| Site quality evaluation of Korean pine plantation is an important basic work for Korean pine plantation and management.The traditional evaluation of forest site quality takes site index or site grade as an important index,that is,the average height of dominant trees or stand height is used to directly evaluate site quality.Although the two methods in accuracy is higher in forest site quality evaluation of the same age,but every time can only choose as site quality evaluation standard,in order to solve this problem,the advantages of wood synthetical competition index as the site quality evaluation basis,comprehensive competition index includes not only higher basic information of forest tree diameter at breast height and tree,also includes the distance between the trees,covers the more basic information of forest tree growth,so this article use the advantages of wood composite competition index as the basis of forest site quality.Based on the data of Korean pine plantation in 70 sample plots in Jilin Province,this study studied the relationship between stand factors and competitive index of dominant trees in Korean pine plantation.The comprehensive competitive index was used as the site quality evaluation index.Based on the quantitative theory I,the site quality evaluation model of Korean pine plantation was established.The contribution rates of different site factors to the quality of the site were analyzed.The complex correlation coefficient and F test were used to evaluate the accuracy of the model to evaluate the quality of the forest stand of Korean pine plantation.The results are as follows:(1)Put forward the index of comprehensive competition.Through the crown overlap method is adopted,the neighbourhood body and Voronoi diagram method,find the advantages of wood,the corresponding competition analysis of all kinds of dominant tree competition index and stand factors,the relationship between selected competition model of fitting degree is high,the advantage of using this model calculated wood composite competition index,quantification theory model is set up I site quality evaluation,realized the high accuracy of prediction.(2)The quantitative theory model I was applied to establish the site quality evaluation model of Korean pine plantation.The quantitative theoretical model was established by using the topographic factors,stand factors and soil factors in the basic data.The principal component analysis of the site factors showed that different site factors had different effects on the quality assessment of the site.The contribution rate of site factors was ranked as the altitude>aspect>soil thickness>humus thickness>slope.(3)The fitting accuracy of the site quality evaluation model of Korean pine plantation was tested by the re-correlation coefficient and partial correlation coefficient t-test.The results showed that the quantitative theoretical model based on the comprehensive competition index had a good fitting degree,which could not only evaluate the difference of the existing site quality of Korean pine forest,but also provide a theoretical basis for the cultivation of large diameter wood of Korean pine.(4)Site quality evaluation model of Korean pine plantation established in this study was used to evaluate site quality of Korean pine plantation.According to the prediction results,the site quality can be divided into three grades:excellent,good and poor.The evaluation results showed that the sample plots with good neutral quality were characterized by low altitude,thick soil layer,semi-sunny slope and semi-shady slope.The sample plots with good site quality are characterized by medium altitude,medium soil layer thickness,mostly semi-sunny,semi-shady and shady slopes,and thick litter layer.The poor quality of the site is characterized by poor soil fertility,high altitude,and mostly sunny slope.Due to the difference in the distribution of natural conditions,the difference of site types is inevitable.In conclusion,the middle or lower slopes of shady or semi-shady and semi-sunny slopes are suitable sites for cultivating large diameter timber of Korean pine plantation due to their good soil fertility and permeability. |
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