Community Character And Promoting Regeneration Approach Of Typical Picea Wilsonii Forests In Datong River Basin Of Qinhai Province

The maintenance and management of forest ecosystem stability need scientific and reasonable theoretical basis.Community stability is influenced by community structure and function,and is the common effect of community type,community structure,biodiversity and habitat conditions.The Beishan forest area in Datong River Basin is an important water conservation forest in Qilian Mountains and the largest secondary forest area in Qinghai Province,which is listed as the national key ecological public welfare forest.As a major secondary tree species in this forest area,the study of the community types and characteristics is of great significance for the stability and sustainable development of the forest system in this area.The study is taking the community of Picea wilsonii in the area as the object of systematic investigation.The sample site is selected according to the standard forest community investigation method and the methods of R-language Ward clustering analysis,canonical correlation analysis,non-parametric test and regression simulation are used to analyze the community type,species composition,community structure characteristics,species diversity and regeneration characteristics.This paper probes into the response of species diversity and regeneration characteristics of Picea wilsonii to environmental factors,and proposes ways of promoting the regeneration and maintenance of Picea wilsonii forest.The main conclusions of the study are as follows :(1)So 124 species of vascular plants belong to 45 families and 97 genera in the communities of Picea wilsonii in the Donghe River basin of Qinghai Province.The species of herb layer are more.The clustering results of the 24 Picea wilsonii forests in Datong River basin of Qinghai province are classified into 6 communities of Picea wilsonii: Picea wilsonii+ Betula platyphylla-Lonicera tangutica-Carex;Picea wilsonii + Betula albosinensis-Lonicera tangutica-Carex;Picea wilsonii + Pinus tabuliformis-Cotoneaster acutifolius +Lonicera tangutica-Carex;Picea wilsonii + Populus davidiana-Dasiphora glabra-Carex;Picea wilsonii-Cotoneaster acutifolius + Lonicera tangutica-Carex;Picea wilsonii-Euonymus phellomanus-Carex + Fragaria orientalis(2)The community of Picea wilsonii is divided into tree layer,shrub layer and herb layer in the Donghe River basin of Qinghai Province,and no interlayer plants are found.There was no obvious difference in the growth of tree layer among different community types,and the density of each layer was herbaceous layer>Shrub layer>Arbor layer;The average height of shrub layer was positively correlated with the average coverage.The species diversity of Picea wilsonii in the community of Picea wilsonii in this area is significant.The species diversity of grass layer was herbaceous layer>shrub layer>tree layer.Stand density,shrub cover,organic carbon content,total nitrogen content,ammonium nitrogen content and available phosphorus content are the key factors affecting the species diversity of the community of Picea wilsonii.(3)Picea wilsonii is the main group species of Picea wilsonii in this area,and Betula platyphylla,Betula albosinensis,Pinus tabuliformis and Populus davidiana are the codominant species.The population of Picea wilsonii is a growth population,and the populations of Betula platyphylla,Betula albosinensis,Pinus tabuliformis and Populus davidiana are all declining.The seedlings and saplings of Picea wilsonii in the community of Picea wilsonii in this area are deficient and stunted,and the other dominant tree species are in regeneration difficulty.The content of ammonium nitrogen,available phosphorus and p H are the key factors of Picea wilsonii.Artificial promotion of natural regeneration,cleaning of shrub and litter,control of disease and insect pests,creating forest Windows and banning grazing are so as to promote the community regeneration of Picea wilsonii.