Research Note: Effects of leaf decomposition of selected exotic and native tree species on forest soil quality

Abstract

The study evaluated the effects of incorporation and subsequent decomposition of leaves of exotic tree species (Gmelina arborea, Swietenia macrophylla and Tectona grandis) and native tree species (Pterocarpus indicus, Dipterocarpus validus and Parashorea plicata) on the quality of forest soil. Forty-two pots containing an acidic and clayey forest soil and added with fresh leaves on the different tree species were set-up in an open area in Mt. Pangasugan. Retrieval of the first three pots for each treatment was done after two months and the remaining three pots, five months later. Soil samples were collected from each pot and were analyzed for soil respiration rate, pH, OM, total N and available P. Findings showed that in general the exotic tree species did not change the soil pH while native species appeared to decrease it. Regardless of tree species, leaf decomposition significantly increased available soil phosphorus. The leaves of the exotic tree species decomposed faster than those of the native tree species.