Larsen, M.C., Torres-Sánchez, A.J., and Concepción, I.M., 1998, Slopewash, surface runoff, and fine-litter transport in forest and landslide scars in humid-tropical steeplands, Luquillo Experimental Forest, Puerto Rico [abs] EOS, Transactions American Geophysical Union, vol. 80.
Abstract:
Rainfall, slopewash (the erosion of soil particles), surface runoff, and fine-litter transport at humid-tropical steepland
sites in the Luquillo Experimental Forest, Puerto Rico (18? 20' N, 65? 45' W) were measured from 1991 to 1995.
Hillslopes underlain by: 1) Cretaceous tuffaceous sandstone and siltstone in subtropical rain (tabonuco) forest with
vegetation recovering from Hurricane Hugo (1989); and underlain by 2) Tertiary quartz diorite in subtropical lower
montane wet (colorado and dwarf) forest with undisturbed forest canopy were compared to recent landslide scars.
Monthly surface runoff on these very steep hillslopes (24? to 43?) was only 0.2 to 0.5 percent of monthly rainfall.
Slopewash was higher in sandy loam soils whose parent material is quartz diorite (averaging 46 g m-2 a-1) than in
silty-clay loam soils derived from tuffaceous sandstone and siltstone where the average was 9 g m-2 a-1. Annual
slopewash of 100 to 349 g m-2 on the surfaces of two recent, small landslide scars was measured initially but
slopewash decreased to only 3 to 4 g m-2 a-1 by the end of the study. The mean annual mass of fine litter (mainly
leaves and twigs) transported downslope at the forested sites ranged from 5 to 8 g m-2 and was lower at the
tabonuco forest site, where post-Hurricane Hugo recovery is still in progress. Mean annual fine-litter transport was
2.5 g m-2 on the two landslide scars.