Study On Structural Characteristics Of Clear-cutting Larix Gmelinii Forest

In this study,clearing-cutting Larix gmelinii forest in Inner Mongolia was taken as the research object,with the original stands as control.The structure of stand diameter from2006 to 2010 were analyzed and discussed,and the following conclusions were drawn:(1)The stand diameter distribution of different tree species in all the clearing-cutting forest showed“J”curve,which represents a stable stand succession.(2)According to the statistical analysis of the cumulative percentage of the number of Larix gmelinii plants in different diameter stages,the results show that the cubic equation:y=ax~3+bx~2+cx+d could be best used in both clearing-cutting and original stands.(3)The reciprocal and logarithmic equations for the relative order of Larix gmelinii diameter for separate plots are too small to fit the quadratic and cubic equations.The R~2 of the logarithmic equations are basically above 0.9.The R~2for reciprocal and logarithmic equations of Larix gmelinii is higher than that of Betula platyphylla Suk,and the R~2 for reciprocal and logarithmic equations of original stands is higher than that of clearing-cutting stands.To a certain extent,the process of succession in clearing-cutting stands is similar to that of the control original stands.(4)We select the plots with the lowest R~2 to conduct X~2 test.The results showed that the theoretical values of the fitted number of the three equations of the relative logarithm of the diameter of the plot were all checked by N-Par test and X~2 test.This indicates that linear equation,quadratic equation and cubic equation can be used to fit the relative value of the cumulative percentage of the Larix gmelinii.However,the plots with higher R~2 all can be passed through N-Par test and X~2test.(5)According to the crown optical competitive height method and vertical stratification standard of international forest union,we used variance analysis and multiple comparison to study the forest layers.The results showed that the 4 forest layers divided by crown optical competitive height method for clearing-cutting stands and the control original stands have significant difference(P<0.05),and the 3 or 4 forest layers divided by vertical stratification standard of international forest union for clearing-cutting stands and the control original stands have significant difference(P<0.05).This indicated that the process of succession in clearing-cutting stands is same as that of the control original stands according to the view of forest layers.