Slopewash, surface runoff and fine-litter transport in forest and landslide scars in humid-tropical steeplands, luquillo experimental forest, Puerto Rico

• Published in: Earth surface processes and landforms Vol. 24; no. 6; pp. 481 - 502
• Main Authors: Larsen, Matthew C., Torres-Sánchez, Angel J., Concepción, Iris M.
• Format: Journal Article
• Language: English
• Published: Chichester, UK John Wiley & Sons, Ltd 01.06.1999; Wiley
• Subjects: Bgi / Prodig; Earth sciences; Earth, ocean, space; Exact sciences and technology; fine-litter transport; Geomorphology; Geomorphology, landform evolution; humid tropics; landslides; Luquillo Experimental Forest; Physical geography; Puerto Rico; rainfall; Slopes; slopewash; steeplands; surface runoff; Surficial geology; Puerto Rico; Antilles; Greater Antilles; West Indies; rainfall; landslides; tropical zone; runoff; transport; soil erosion; forests; Caribbean region; Precipitation; Litter; Rill wash; Slope gradient; Tropical zone; Forest; Landslide; Leaching; Field experiment; Sediment transport; Slope
• ISSN: 0197-9337; 1096-9837
• DOI: 10.1002/(SICI)1096-9837(199906)24:6<481::AID-ESP967>3.0.CO;2-G

Rainfall, slopewash (the erosion of soil particles), surface runoff and fine‐litter transport 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 silstone in subtropical rain (tanonuco) forest with vegetation recovering from Hurricane Hugo (1989), and (2) Tertiary quartz diorite in subtropical lower mantone 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 per cent 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. Copyright © 1999 John Wiley & Sons, Ltd.