吉林汪清杨桦次生林演替与天然更新研究

Forest regeneration process is an important research stage of forest succession, scholars of each country limited their study on impact of each factor and the impact on the environment durning regeneration. This study use the data of long-term forest permanent plots to analysis and some result are achieved: it is a new way to classify the successional stage by the proportion of pioneer species, associated species and top species, the proportion of coniferous broad-leaved tends to a health level as 7:3，the number of update is unsatisfactory. In the mid-successional and late successional canopy density were 0.8 and 0.7 update to achieve a good level，so we should promote update by changing forest canopy density.