Ecological Functions Of Forest Floor In Forest Ecosystems In Beijing Mountain Area

This research takes three typical planted forest floor in Beijing mountainous area,by studying on three typical planted forest floor,the carbon and the nutrient pool analysis,water retaining capacity,the function of the water and soil conservation,the analysis obtains three kind of forest floor ecology function the similarities and differences,and the innovative research is on allelochemicals to three kinds of forest floor and allelopathy effect between them,the analysis has drawn the preliminary conclusion to provide the feasible suggestion on three kinds of trees types mixes the junction. The paper main results are as follows:The litter total storage capacity of three typical planted forest are different,the order is:the Pinus tabulaeformis forest> the Robinia pseudoacacia forest> the Platycladus orientalis forest.The nutrient of the Pinus tabulaeformis,the Robinia pseudoacacia,the Platycladus orientalis,three kind of planted forest floor take N as highest, P is lowest.The surface nutrient cycling rate with withers and falls the nutrient year restore quantity and forest floor nutrient pool ratio indicated that Pinus tabulaeformis forest surface N and the K cycling rate is biggest,the P cycling rate maximum value (1.48) appears in the Platycladus orientalis forest. The Pinus tabulaeformis forest forest floor carbon reserves is highest, is bigger than the Robinia pseudoacacia and the Platycladus orientalis forest,but Platycladus orientalis's carbon cycling rate compares the Pinus tabulaeformis and the Robinia pseudoacacia forest to be slightly high.The maximum water capacity of the Pinus tabulaeformis,the Robinia pseudoacaci,the Platycladus orientalis forest floor are different. The maximum water capacity of Robinia pseudoacacia is highest, the Platycladus orientalis to be smallest. The rate of maximum water capacity is in turn:the Robinia pseudoacacia> the Platycladus orientalis> the Pinus tabulaeformi.Semi-decomposition litter and undecomposition litter reached saturation in 8h or 10h,on the regression analysis between each water capacity to 0.5-24h and the soaking time relations,obtains in this time interval between the water capacity and the immersion time has the following relations:the relationship of water holding capacity and soaking time is Q=aln(t)+b.In first half-hour,the absorption rate is the largest,the rate was obviously slowed down after 4 h,the relationship of absorption rate and immersion time is V= ktn.The modified interception amount of three kind of forest litter presents the same change rule,that is undecomposition litter to be bigger than semi-decomposition litter.The litter of Robinia pseudoacacia forest is the biggest.With the increase of the slope,it is more obvious to retard effect on runoff and reduce effect on the sediment and runoff yield. The bare land with has withers and falls the cover to produce the sand to produce the current capacity to have the obvious difference.The chemical composition of the Pinus tabulaeformis,the Robinia pseudoacacia,the Platycladus orientalis forest litter mainly to have the mellowness, the alkane,the ester,the phenol,the alkene.The chemical composition of the Pinus tabulaeformis,the Robinia pseudoacacia,,the Platycladus orientalis forest litter to have the similar ingredient, but simultaneously also has respectively the unique chemical composition.Effect of different concentration extract of three forest litter on seed absolute germination percentage, the absolute germination tendency,the root,the embrionic axial length has the varying degree to suppress the influence.