Comparison of nitrogen content in tree litterfall in three dry dipterocarp forests under different fire regime in northeast Thailand

Abstract

Tree litterfall was measured and nitrogen (N) return by tree litterfall was estimated in three plots, F0, F10, and F35, with different fire histories (protected from fire for 0, 10, and 35 years, respectively) in dry dipterocarp forests (DDF) in northeast Thailand. Annual litterfall was 3.92, 7.13, and 8.79 Mg ha-1, for F0, F10, and F35, respectively. Leaf litter was the main component in all the plots, ranging from 67.4 % to 77.9 %, peaking in the dry season. Other components of the litterfall had no clear seasonality. The N concentration of the tree litterfall increased in the rainy season and decreased in the dry season in all three plots. The N return due to the tree litterfall was estimated to be 33.4, 75.2, and 123.8 kg ha-1, for F0, F10, and F35, respectively. Fire protection increased the N return by tree litterfall, as well as tree litter production in DDF.