Classification Of Forest Sites And Evaluation Of Building Timber Forests Dominated By Pinus Tabulaeforims In Liaodong Mountain Areas

This paper took the Pinus tabulaeformis plantation in low mountainous upland region of eastern Liaoning province as the research object.Based on the data of temporary sample plots of Pinus tabulaeformis plantation under different site conditions,more than 100 parsing wood plots,and more than 20,000 sample plots of second-class inventory for Pinus tabulaeformis plantation in montane regions of eastern Liaoning Province.This paper carried out research on the classification of site types and evaluation of site quality of Pinus tabulaeformis timber forest in montane regions of eastern Liaoning Province.We expected to provide theoretical basis and technical support for the scientific construction and rational management of Pinus tabulaeformis timber forest in montane regions of eastern Liaoning Province.The conclusions were as follows:First,based on the statistics and analysis of forestry resource survey of Pinus tabulaeformis plantation in over 20000 blocks of Liaodong mountain area,the total area of Pinus tabulaeformis plantation in Liaodong mountain area is 48957.5hm~2,including Benxi9588.4hm~2,Dandong 3991.8hm~2 and Fushun 35377.3hm~2.Most of the existing artificial forests of Pinus tabulaeformis in Liaodong mountain area are nearly maturing forests,which account for 54%of the total area of Pinus tabulaeformis plantation.Linked to ArcGIS geographic information system,the area distribution map and age group distribution map of Pinus tabulaeformis plantations in Liaodong mountain area were plotted,which provided scientific map materials for visually and clearly understanding the distribution of Pinus tabulaeformis plantations in Liaodong mountain area.Second,through market demand research and production practice convenient requirements,combined with the requirements of forest inventory of Liaoning Province,according to Larix kaempeferi timber forest by age group diameter division standard,and the comparison of the growth process of Larix kaempeferi and Pinus tabulaeformis plantation analysis,put forward the division standard of Pinus tabulaeformis building timber forest in Liaodong mountainous area.According to the four age groups of young,middle-aged,near mature and mature forests,the DBH grading standard of 3 sizes of small diameter,medium diameter and large diameter timber was established.Third,based on the data of more than 100 pieces of temporary plots of Pinus tabulaeformis plantation and more than 100 analytic trees data,the site index table of Pinus tabulaeformis stands in Liaodong mountainous area was compiled.Chi-square test showed that the site index table could accurately reflect the growth process of Pinus tabulaeformis.By using the quantitative theory I method,combined with the site index table of Pinus tabulaeformis plantation and soil texture,soil thickness,slope angle,slope position,slope direction,litter layer thickness and humus layer thickness 7 major site factors,screening out three highest contribution rate dominant factors to the growth process of Pinus tabulaeformis including slope direction,slope angle and soil thickness.According to the method of classification and combination,the forest site types of Pinus tabulaeformis in Liaodong mountain area are divided into 36 site types.Based on ArcGIS geographic information system,the site type distribution map of Pinus tabulaeformis building timber forest in Liaodong mountain area was plotted.Pinus tabulaeformis plantations in Liaodong mountain area is mainly distributed in 3 site types,including medium thickness soil layer which located in shady slope and dip slope,medium thickness soil layer which located in shady slope and steep slope and medium thickness soil layer which located in sunny slope and dip slope,accounting for 57%of the total area.Fourth,The quantification theory I method was used to calculate the scores of all the site factors,and a site quality score table for Pinus tabulaeformis timber forest in montane regions of eastern Liaoning Province was compiled,quantification prediction equation of site quality was constructed,and a site quality grade evaluation table was compiled based on the score range.There were five grades of site quality for Pinus tabulaeformis timber forest in montane regions of eastern Liaoning Province,which were represented by the Roman letters I,II,III,IV,and V,respectively.In order to correspond with the standards for the classification of the diameters of the age groups of the Pinus tabulaeformis timber forest in montane regions of eastern Liaoning Province,the Richard equation was used to fit the height-breast diameter growth curve of Pinus tabulaeformis plantation in montane regions of eastern Liaoning Province.The site quality grade evaluation table of the Pinus tabulaeformis timber forest in montane regions of eastern Liaoning Province was constructed.Site quality DBH grade evaluation showed that grades I and II could be used to produce large-diameter materials,grade III could only produce medium-diameter materials,grade IV could produce medium-diameter and small-diameter materials,and grade V could only produce small-diameter materials in montane regions of eastern Liaoning Province.Based on the ArcGIS geographic information system platform,the distribution map of the quality grade of Pinus tabulaeformis timber forest in the eastern mountainous region of Liaoning Province was plotted.The site quality of Pinus tabulaeformis timber forest in the eastern mountainous region of Liaoning Province was mostly Grade II and Grade III,the number of Grade I and Grade IV plot was few and there was no Grade V plot.