The Study Of Larger And Middle-diameter Timber Of Cunninghamia Lanceolata Planted Forest's Optimum Harvesting Technology

The key to the accurate improvement of forest quality lies in the optimization of plantation harvesting techniques.Cunninghamia lanceolata in the central production area of Cunninghamia lanceolata in Fujian province had been regarded as the research object,685 fixed plots and temporary plot forestry survey data had been investigated and collected?93 strains of Cunninghamia lanceolata analysis data had been measured.The timber yield and maturity of Cunninghamia lanceolata plantation had been calculated by using the prediction model of stand growth and harvest,the slope equation and the diameter structure model.Theoptimalmanagementmodelforcultivatinglargeand medium-diameter timber of Cunninghamia lanceolata plantation had been obtained by using dynamic programming to determine the initial,interval and thinning volume of thinning for different cultivation objectives.1.The forest stand model had been established as the core,the model of polymorphic position index curve,the average high growth model of stand,and the full forest stand model of accumulation growth model had been established to realize the dynamic estimation of stand growth.The genetic algorithm was used to fit the growth prediction model of Cunninghamia lanceolata plantation in Fujian Province,which is closer to the production practice.After optimization,it can update and dynamically predict the production of Cunninghamia lanceolata forest resources in the Cunninghamia lanceolata.2.Based on the prediction model of growth and harvest of Cunninghamia lanceolata plantation,the number of mature ages of its plantation had been calculated by three initial planting densities and three status indices,and the mature age of Cunninghamia lanceolata plantation was 18~22 years.Based on the establishment of the sharpness equation and the analysis of the distribution of the diameter structure of Cunninghamia lanceolata plantation,combined with the prediction technique of Cunninghamia lanceolata growth and the standard of Cunninghamia lanceolata,the table of the yield of Cunninghamia lanceolata was calculated,and the growth of the target material was the largest.According to the standard,the mature age of Cunninghamia lanceolata plantation is calculated.According to the analysis,the small diameter material is 22 years,the medium diameter material is 26 years,and the large diameter material is 36 years.Based on the 6%discount rate,the status index is 16 hours,the mature age of Cunninghamia lanceolata is 15 years;the status index is 18 hours,the mature age of Cunninghamia lanceolata is 15 years;the status index is 20 hours,the mature age of Cunninghamia lanceolata is 15 years.3.The initial thinning interval,interval and thinning intensity were the three main considerations for the thinning techniques of Cunninghamia lanceolata plantation.The analysis of thinning techniques had shown that the initial period of thinning of Cunninghamia lanceolata plantation was about 8~10 years,the interval was 7~9 years,and the thinning intensity was 16~30%.It had been recommended that the management of Cunninghamia lanceolata plantation:the initial planting of 3000~4000 plants/hm~2 of forest stand,the forest land with a status index of 16 should be the target of breeding medium-sized timber,and the maximum income can be obtained through twice thinning.The status index is 18 and 20.In the woodland,the large-diameter timber had been cultivated as the target of afforestation,and the three thinning were required to obtain the maximum benefit.