A Study On Spatial Structure And Undergrowth Vegetation Of Larix Principis-rupprechtii Mayr Plantation

By taking Larix principis-rupprechtii Mayr plantation of Sai Hanba mechanical forest farm as research object,different intensities of disturbance plantation(225 trees/hm2,600 trees/hm2,900 trees/hm2,1350 trees/hm2,1800 trees/hm2)and different forest mixed forest——mixed wood,broadleaved mixed forest and coniferous mixed forest.This paper makes a comparative study on tree species composition complexity H (X), species structure complexity H (Y /X) forest community complexity H ( X,Y)and study on tree crown overlap coefficients,neighborhood comparison,uniform angle index and mingling degree. Based on the Researching of stand characteristics and forest Spatial Structure provide theoretical basis and technical support for sustainable management of Larix principis-rupprechtii Mayr plantation.(1)Tree species composition complexity and species structure complexity of mixed wood and broadleaved mixed forest greater than coniferous mixed forest. tree species composition complexity H (X), species structure complexity H (Y /X) of Pinus sylvestnis var. mongolica Litv. and Picea asperata Mast greater than species structure complexity H (Y /X).species structure complexity H (Y /X)of different intensities of disturbance plantation:Pole strength thinning area> intensity intermediate felling area> moderate thinning area>control area>light thinning area. species structure complexity H (Y /X) of different intensities of disturbance plantation: intensity intermediate felling area> pole strength thinning area> moderate thinning area>light thinning area>control area.(2) This paper makes a comparative study on space area of individual tree of different thinning forest and individual tree of control area which shows that intensity intermediate felling area> pole strength thinning area> moderate thinning area>light thinning area>control area. Forest space area utilization degree of individual tree of different thinning forest higher than control area. Growth space competition indicators increase with increasing thinning intensity,but growth space indicators decrease with increasing thinning intensity.(3)Forest space uniform angle index shows that forest average uniform angle index distribution range is 0.25-0.5 of different thinning intensity forest and control area forest which are uniform distribution and random distribution. Forest uniform angle of different thinning intensity forest mainly distribute range is 0.25 which is uniform distribution, secondly,they distribute range is 0.5 which is random distribution. Then,the distribute range are 0 and 0.75 which are quite uniform distribution and non-uniform distribution. The uniform angle index is 1 which has the smallest proportion than others. forest average uniform angle index of mixed wood and coniferous mixed forest are 0.3929 and 0.25.the results show that they are uniform distribution.(4) Reference tree's tree-height neighborhood comparison of different thinning intensity forest locate in inferior position in pole strength thinning area(A)and intensity intermediate felling area(B). Reference tree's tree-height neighborhood comparison of moderate thinning area(C) and light thinning area(D) occupy dominant position and middlebrow status.The proportion of compression state have 58.4% in control area and their average tree-heiight neighborhood comparison are 0.667 that more than 0.5.The result shows that reference trees occupy dominant position from the global aspect.The most of reference trees occupy dominant position in mixed wood. reference trees occupy unstable dominant position in coniferous mixed forest which have larger ratio to Orient middlebrow status.Making a comparative study on diameter at breast height neighborhood comparisonn of different thinning forest show that reference trees locate in inferior position in pole strength thinning area(A)and intensity intermediate felling area(B). reference trees occupy middlebrow status in moderate thinning area(C) and light thinning area(D). reference trees occupy dominant position in control area.Forest crown neighborhood comparisonn of different thinning forest show that reference trees locate in inferior position in pole strength thinning area(A). reference trees occupy middlebrow status in intensity intermediate felling area(B). reference trees occupy stable dominant position in light thinning area(D). reference trees occupy unstable dominant position in control area which have larger ratio to Orient middlebrow status.Reference trees locate in absolute inferior position in mixed wood and their ratio is 71.42%. Reference trees occupy absolute dominant position in coniferous mixed forest.(5) This paper makes a comparative study on undergrowth plant density and plant coverage.The result shows that plant coverage of four different thinning forest respectively higher 2.89,1.56,2.31and 2.41 times than control area. Height of undergrowth vegetation have more than 130cm in pole strength thinning area(A)and intensity intermediate felling area(B). Height of undergrowth vegetation have more than 100cm in moderate thinning area(C). vertical distribution range of undergrowth vegetation would be largen.