Research On The Difference Of Forest Productivity Of Main Site Types In Zhejiang Province

In order to effectively improve the level of forest management and give full play to the potential of forest site productivity,based on the sample plot data of Zhejiang Province based on the seventh and eighth national forest resource continuous investigation data,topographic factors(altitude,slope,aspect,slope position)and Soil factors(thickness of soil layer,thickness of humus,thickness of litter),analyze the geographical distribution characteristics and frequency distribution of the above site factors in Zhejiang Province,and determine the main site types in Zhejiang Province based on the results of forest site classification in Zhejiang Province;adopt biomass The conversion factor continuous function method is used to estimate the forest productivity,and the K-W analysis of variance(ANOVA)is used to analyze the productivity differences of arbor forests on the main site types under different site conditions.The main results indicated that:(1)In terms of the spatial distribution of forest site factors in Zhejiang Province,the altitude showed a gradually decreasing trend from southwest to northeast.The slope is larger in the southwest and smaller in the northeast.Slope aspect,slope position and soil factors were generally uniformly distributed and locally concentrated.In terms of frequency distribution,the elevation generally presents a standard inverse "J" pattern with more distributions at low elevations and less distributions at high elevations.On the whole,the slope is of "N" type,and the flat slope of 0～4° has the highest frequency distribution.In general,the valley and ridge show an inverted "U" shape,which is obviously lower at both ends and higher in the middle.The medium layer thickness,thin layer humus and thin layer litter layer were the most distributed,and all had obvious advantages.(2)16 main site types of forest land were screened out,accounting for 6.6% of all site types;the total number of sample plots was 789,accounting for 28.9% of the total number of forest plots.(3)There were significant differences in the total productivity of arbors on the three site factors,altitude,slope position and soil layer thickness,but no significant differences on the topographic factors,such as slope,aspect.The net productivity of arboreal forest had no significant difference on site factors such as altitude,slope,aspect,slope position and soil layer thickness.(4)The total productivity of different forest types in arbor forests is significantly different on 10 altitude gradients,and the net productivity is significantly different on 8 altitude gradients;the total productivity and net productivity of different forest types in arbor forests vary in slope,aspect,and slope.There are significant differences in the gradients(levels)of site factors such as location and soil thickness.(5)There were significant differences in the total productivity and net productivity of arboreal forests in the subregions,which were mainly reflected in the significant differences between the subregions in the southern mountains of eastern Zhejiang and those in other subregions.There was no significant difference in total productivity among the main site types in the sub-site area.There was a significant difference in the net productivity of the main site types in the North Zhejiang Plain subregion and the Southeast Zhejiang Mountain subregion,but there was no significant difference in the net productivity of other site types in the other subregions.(6)There were significant differences in forest productivity among the main site types,which was mainly reflected in the subregion of the lowland hilly site in eastern Zhejiang-the sloping,steep-semi-sunny slope and medium-thick soil site types with low altitude and other 15 site types.(7)The total productivity and net productivity of pine forest,broad-leaved forest and mixed coniferous and broad-leaved forest have no significant difference in the main site types of different forest land.There is no significant difference in the total productivity of Chinese fir plantations in the main site types,but there is a significant difference in the net productivity.