The Forest Litter-fall Decomposition Of Successional Stages In The Broadleaved-Korean Pine Mixed Forest

In ecosystem,litter-fall,as the largest source of material and energy,contained all the organic material which formed by up-ground plants and returned to ground,and maintained the ecosystem function.The research had been carried out in the forest litter-fall of successional stages in the broadleaved-Korean pine mixed forest,the station as Liang shui national Nature Reserve during October 2006 to November 2007.The amounts,components and seasonal dynamics of litter and their decomposition,the characteristics of nutrient element release during decomposition had been investigated.Stands of different successional stages have different species composition,leading to significant difference in stands litter.The amount of litter-fall for forest gap,Betulla platyphylla stand and broadleaved-Korean pine mixed forest were 2857.37,2343.93 and 3268.56 kg·hm^-2·yr^-1,respectively.Annual litter amount in our research were within the range of the reported litter amount in Frigid Zone,and lower than the annual litter amount of temperate zone,subtropical and tropic,which indicated that litter amount have zonality. Amount of each composition litter of different stands have diversity in total amount,but litter leaves was the primary composition.Seasonal rhythm of the total amount was similar and had large variations in forest gap and broadleaved-Korean pine mixed forest.The peak of the two types appeared in September,and had a sub-peak in June and July for the rainy condition.The seasonal course of total litter amount in Betulla platyphylla stand is single peak style and the peak value appeared in August and September.The decomposition rates of different stands for Betulla costata litter leaves,Tilla amurensis litter leaves and mixed litter leaves were different.The more advanced of forest community, the quicker of the decomposition rate.The order of loss rate was:gap＜Betulla platyphylla forest＜selection forest＜broadleaved-Korean pine mixed forest,while,the order of decomposition rate of Pinus koraiensis litter leaves was:forest gap＜broadleaved-Korean pine mixed forest＜selection forest.We used Olson model to estimate the time when the same litter leaves decomposed at 50%and 95%need and the K value of litter decomposition index.The fitting models in this experiment were statistical significant.In this study,through there were decomposition release and enrichment process of year round,Nitrogen in all litter leaves appeared enrichment.The result showed that Phosphorus concentration for mixed litter leaves and Tilla amurensis litter leaves of forest gap,Betulla platyphylla forest and broadleaved-Korean pine mixed forest declined,while,which of selection forest raised.Phosphorus concentration of Betulla costata litter leaves all declined in the mass,while Pinus koraiensis litter leaves raised.Potassium concentration of litter leaves in all stands declined except for Pinus koraiensis litter leaves exhibited enrichment in broadleaved-Korean pine mixed forest(increased 0.393g/kg).Carbon concentration and the ratio of C/N of litter leaves in different stands indicated fluctuating property but decreased with the decomposition development.As the higher degree of decomposition for all litter leaves reached,it was different in release rate of nitrogen,but all presented enrichment.It has no orderliness in release rate of Phosphorus,some of which presented net enrichment and others net release.The release rates of Potassium for different litter leaves were different,but all presented net release patterns.