A Study On Decomposition Characterics Of The Korean Pine-broadleaved Forest

This paper is aimed to study several key problems which is associated with litter decomposition in the Korean pine-broadleaved forest in Jiaohe, Jilin of China. The major subjects include the change of decay rates and nutrient dynamics in litters of several common plant species (Pinnus koraiensis, Quercus mongolica, Tilia amurensis and Acer mono) and the occurrence of litter mixture effects and its underlying mechanism of the forest ecosystem. Litter decomposition rates and nutrient dynamics were determined using litterbag burying method.The litter decomposition rates of the broad-leaved tree species are higher than those of conifer. The model analysis suggested that annual leaf decomposition rates (k)0.53for Pinnus koraiensis,0.77for Quercus mongolica,1.60for Tilia amurensis,1.50for Acer mono. The95%decomposition of leaves takes about5to7years for major tree species in the forest During the decomposition, the N concentration and the P concentration in the litters decreased rapidly at the first of decomposition, and then varied insignificantly; The C concentration and the k concentration from the four tree species had net release during decaying; the ratio of carbon (C) to N decreased. The leaf decomposition rates of four major tree species increased at first then decreased in the follow time. The annual mass loss increased over time, but not following a linear pattern. The release rates and dynamic changes of nutrient elements (N, P, K and C) in leaf litter displayed different modes.After395days, the remaining mass of litter of individual species was significantly negatively correlated with initial litter N content. There was significant difference between the observed and expected mass remaining for most litter mixtures, except the Quercusmongolica-Acer mono mixture. Nevertheless, most litter mixtures affected the dynamics of N and P during decomposition. The results show that litter diversity has significant effects on nutrient dynamics, especially for P and N, but not on mass loss rates of most decomposing mixtures, and the effects of mixing are complex. Results showed that the decomposition rates of all the litters were significantly and positively correlated with initial litter N and P concentrations. How it occurred and which mode it is of mixture effects was dependent on the characters of component litters.