Site Classification And Evaluation Of Larix Kaempferi (Lamb.)Carr. In Northern Sub-tropical Medium High Area

In order to provide theory support of choosing the most productive tree species, proposing appropriate forest cultivation measures, estimating forest management benefit, reducing timber production cost and forest investment. Site type of artifical forest of Larix kaempferi was devided in north sub-tropical Medium high area. Forestedland and non-rorestedland could be evaluated together. The results were as follows:1. Reaserch of site classificationUsing quantification theoryⅠ, and judge factor contribution according to the partial correlation, coefficients variance and scoring range as three main indexes. It is concluded that altitude, slope degree and thickness of soil layer are the dominant site factors, slope position and directin are secondly dominant site factors in Northern sub-tropical Medium high area. Forty eight site types were devided on the basis of comprehensive factors, classification and combination of dominant factors.2. Formation of quantitative site quality score tableThe quantitative site index equation is construducted using quantitative theoryⅠ. Transform the quantitative site index equation into quantitative site quality score table. Both of them have passed chi-square test, it is showed that they can be used in practice. Using the quantitative site quality score table can evaluate forest land, non-forest land and suitable forests land uniformly. The forty site types were devided into four site quality classes: excellent, good, middle and poor.3. Formation of site index tableRrgression function between stand average tree height and dominant tree height was constructed using the latest second-class investigation data of forest management. Transform stand average tree height into dominant tree height according to the regression function, then fit site index curve by the dominant tree height values. Site index curves and site index table were established by using of ratio adjustment.4. Application of soil nutrient in site evaluation Site index is positive correlation with available N, P, K, total N, P, K, OM; but negative correlation with PH. The regression function of site index was obtained by regression analysis using altitude , soil thickness, slope position, slope direction, slope degree, available N, P, K, total N, P, K, OM and PH. Site index can be calculated conveniently on the basis of regression function.