[Litterfall amount and its dynamics in urban forest of Shenyang, Northeast China]

Twenty sampling sites were set in the urban forest of Shenyang to continuously observe the amount of forest litterfall and its dynamics in 2005-2007. During the three years, the leaf litters collected in twenty 1 m2 litterfall traps were of 30 tree species, which accounted for 15.5% of the entire tree species in Shenyang, but the individual number and leaf area of the populations accounted for 63.8% and 69.9%, respectively. A significant positive correlation was observed between the leaf litterfall amount and the leaf area of the corresponding tree species, and there was a great difference in the beginning time of the leaf fall between different tree species. The species with earlier beginning time of leaf fall finished their leaf fall earlier, and thus, there was a significant positive correlation between the beginning time of leaf fall and the ending time and duration of leaf fall. The average annual litter production was 4229.0 kg x hm(-2), among which, leaf litterfall was 3397.36 kg x hm(-2), branch litterfall was 463.89 kg x hm(-2), and fruit- and flower litterfall was 367.73 kg x hm(-2), accounting for 80.3%, 11.0%, and 8.7% of the total production, respectively. The seasonal dynamics of the litterfalls showed a single peak, with the maximum appeared in October and accounted for about 50.0% of the total. The large amount of the litterfalls could supply nutrients and energy for urban forest.