Conversion of secondary broadleaved forest into Chinese fir plantation alters litter production and potential nutrient returns

摘要

Litter production, litter standing crop, and potential nutrient return via litterfall to soil were studied during a 4-year period (January 2004-December 2007) in a Chinese fir (Cunninghamia lanceolata (Lamb.) Hook) plantation and a secondary broadleaved forest in Hunan Province in subtropical China. Mean annual litterfall in the sampling sites varied from 358 g m(-2) in the pure plantation to 669 g m(-2) in the secondary broadleaved forest. Total litterfall followed a bimodal distribution pattern for both forests. Amount of litterfall was also related to the air temperature in both forests. During the period under this study, annual variation in the total litterfall in the pure plantation was significantly higher than that in the secondary broadleaved forest. Litterfall was markedly seasonal in the both forests. Leaf proportions of litterfall in the pure plantation and secondary broadleaved forest were 58.1 and 61.7%, respectively. Total potential nutrient returns to the soil through litterfall in the pure plantation were only 46.2% of those in the secondary broadleaved forest. Total litter standing crop was 913 and 807 g m(-2) in the pure plantation and secondary broadleaved forest, respectively. Our results confirm that conversion from a secondary broadleaved forest into a pure coniferous plantation changes the functioning of the litter system.