Study On Industrial Raw Material Forest Thinning Optimization

Thinning is the process of forest management, management measures are very important. Forest thinning is to develop a reasonable productivity, especially in plantations is an important technical measures.Through timely and reasonable manner thinning, tree growth can be accelerated to improve quality and increase the timber production forests, particularly in enhancing the forest site quality, species richness increased understory vegetation plays an important role.In this paper, industrial raw material forest and pine plantations of Cunninghamia lanceolata (Lamb.)Hook. plantation study, Focuses on Chinese fir plantation and thinning intensity on the growth impact of Pinus massoniana Lamb plantation, understory vegetation on the two identification methods in identification and classification of the application of thinning, the density control of a continuous state of planning, design based on three times in the thinning of the design of most Birth control and other aspects of research, To explore the survey data on forest resources to build an ideal thinning model for practical forest management provide the theoretical basis and application model. Concluded as follows:(1) Different thinning intensities on the growth of treesCunninghamia lanceolata (Lamb.)Hook..plantation thinning intensities were 0%, 20%, 30%, 37%, 62.5%, in DBH, tree height, crown width, tree volume, stand volume growth on the other, with the thinning intensity increased, the growth rate increased correspondingly, the performance of which the most sensitive factor is the diameter at breast height; Lin Under the diversity of herbaceous plants and the corresponding index value also increased with thinning intensity tended to increase, but the relative change in value is not obvious; the number of understory shrub species, average height, average diameter and total number of individuals are as thinning intensity increased, respectively from 0-15 species ,0~2.5 m ,0~1.8 cm ,0~87 showed an increasing trend to varying degrees.Pinus massoniana Lamb plantation thinning intensities were 0%, 10%, 23%, 38%, 65% in diameter at breast height, tree height, crown width, tree volume, stand volume growth on the other, with the thinning intensity increase the growth rate increased correspondingly, the performance of which the most sensitive factor is diameter at breast height; Understory herbaceous layer, Dicranopteris Dichotoma Bernh, which cover the more obvious Dicranopteris linearis, its cover with the thinning intensity increased, the increase is relatively significant, the other small species such as Miscanthus floridulu Warb, Gahnia tristis Nees, Woodwardia japonica such coverage did not change significantly; The number of shrub species, average height, average diameter and total number of individuals are as thinning intensity increased, respectively from 3-8 kinds of ,0.5~1.8 m ,1.3~2 .8 cm ,12~38 was significantly increased in varying degrees trend.(2) Industrial raw material forest thinning technique of making discriminationIn this paper, the discriminant analysis and projection pursuit method based on improved identification and classification of two methods, the establishment of forest thinning and thinning discriminant function classification were studied. In this paper, canopy density, stand dominant height, stand average diameter at breast height, average tree stand high four factors construct and discriminant discriminant function classification.This paper obtained the Cunninghamia lanceolata (Lamb.)Hook. plantation and the Pinus massoniana Lamb plantation thinning of the discriminant function are: Y杉=?0. 20070952X1 +0.07289315X2?0.15258011X3+0.00208150X4Y马=?0. 42506101X1 +0.00501726X2?0.00267213X3+0.00163249X4For a piece of unknown types of stand, stand by the field survey for more than four factors, and then into the discriminant function can be obtained on behalf of identification results. In this paper, the Cunninghamia lanceolata (Lamb.)Hook. plantation thinning determine the critical value; Pinus massoniana Lamb plantation thinning determine the critical value:.Critical value based on the size, the type of forest thinning is not unknown, just the corresponding data into the checking function, through comparative analysis with the critical value can be obtained by specific types of discrimination.Application of projection pursuit method to improve the discriminant results obtained: the projection of Cunninghamia lanceolata (Lamb.)Hook. lantations concentrated in the sample data (0.25 ~ 0.35) does not need thinning interval for the type; projection value concentrated in (0.4 ~ 0.6) The range of thinning types as needed; Pinus massoniana Lamb plantations are concentrated on the sample data projector (0.25 ~ 0.35) does not need thinning interval for the type; projection value concentrated in (0.4 ~ 0.6) Type of range for the urgent need for thinning. Types of forest thinning for the unknown, simply run into the corresponding data can be of specific types of discrimination.(3) Industrial raw material forest density control of continuous state dynamic programmingPinus massoniana Lamb plantations and Cunninghamia lanceolata (Lamb.)Hook.and density from the decision-making optimization results show that with increasing age of plantation forest species, the position of index less and less forest reserves Tree, Chinese fir plantation site index from 14m ~ 16m, pine plantation site index from 10m ~ 20m, the forest stand age of each tree as the reservation lines decreased with increasing site index.Show that the density control decision dynamic programming model in line with population growth pattern. Status index for different levels of Cunninghamia lanceolata (Lamb.)Hook. and Pinus massoniana Lamb plantation, to keep the same population Standing Tree, and the thinning interval should vary depending on site quality. High-status index level stands, thinning should be shorter intervals; low-status index level stands, thinning of the interval be longer.(4) Three design and design control plantation thinningThe actual production of Cunninghamia lanceolata (Lamb.)Hook.plantation forest management, the operation can be thinned during the 2 best, in which the first thinning time can be between 10~12 years, the second thinning time can be between 16~18 years, and cutting time in 25 years; Pinus massoniana Lamb plantation forest management in production and operation period is better, intermediate 2, the first thinning time can be between 10~12 years, the second thinning time can be between 16~18 years, and cutting time 24~25 years. This optimization for the plantation of Chinese fir and pine forest tending and practical results are consistent with management operations.