| The forestry project invested by World Bank loan have been implementing for many years in Anhui Province. Most of them have been entering the young forest and closing crown stage at present. It is necessary to thin for them. Therefore, Forestry Deprtrment of Anhui Province promptly started "World Bank loan forestry sustainable development project～artificial forest thinning in Anhui Province ".The project's primary mission of the project is to complete the thinning of plantations which are invested by the World Bank. In order to get thinning to be more standard and science, it was started by Anhui Province forestry department that the research project on the World Bank loan forest thinning techniques. Its goal lies in the solution of the key technical question of thinning, for example thinning object and intensity decided and so on. World Bank project main afforestation tree species(Chinese fir, Masson pine, Slash pine) were used as the research object in this paper. The research on the site quality appraisal and density management table were developed for the three tree species so that they will provide the bases for the thinning of artificial forest.The research base were located at Huangshan, Xuancheng, Anqing, Chizhou cities. Three hundred and thirty temporary standard plots were established and investigated. The number of temporary sign of the plot for Chinese fir, Masson pine and Slash pine are 90,90 and 150 respectively.The sign of the plot is 0.067 hectare, and its shape is a rectangle. The 2055 dominating tree-height data were investigated. The crown and breast diameter materials of 18658 sample trees were collected from temporary standard plots.Richard, Logistic formulation and so on were taken for the dominating height growth models of the three trees species. The parameter, the residual mean square error and the correlation index of three models were calculated by Marquardt regression analysis means. One of three models was selected as the dominating height growth model according to the principles that the residual error is the smallest and the correlation index is the biggest. The results of model selecting are as follows: H=73.5932 (1-exp(-0.00179A))0.49834 for Chinese fir H=12.6343(1-exp(-0.123247A))2.7701 for Masson pine H=60.2529(1-exp(-0.010804A)) 0.917984 for Slash pineThe standard age and the interval of site index class is 20 years and 2m for Chinese fir Masson pine and Slash pine. The homograph site index tables for Chinese fir,Masson pine and Slash pine plantation were compiled by proportion means based on the guide curve. It is convenient for the site index table to use,so it becomes the commonly method to assess site quality. Compiling of the site index table can raise the forest management level and have an important significance.D=a+bd was taken for the model between the tree crowns diameter and Diameter at breast height. The result respectively is: Chinese fir:D=0.78184+0.14053d Masson pine:D=0.40554+0.22882d Slash pine:D=0.70872+0.15803dAccording to formula: Stheory =π·D2/4,ftheory =10000/Stheory,the stand mean theory crown and density were calculated based on the different stand mean diameter at breast height. The thinning intensity was put forward based on the difference between actual stand density and theory density. |
PDF Full Text Request