Composition and spatio-temporal distribution of tree seedlings in an evergreen broad-leaved forest in the Ailao Mountains, Yunnan

Ailao Mountain National Nature Reserve covers 504 km(2) and is one of the largest tracts of evergreen broad-leaved forests in China. A 6-ha plot was established in the reserve in 2008 for the purpose of monitoring long-term dynamics of the forest. Tree seedlings were sampled in this plot to understand their composition and spatio-temporal distribution. Five of the top 10 seedling species in terms of importance values were the same as 6 of the top 10 adult tree species with the highest importance values. Both abundance and species richness of tree seedlings dropped between the end of the rainy season and the end of dry season, likely due to drought stress. Seedlings in canopy gaps were richer in species, more abundant in terms of density, and experienced lower mortality as compared to those under the forest canopy, suggesting that forest gaps facilitate the recruitment of seedlings in the forest.