types, representinga significant percentage of total woody debris. We found significant differences in mean total woody debris, coarsewoody debris, and fine woody debris among forest types along the elevation gradient. The mean total woody debriswas significantly greater in the Palo Colorado forest, than the low-elevation Dry (14.79 Mg ha–1) and highest eleva-tion Elfin (17.38 Mg ha–1) forests, with the other forest types containing intermediate amounts of woody debris.In addition, the total fine woody debris fraction was an important component of total carbon storage, representing22–56% of total carbon stored in each forest.