Litterfall production, decomposition and nutrient use efficiency varies with tropical forest types in Xishuangbanna, SW China: a 10-year study

Litterfall production, decomposition and nutrient use efficiency in three different tropical forest ecosystems in SW China were studied for 10 years. Annual mean litterfall production in tropical seasonal forest (TSF) (9.47 +/- 1.65 Mg ha(-1)) was similar to that in man-made tropical forest (MTF) (9.23 +/- 1.29 Mg ha(-1)) (P > 0.05) but both were significantly lower than that in secondary tropical forest (STF) (12.96 +/- 1.71 Mg ha(-1)) (P < 0.05). The annual variation of litterfall was greater in TSF (17.4%, P < 0.05) than in MTF (14.0%) or STF (13.2%). The annual mean decomposition rate of litterfall increased followed the order of MTF (2.72) < TSF (3.15) < STF (3.50) (P < 0.05), which was not correlated with annual precipitation or annual mean temperature, but was rather related to litter quality. The nutrient use efficiency was found to be element-dependent and to vary significantly among the three forest types (P < 0.05). These results indicate that litterfall production and decomposition rates in different tropical forest systems are related to plant species composition and are influenced strongly by coexisting species and their life stage (age) but less so by the species richness. Constructing multi-species and multistory man-made tropical forest is an effective way to enhance biological productivity and maintain soil nutrients on degraded tropical land.