Study On The Management Mode Of Spruce-fir Mixed Coniferous Forest On Over-cutting Forest Region Of Changbai Mountain

The structure of over-cutting forest region on Changbai Mountain is destroyed gradually and the functions are degenerated due to human impacts and poor management, etc. Hence, structure adjustment, forest function recovery and reasonable management technique recommendation are required. This study focuses on the spruce-fir mixed coniferous forest amid over-cutting forest in Jingouling Forest Farm governed by Wangqing Forestry Bureau of Jilin Province whose ratios, determines the leading function, management objectives and goal structure and conducts structure adjustment to the forest and then weighs in with the management mode of spruce-fir mixed coniferous forest based on the analysis of its tree species composition, diameter and space structure characteristics. This provides the basis for recovering and perfecting the structure of spruce-fir mixed coniferous forest and for improving its management level and overall benefits. The main conclusions are:1. Develop a knowledge on the tree species composition, diameter and space structures of the object of study.The major tree species composition of the object of study includes fir, spruce and Korean pine. In addition, broad-leaved birch, maple, bass, poplar and elm and the like mixes together to constitute spruce-fir mixed coniferous forest. Stand forest of coniferous trees to broad-leaved trees are 9:1,8:2 and 7:3.The diameter grade and number distribution is expressed in a reverse letter "J" and the number decreases with the increase of diameter grade. The linearization technique of nonlinear function is applied to enable the reverse letter "J" curve of diameter distribution of the traditional natural forest to be converted to straight line and to make the correlation coefficient fall between 0.91 and 0.99.The distribution patterns of the object of coniferous trees to broad-leaved trees are 9:1 random distribution,8:2 aggregated distributions and 7:3 uniform distribution; from the perspective of ratios, the forest growth is under middlebrow state; in terms of mingling degree, the 7:3 is intensely mingled and the spruce-fir mixed coniferous forest at other proportions is moderately mingled.2. The management objective of the object of study is determined as ecological benefit and keeping one eye on developing timber forest.3. The goal structure is defined on the basis of comprehensive analysis of such indices as stand value q distribution, stable value, crown size, volume increment and regeneration characteristics and structure adjustment is conducted to the real forest.4. The management mode of spruce-fir mixed coniferous forest is brought forth. The management mode includs management principles, management aim, objective structure, and management technology system of structural adjustment etc. To offer theoretical foundation and technical support for the management of spruce-fir mixed coniferous forest in the over-logged forest region of Changbai Mountain. Objective structure is mostly determained by tree species composition, diameter sturcture and space structures.Tree species composition:The ratios of coniferous trees to broad-leaved trees applicable to the management objective are 8:2 and 7:3. The tree species composition is fir 30%-40%, spruce 20%, Korean pine 20% and broad-leaved trees 20%-30%.Diameter sturcture:Linear function of diameter grade and number are:y=--aχ+b.The linear expression of diameter structure of natural forest is more intuitionistic than the traditional reverse "J" curve and is convenient for application in real management. The adjustment of its parameter values can play an immediate role in adjusting stand structure, designing selective cutting intensity and estimating the diameter structures before and after felling. This shows that this parameter is readily operable in the design process of selective cutting and thus provides basis for the natural forest management, especially selective cutting.space structures:For space structure, angle index is adjusted to random distribution; for the ratio, middlebrow class is adjusted to the highest proportion and forest at inferior class is adjusted to the lowest; the mingling degree would better be adjusted to the frequency that extreme intensity and intensity mingling.