Study On Sustainable Management Target Structure Of Betula Platyphylla-Larix Gmelini Forest

This study takes the Betula platyphylla-Larix gmelini forest in the Greater Khingan Mountains of Inner Mongolia as the main research object,from the perspective of rational management of natural forests,through the analysis of the non-spatial structure and spatial structure characteristics of the Betula platyphylla-Larix gmelini forest,to understand the forest According to the status quo of internal structure,the sustainable management target structure of the Betula platyphylla-Larix gmelini forest is determined.The main contents and assumptions of the research are as follows:1.The characteristics of stand non-spatial structure and spatial structure were analyzed,Larix gmelini accounts for a larger proportion than that of Betula platyphylla,and Larix gmelini is the dominant tree species;the stand diameter distribution curves are in the form of inverted"J"curves;accumulation structure On the one hand,the stand volume of Larix olgensis is larger than that of Betula platyphylla,and the gradual cutting of Larix olgensis forest accounts for the largest proportion,accounting for 90%of the total volume of the plot;Analysis of the characteristics of forest stand spatial structure:the three forest stands are in an aggregated distribution state as a whole;the clear cut forest in the original forest is in a moderately mixed state,while the gradual cut forest is in a weakly mixed state;Close to the mean state.2.The influence of spatial structure on stand growth was analyzed,when the angular scale is 0.5,the stand is in a random distribution state,and the diameter at breast height growth is the largest;the greater the degree of mixing,the greater the average growth of stand diameter at breast height,and the intensity of mixed It has a promoting effect on the growth of the forest stand;when the size ratio is 0.5,that is,the stand is in a moderate state and the DBH growth is the largest.3.From the ecological benefits and the integrity of forest ecosystem comprehensive consideration,Determine the the sustainable management target structure and standard of the Betula platyphylla-Larix gmelini forest stand:the ratio of conifers to broad-leaved trees in the Betula platyphylla-Larix gmelini forest should be between 7:3-9:1;the diameter distribution should be an inverted"J"curve;Keep the value between 1.2-1.7;the target accumulation ratio of small,medium and large diameter class is 2:3:5;the reasonable operating density range of small,the reasonable management density of stand was 1837-2934 hm^-2;the angular scale is between 0.475-0.517,and the forest is divided into a random distribution state;the degree of mixing reaches 0.75 or more,and the larger the better;the size ratio is the most in the mean state and the least inferior state status.