Study On The Community Structure And Litter Falls In The Pices Schrenkiana Var.tianschanica Forest

Establishing long-term monitoring of forest biodiversity plot is the primary means of ecological research. Currently on forest biological diversity studies of long-term monitoring mainly concentrated in tropical regions, while the study for the temperate coniferous forest is still relatively rare. For the purpose of long-term monitoring dynamics of tree populations, a 6hm2 Picea schrenkiana plot was established in the western Tianshan Mountain. All free-standing trees with DBH(diameter at breast height)≥1 cm were tagged,mapped,measured and identified to species in the plot. This paper aims to give some basic informations for the plot and lay the foundation for future work. The first sample plot survey showed that:there were 1460 woody plant individuals belonging to 7species,7genera and 5families. The number of live individuals was 1292,dead tree was 168. At genus level,the results of floristic characteristics indicated that all the species were temperate elements. Community compostion had obvious dominant species which was Picea schrenkiana. The diameter structure of Picea schrenkiana and Betula tianschanica tended to be normal distribution.There were 17 species of herbs, belonging to 17 genera and 15 families, temperate elements was the mainly composition. The top five Important value species were'Aegopodium alpestre,Impatiens parviflora,Rumex confertus,Stellaria soongarica,Dryopteris filix-mas.Choosing heterogeneous Poisson process null model and using an analytical point pattern method L (r) function and O-ring statistics, this study examined the spatial distribution and their relevance of the major populations of Picea schrenkiana and Betula tianschanica. The results showed that:The individuals of Picea schrenkiana and Betula tianschanica presented mainly as a cluster distribution. The maximum congregate scales of Betula tianschanica were less than Picea schrenkiana,but the maximum congregate intensity was greater than Picea schrenkiana. The correlations between Picea schrenkiana and Betula tianschanica was negative.From August 2008 to July 2009,litters were collected and analyzed every month.the average annual litter production of Picea schrenkiana forest was 2.62t/hm2. There were significant differences of forest litterfall component which the litter production of leaf,branch and bark,flower and fruit,others was 67.38%,19.93%,7.22%,5.48% respectively. The sequence of nutrients returned in form of litter was:Ca (60.82 kg/hm2)>N (25.94 kg/hm2)>K (17.08 kg/hm2)>P (7.44 kg/hm2)>Mg (3.66 kg/hm2) >Fe (1.98 kg/hm2)>Zn (1.38 kg/hm2)>Mn (0.36kg/hm2)>Cu (0.21 kg/hm2)N, P, K, Fe contents of different components of litter were significantly different (p<0.05).