The Decomposition of Leaf Litter in Jamaican Montane Rain Forests

(1) The accumulation and decomposition of litter were studied over two separate years in four montane rain forests (Mor Ridge forest, Mull Ridge forest, Wet Slope forest and Gap forest) at c. 1550 m altitude in Jamaica. (2) Mean standing crop of leaf litter ranged from 8.1 to 11.7 t ha-'. Mean decomposition rates for the standing crop of leaf litter at the three sites on level ground were as follows: Gap forest 68% yr-1; Mull Ridge forest 45% yr-1; and Mor Ridge forest 44% yr--'. (3) For freshly-fallen leaves, decomposition varied between species (15 studied) from 27% to >96% yr-1; was not affected by site of collection, but was affected by site of decomposition in one year (of two); was slower in drier periods; was positively correlated with the nitrogen and phosphorus concentrations of mature leaves; and was not significantly correlated with various anatomical features of the leaves. (4) Data for a range of tropical rain forests suggest that the rate of decay of the standing crop of leaf litter parallels the net primary productivity and stature of the forest, irrespective of altitude.