Forest Site Classification And Suitability Of Cunninghamia Lanceolate(Lamb.) Hook In Zhejiang Province

Forest site is the basis of forest growth.Site classification and the suitability analysis of tree species have been indentified as important tools in forestry for the accurate improvement of forest quality.It is useful in scientific forest management,and efficient use of land.It is also of great significance to accurately promote the quality of the project.This paper based on national forest inventory data from 2009 and digital elevation model data from 2009 across Zhejiang Province,classified the forest site types using the method of combing multiple factors and dominant factors and the third theory of quantification,analyzed the suitability of tree species using the Maxent ecological model.The results were as follows:(1)The zoning unit(site area,site region,site sub-region)of the forest site classification system of Zhejiang Province followed the results of “China Forest Site Classification”(1995),and the classifying unit(site type district,group of site type,site type)of the forest site classification system of Zhejiang Province followed the dominant factors.Using the third theory of quantification,the dominant factors were selected in the site sub-region respectively.(2)In northern Zhejiang plains site sub-region,the dominant factors were: slope > soil thickness > humus thickness.In northwestern Zhejiang low hilly site sub-region,the dominant factors were: slope,aspect > humus thickness > soil thickness.In eastern Zhejiang coastal hilly site sub-region,western Zhejiang middle-low mountains site sub-region,eastern Zhejiang low hilly site sub-region,and midwestern Zhejiang site sub-region,the dominant factors all were: aspect,elevation > soil thickmess > slope.In sourtheastern Zhejiang mountainous site sub-region,and sourthwestern Zhejiang mountainous site sub-region,the dominant factors were: aspect > soil thickness > slope.(3)Based on the importance of the dominant factors,the forest site classification system was established.And the forestland in Zhejiang Province was divided into5 site regions,8 site sub-regions,54 site type districts,118 groups of site type and 242 site types.(4)Cunninghamia lanceolate(Lamb.)Hook was taken as the research object in the suitability analysis of tree species.We selected the plots with dominant species of Cunninghamia lanceolate(Lamb.)Hook from NFI data and established the Maxent ecological model with samples location data and the environmental variable data as input variables and the suitability probability of Cunninghamia lanceolate(Lamb.)Hook as output variable to predict the suitable distribution in Zhejiang Province.The results showed that test data and training data AUC were 0.851 and 0.832,which indicated a better forecast.The highly suitable area for Cunninghamia lanceolate(Lamb.)Hook was mainly distributed in the southwestern regions of Zhejiang Province;the moderately suitable areas for Cunninghamia lanceolate(Lamb.)Hook was mainly distributed in the south and southeastern regions of Zhejiang Province;the lowly suitable areas for Cunninghamia lanceolate(Lamb.)Hook was mainly distributed in the central and western regions of Zhejiang Province;the unfavorable areas for Cunninghamia lanceolate(Lamb.)Hook was mainly distributed in northeastern regions of Zhejiang Province,the eastern coastal area,and the part of central Zhejiang Province.(5)Analysing the distribution of suitability for Cunninghamia lanceolate(Lamb.)Hook and forest site classification in Zhejiang Province can be concluded as follows: the unfavorable areas for Cunninghamia lanceolate(Lamb.)Hook was mainly distributed in gentle slope-thick soil-thin humus site type in northern Zhejiang plains site sub-region,and low elevation-gentle shady slope-thick soil site type in eastern Zhejiang coastal hilly site sub-region.The highly suitable area for Cunninghamia lanceolate(Lamb.)Hook was mainly distributed in semi-shady medium slope-medium and thick soil site type,sunny medium slope-medium and thick soil site type in sourtheastern Zhejiang mountainous site sub-region.