[Dynamics of litters in artificial restoration process of subalpine coniferous forest]

By adopting the concept of space as a substitute for time and taking the primitive subalpine coniferous forests as a reference, this paper investigated the forest litters in 10, 30, 40, 50 and 60-years subalpine Picea asperata stands to study the development process of litters in subalpine coniferous plantations with different restoration stages. The difference in litter development in artificial and natural stands was also discussed. The results indicated that in Picea asperata plantations with different ages, the litter pool on forest floor and the nutrient storage and maximum moisture holding capacity of litters showed a general trend of decrease at their earlier restoration stages, and of increase at the later stages. The trend of increase reached the maximum around 50 years of restoration, and then gradually leveled off or even slightly decreased. The observed litter pool (70.21 x 10(3) kg x hm(-2)), nutrient storage (4.73 x 10(3) kg x hm(-2)) and maximum moisture holding capacity (89.98 x 10(3) kg x hm(-2)) of 60-years plantations were considerably small, only accounted for 48.40%, 46.79% and 46.99% of the primitive forests, respectively. After 40 years of restoration, both artificial stands and naturally regenerated secondary forests showed similarity in litter dynamics, annual litterfall, and amount of annual nutrient returning to the soils, while a big difference in litter components, litter pool and structure on the forest floor, nutrient storage, and maximum moisture holding capacity. The difference which accounts for the difference in ecological functioning of the subalpine coniferous plantations lagging behind that of the secondary forests might be mainly caused by the less species diversity of the former.