Study On Health Assessment Of Ledum-Larix Gmelinii In Cold-temperate Zone

To establish a health assessment indicators system of Ledum-Larix gmelinii of Cold-temperate Zone at stand level, assess the status of health of Ledum-Larix gmelinii and provide scientific basis for the area of Great Xing'an Mountains , this research measured the indicators by making field survey and setting sampel plots with territorial Ledum-Larix gmelinii of Gen he forest bureau of Inner Mongolia for experimental object.It filtered indicators ,determined the weight ,built assessment model ,divide health level of Ledum-Larix gmelinii into 4 class and finished health assessment with method of principal component analysis and Cluster analysis for the original forest, shelterwood cutting forest and clear cutting forest of Ledum - Larix gmelinii forest in the study area . The results showed:(1) It fixed 19 import indicators for Ledum-Larix gmelinii forest health from stand productivity, soil nutrients, stand structure, resistance and resilience four-part's . And these indicators could initially established the health indicators system of Ledum-Larix gmelinii in Great Xing'an Mountains. It filtered 8 principal component with method of principal component analysis filtering ,which were assessment indicators of Ledum-Larix gmelinii forest .The indicators were comprehensive, resilience, pests, plant species diversity, fire disturbance, reasonable structure, soil nutrients and natural disturbances.(2) Health level of Ledum - Larix gmelinii divided into four classes. They wereâ… level of excellent,â…¡level of good,â…¢level of medium,â…£level of poor. In Ledum-Larix gmelinii, 6 sample plots of original forest wereâ… level of excellent ,which accounted for 33.33 percent; 6 sample plots of gradual cutting forest wereâ…¡level of good, which accounted for 33.33 percent; in 6 sample plots of clear cutting forest, 2 sample plots wasâ…¢level of medium, other 4 sample plots wasâ…£level of Poor, which accounted for 11.12 percent and 22.22 percent. This can be drawn: forest health condition of Ledum - Larix gmelinii shows good overall at present, but there is still certain forest area of poor health condition of the problem.(3) Health index of the original forest was the highest and health condition was the best, which showed that forest growing under natural conditions whose structure was the most stable, whose vitality, resistance and sustainability were all the most strong. Health level of the gradual-cutting forest was second only to the original forest but higher than the cl.ear- cutting forest. There are two health status of the clear-cutting forest in the study area, of which two- third forests were in poor health, of which one-third forests were in sub-health stands at present ,but overall health level of the clear-cutting forest was the lowest.