Dynamics Of Litterfall Of Evergreen Broad-Leaved Forest On Jinyun Mountain

Litterfall is an important component of forest ecosystems. It acts as a connection between the plant community and soil, and plays a major role in conserving forest water, reducing surface runoff, maintaining fertility of soil, promoting ecosystem nutrient balance and maintaining biological diversity. The evergreen broad-leaved forest is the zonal vegetation type in the subtropics; it is featured by a diverse number of species and high productivity, and meanwhile can provide huge environmental benefits. Studying the quantity and dynamic of litterfall in the evergreen broad-leaved forests will give valuable insights into the nutrient cycles of forest ecosystems, as well as the regeneration of plant population and species coexistence mechanisms.We set 172 litter collectors in a 1 hm2 permanent monitoring plot on Jinyun Mountain and collected litter from January 2014 to December 2015. We firstly investigated the production and composition of the litter. Then, we examined the temporal and spatial patterns of litterfall for the dominant tree species. The main conclusions of this study are as follows:(1) The litter mass was 106.26 kg from 2014 to 2015. The total amount of the litterfall was 12,284.29 kg·hm-2, and the average amount was 6,142.15 kg·hm-2·a-1. Leaf litter accounted for 73.13 % of the total, with branch accounting for 11.49 %, flower and fruit for 9.89 %, others for 4.42 % and bark for 1.07 %, respectively.(2) Monthly dynamic of total litter mass showed a bimodal pattern, and was the same as the dynamic of leaf litter. The peak of the total litter mass was in May and in October or November, while, the minimum of litter mass was collected in January. The peak of the leaf litter was in May and October, and in January the minimum amount of leaf litter was collected. Further, the amount of litterfall of flowers and fruit peaked in November.(3) The spatial distribution of the total litter mass maintained stable from 2014 to 2015.(4) The leaf litter mass was 8,983.08 kg·hm-2 from 2014 to 2015, of which 90.57 % was from evergreen trees and 9.43 % was from deciduous trees. The temporal patterns of leaf litter differed significantly between evergreen trees and deciduous trees.(5) Leaf litter from 13 tree species contributed to 90.97 % of the total leaf litter mass. Relative basal area was significantly positively correlated with the leaf litter mass, and the temporal patterns of leaf litter showed clear differences among these species. In this study, temporal patterns of leaf litter were classified into 3 types: the unimodal, the bimodal and the multi-modal type. The unimodal type included 3 evergreen trees(i.e. Engelhardtia roxburghiana, Symplocos setchuanensis and Adinandra bockiana) and 2 deciduous trees(i.e. Alniphyllum fortunei and Liquidambar formosana). The bimodal type included 5 evergreen tree species: Castanopsis fargesii, Machilus pingii, Elaeocarpus japonicus, Elaeocarpus duclouxii and Castanopsis carlesii. The multi-modal type included 3 evergreen trees: Cunninghamia lanceolate, Pinus massoniana and Prunus spinuosa.