Changes of Litterfall Amount in Natural Secondary Forests and Chinese Fir Plantations of Different Forest Ages During the Restoration Process

Litterfall is an important manifestation of forest productivity, and its yield is an important factor in regulating the forest productivity and the material cycle of ecosystem. By taking the natural secondary forests and the artificial restored Chinese fir forests at different ages after clear cutting as the research objects, the variation rules and differences of forest productivity between the natural secondary forests and Chinese fir plantations were explored. The results showed that the annual production of litterfall in the natural secondary forests ranged from 5.1 t·hm^-2 to 8.2 t·hm^-2, and increased significantly with the increase of forest age. The annual production of litterfall in Chinese fir plantations ranged from 2.0 t·hm^-2 to 3.1 t·hm^-2, and there was no significant differences between different forest ages. Under the two restoration modes, the litterfall at each forest age stage was dominated by leaf litters, and the composition proportion of litterfall was in the order of leaf>miscellany>branch. At the same forest age stage, the annual production of each component of litterfall in the natural secondary forests was significantly higher than that in Chinese fir plantations. The results showed that compared with the plantations, the natural restoration mode was more beneficial to the increase of litterfall production and the maintenance of forest productivity and soil fertility.