Abstract:

The study analyzed the characteristics of the canopy growth with different classified stems in natural Larix gmelinii forests and also made the biomass models between the crown width growth and the branch/leaf biomass of a crown. The results showed: (1)In the stands with age of 36-39 a,and density of 983-3 263 trees·hm^-2 as well as the stands with age of 54-61 a,and density among 1 101-2 241 trees·hm^-2,as the stand density increased,the difference of crown width among each classified stem reduced,while the proportion of crown length to tree height and the proportion of crown length to crown width increased; the mean individnal crown volume of dominant trees,average trees and overtopped trees was 22.479,15.296,6.179 and 26.864,11.154,8.192 m³ respectively. (2) In the stands age of 36-39 a the average individual crown biomass of dominant trees,average trees and overtopped trees was 0.008 2,0.004 9,0.000 9 t and the mean ratios of the crown biomass to its above-ground biomass were 18.5%,24.2%,17.3%. However in the forest stands age of 54-61 the biomass and the ratios of the crown biomass to its above-ground biomass were 0.007 9,0.003 8,0.001 4 t and 15.9%,12.0%,20.5% respectively. (3) As for biomass allocation in a crown,proportion of leaf biomass was higher than branch biomass,and the allocation was different among each classified stem. In the forest stands age of 36～39a the branch biomass proportions of dominant trees,mean trees and overtopped trees were 76.6%,74.7%,66.6% and the leaf biomass proportions were 23.4%,25.3%,33.4%. However in the forest stands age of 54-61 a the branch biomass proportions and the leaf biomass proportions were 76.8%,73.3%,71.4%,and 23.2%,26.7%,28.6% respectively. (4)In the forest stands age of 36-39 a the total crown biomass were 4.63-15.61t·hm^-2,in the total crown biomass,the ratios of the leaf biomass and the branch biomass were 74.9% and 25.1%,while in the forest stands age of 54-61 a the crown biomass and the ratios of the leaf biomass and the branch biomass were 3.03-11.08 t·hm^-2 and 73.9% and 26.1% respectively. In the forest stands age of 36-39 a,the proportion of crown biomass to above-ground biomass increased as the stand density rose,while in the forest stands age of 54-61 a the proportion change enhibited a one-peak curve. The proportions of each forest stand were 9.1%-42.9% and 12.4-24.4%.

Key words: Larix gmelinii, natural forest, crown growth, crown biomass, biomass model