Leaf decomposition in a Mexican tropical rain forest

Leaf decomposition in five common species was studied in the Los Tuxtlas tropical rain forest, Veracruz state, Mexico. The species were: Nectandra ambigens (Blake) C. K. Allen, Pseudolmedia oxyphyllaria Donn. Sm, Dussia mexicana (Standl.) Harms, Ficus yoponensis Desvaux and Poulsenia armata (Miq.) Standl. Two experimental studies were done using litter bags, one comparing flat and slope conditions, and the second one in closed canopy and gap conditions. In addition, decomposition was compared between the dry and rainy season. There were significant differences in decomposition rates between species and seasons, but not between zones (flat and gentle slope, and closed forest and gap conditions). The highest decomposition rates were observed for species with high nutrient contents, and also during the rainy season. The data were fitted to three mathematical models derived from the negative simple exponential; the double exponential model for decay was significant. Also, the negative, simple, exponential model which assumes that k is not constant, turned out to be significant for the experiment in closed canopy and gap conditions