Asian Journal of Advanced Research and Reports

Carbon input to forest ecosystem is mainly from Net Primary Production (NPP), therefore estimating NPP becomes important to understand the global carbon cycle. In this study, allometry for aboveground biomass increment (ΔAGB) and litter trap technique for litterfall (LF) were used for estimating aboveground NPP in Acacia hybrid plantation, Northeast Vietnam. The experiment was conducted in a plot of 300 m² (15×20 m) established in a 21 month old plantation and conducted in a duration of one year. Data were collected in 3 month intervals with a total of five field-measurements. The results indicated that LF and ΔAGB were seasonally dependent. Litterfall was highest (3.38 g m^-2 day^-1) during September-January (winter) and lowest (0.61 g m^-2 day^-1) during March-June (early summer). While ΔAGB was highest (7.7 g m^-2 day^-1) during June-September (summer) and lowest (2.3 g m^-2 day^-1) during January-March (winter). Total LF was 7.27 tones ha^-1 year^-1 and ΔAGB was 18.94 tones ha^-1 year^-1. The total aboveground NPP of Acacia hybrid plantation was 26.31 tones ha^-1 year^-1. It is concluded that LF plays an important role in soil nutrient cycling in Acacia hybrid plantation.