Study On Thinning Technology Of Building Artificial Mixed Forests For Multi-Storied Larch Plantation

The artificial Larix Olgensis was conducted six years ago by Thinning 2 keep 1(Type I) and Thinning 3 keep 2(Type II) respectively. To improve forest and tree structures, which can achieve the sustainable forest management in this article, utilized young forest and near-mature forest of artificial Larix Olgensis in Da Bian Gou forest farm were used. It studied different methods of striping thinning traces on reserved wood forest, diameter structure and regeneration of the basic growth, in order to update shade-tolerant saplings and cultivate new artificial multi-storied mixed forest. Compared with the effects of growth on different intensity strip thinned forest, this paper determined one type of the most efficient methods on artificial multi-storied forest to achieved optimal forest management. There were 4 results on the test land. The conclusions were are as follows:(1) Diameter distribution structure for artificial Larix olgensis after thinning was studied. The three-parameter Weibull function was utilized to simulate forest distribution of DBH growth. By using maximum likelihood estimation method and calculated by x 2, it proved that the three parameter Weibull function could describe the distribution of the diameter of the forest effectively. In addition, by thinning Weibull diameter distribution parameter values change could be understood the influence of diameter distribution structure by different strength strip thinning. It showed that the minimum diameter of strip thinning were larger than the unthinned forest in the young forest and half-mature forest. However, minimum diameter in near-mature forest and unthinned forest were almost the same. The level of increasing rate was type Ⅱ of forest, type I forest, and unthinned forest by order. As a result, the fastest type of the whole forest DBH growth rate was type II. At the same time, the strip thinning of young forest and middle-aged forest stand diameter distribution had the positive impact which could increase significantly the growth potential of the stand.(2) Different strength of implementing strip thinning on Larch plantation changed the density of forest and forest ecological environment by the way of building artificial multi-storied forest. To analysis the DBH, tree’s volume, volume of retain tree, after 6 years on young forest and half-maturate forest, the quantity of DBH and tree’s volume growth was: Type Ⅱ>Type Ⅰ>contrast group, the average DBH and volume growth significantly (p<0.05). Through this growth of near-mature had increased, the difference rete was little (P>0.05). On the other hand, the stand volume-was difficult to represent in this research in a short time as the less number of trees per unit area of forest to large extents.(3) The young trees after striping thinning in different types of Larch plantation and artificial regeneration in felling band. Different intensity strip thinning of the regeneration young trees,the average height, average diameter, average crown were all showed that:type II better than Type I of forest. Compared with 2011 saplings data, calculating four saplings, the average DBH growth quantity, tree height growth quantity and average crown diameter growth showed type II stand better than type I stand. It showed that the environmental factors of compound layer under mixed forest type construction was conducive to the growth of young trees.(4) The effects of different intensity strip thinning on Tree Mortality showed that:Young forest thinning Type I and type II forest mortality wood plants were 10.8% and 2.7% of the contrast group after 6 years; Half-mature forest thinning Type I and type II forest mortality wood plants were 18.2% and 54.4% of the contrast group after 6 years; Near-mature forest thinning Type I and type II forest mortality wood plants were almost the same of the contrast group after 6 years. As a result, it was obvious that thinning strip could reduce forest mortality compared with non-thinning strip.Due to all the research above, Type II was the most efficient method to cultivate new artificial multi-storied mixed forest. This type of strip thinning method could improve the artificial and productivity. It played an important role on the society, ecology. At the same time, it convinced that Type Ⅱ served the trend of Forestry Improvemence.