Study on the Population Structure Changes of Pinus massoniana Secondary Forest Cultivation and Transformation in Thousand-isle Lake
This paper aims to analyze the dynamic changes in stand density,tree species structures,and spatial lay-out of Pinus massoniana secondary forest nurturing and transformation.The effectiveness of Pinus massoniana secondary forest transformation was evaluated.Five typical plots of Pinus massoniana natural secondary forest transformation in Thousand-isle Lake were selected as the research objects.In 2008,each plot of 30m × 30m was set up before the implementation of forest stand transformation.In the same year,thinning was carried out in win-ter and replanting was carried out in the following year's Spring Festival.By 2023,restoration monitoring was conducted to investigate the growth of the forest stand before and after forest stand transformation.The important values of tree species were obtained,and spatial structures such as diameter,tree height composition,community mixing degree,size ratio,and angular scale were analyzed.The results showed that ① Pinus massoniana seconda-ry middle-aged forest in Thousand-isle Lake area was felled and replanted with broad-leaved tree species.After 14 years of growth,the stand density increased by 72.88％.② After forest stand transformation,the importance value of Pinus massoniana decreased from 61.308 to 26.754,while the importance value of other evergreen coniferous tree species also decreased synchronously.Both evergreen and deciduous broad-leaved tree species increased to a certain extent,and the importance value of Schima superba and Lithocarpus glaber increased by 6.81％;The im-portant value of shrubs such as Loropetalum chinense and Quercus serrata,as well as small broad-leaved trees,in-creased by 84.81％.③ The community diameter distribution characteristics of Pinus massoniana in the 14th year of nurturing and replanting show an L-shaped pattern,with a tower shaped number of individuals at the height level.There are many young trees in the lower layers,and the compound layer structure is obvious.④ The aver-age degree of mixing before nurturing was 0.42.After nurturing,the degree of mixing increased to 0.72.Due to the increase of dominant trees and the growth of replanted broad-leaved trees,the size ratio differentiation of the com-munity is significant.The average angular scale of the community decreased from 0.59 before nurturing to 0.356 after nurturing,transitioning from clustered distribution to uniform distribution.Intercutting and replanting of broad-leaved tree species in the Pinus massoniana secondary forest is beneficial for improving forest stand struc-tures,increasing forest stand productivity and biodiversity.In the future,the Pinus massoniana secondary forest in Thousand-isle Lake may be characterized by a mixture of coniferous and broad-leaved tree species,combined with small trees and shrubs,to construct a layered forest direction for succession.
Pinus massonianamixed coniferous and broad-leafnative tree speciescompound layersspatial structures of forest standimportant valueThousand-isle Lake
万方数据
维普
