The Key Technologies Of The Natural Uneven-Aged Forest Cutting

In this paper, using the natural spruce-fir mixed forest as the research object, which is located in Jingouling forest farm, Wangqing forestry bureau, Jilin province, stand growth and structure dynamic of more than 20 years for tending spruce-fir forest of different selective cutting intensity.we analysis the diameter structure stands, diameter class structure, species composition and volume Growth in different accumulation levels to design to find the optimal cutting time and provide theoretical basis and technical support for the natural uneven-aged forests.And we also use the fixed sample of Bureau in Changbai Mountain, To divide the nutrition area of each tree in different years by thiessen polygons,obtain the relation between the size class and the volume growth in the unit area.By this method,we can determine the mature of a single tree,and provide guidance for uneven-aged forest management.And the main research results show as follows:1)The stand volume size can be a good judge to determine the developmental stage of stands. The structure and growth in the whole process of succession of the natural spruce-fir mixed forest is a process of gradually too.And in this study,The analysis of the structure and growth in different accumulation levels can be proved the rule very well.2)When the spruce-fir conifer and broadleaf mixed forests in Changbai Mountain stand up to 350～400m3/hm2.accumulation level,which the stand volume growth was just had a maximum, is the best cutting period of forest stand.Because in this period,we can get the wood not only, still can adjust the structure of forest stand diameter.If we the reasonable control of the process, to adjust the structure of the main forest layer constantly, we can to keep the stand accumulation was the biggest and the purpose of long-term stability,to meet the popuse of the natural uneven-aged forest management.3)The relationship between the different tree diameters class and the growth per unit area in different tree species is a unimodal curve whice first increase and then decrease.Where the unimodal curve of the highest point on each are not idential.Cloud fir appeared a peak of the largest diameter class,which is 46 and 44 size level respectively,and then the Korean pine is 40, basswood is 36, birch is 28.This method determines the largest unit area of the accumulation of years of growth in different diameters class of the natural uneven-aged forest,reveals the growth and decline process of the trees.By this method,we can determine the mature of a single tree,and provide guidance for uneven-aged forest management.