Research On Competitive Situation Of The Forest Mixed With Conifer And Broadleaves In Qingshan Lake Of Zhejiang Province

Competition is an important factor in the growth of trees. The comparison and study on the mixed tree growth and competitive factors not only has great theoretical significance, but also has important practical value.This paper takes Qingshan Lake National Forest Park as the research object, and uses the Ohsawa dominance analysis method to determine dominant species. Using non-perfect competition index (competition index of object compared to the type place average value and competition index of species compared to dominant species) and the complete competition index (variable competitive region competition index- competition degree of the crown and simple index-Hegyi competition index) carry on the competition analysis to the growth of competitive situation of dominant conifer tree species on Qingshan Lake, which proposed three new non-completeness type competition indicators: two-dimensional mean indicators tree indexes (relative growth facade, relative crown projection), three-dimensional mean indicators tree indexes (relative trunk volume, relative crown volume) and four-dimensional mean indicators tree indexes (relative ecological space of the crown ), and four new competition indexes of species compared to dominant species and new variable competitive region competition index- competition degree of the crown, and improve the competition tree selection method simple competition index. The results show that:(1) the relative ecological space of the crown, relative crown volume, relative crown projection can present clear changes with the stand density change, that can better reflect the competitive situation of trees, and relative ecological space of the crown index considers both height and crown factors, to better reflect state of competition of the dominant tree species of the forest mixed with Conifer and Broadleaves in Qingshan Lake.(2) The competition degree of the crown index takes the crown and lighting effects into account to reflect the competitive situation of trees, and the competition degree of the crown of pine is smallest, and the competitive ability is most, followed by pine is C.lanceolata, C. sclerophylla, etc. This law shows basically the same to the average values index ,whichindicated that the competition degree of the crown index is a good indicator of the tree competition description.(3) The intraspecific competition of dominant tree species of the forest mixed with Conifer and Broadleaves in Qingshan Lake greater than interspecific competition, and dominant species showed the aggregated distribution; The intraspecific competition index of S. superba is largest, as 8.275, and the species is most competitive, followed by witch is C.lanceolata, C. glauca, etc.; The intraspecific competition with Q. fabric and L. formosana is the most, indicating that their niche is most similar.(4) There are some differences with the competition analysis to the dominant tree species of the forest mixed with Conifer and Broadleaves in Qingshan Lake using these competition indicators; In the 18 indicators average of the dominant species, the average indicators of P.massoniana is largest, as 1.929, which indicates its comprehensive competitiveness is the strongest; pioneer tree species P.massoniana is in dominant position in the community, indicating that the community has not reached the top stage of succession, but in the succession process.