| Forest resources are the environmental basis for sustainable development and the material basis for human survival.Understanding and mastering the current situation and dynamic changes of forest resources can effectively carry out management of forest resources and achieve the goal of sustainable development of forest resources.The stand structure plays an important role in multi-objective functions such as wood production,ecological benefit,forest structure and function,etc.A reasonable stand structure is an important content to establish the forest resource system with the best overall function and give full play to the forest ecosystem.However,some plantations had poor stand quality and low ecological benefit.The age structure of stands is unreasonable;Pure forest increased,causing serious damage of pests and diseases.In the planning and design adjustment of forest resources,it is particularly important to study the rationalization of forest structure distribution and the choice of management mode,which determines the stand quality and future harvest of forest resources.Within this article yellow plantation as the research object,advantage of forest tree species in 2009 and 2018,the forest resource continuous investigation data and survey data as the foundation,USES mathematical statistics and comparative analysis methods to analyze the forest resources in the area of accumulation,reforestation,health status,the structure of the tree species and forest age structure of the status quo and dynamic change,find out the change of forest resource advantages and restricting factors.A forest harvest adjustment model was established by using multi-objective programming method from aspects of timber harvest,stand renewal and final stock volume,so as to provide an optimization method for the structural adjustment of forest resources.Two indexes,Euclidian distance and balance rate,were used to evaluate the optimization results.According to the seven indicators of productivity,organizational structure and resistance and the survey results of sample sites,combined with the analytic hierarchy process(AHP),the index weight was given to determine the index threshold,and the health evaluation index system was constructed.The composite structural function index method was used to evaluate and analyze the health of dominant tree species plantation.Combined with the management purpose and health status evaluation structure of the forest farm,four different management modes of industrial raw material forest,general timber forest,windbreak and sand fixation forest and undergrowth compound management in short rotation period were constructed,which provided the basis for the sustainable management of the plantation forest in neihuang forest farm.The main research results are as follows:1.In terms of tree species structure,the dominant tree species in Neihuang plantation were poplar(Populus)and Robinia pseudoacacia(Robinia pseudoacacia).Poplar accounted for 80.9%and Robinia pseudoacacia accounted for 19.1%of the tree species area,with single tree species structure.The area ratio of poplar to Robinia pseudoacinia in young forest,middle forest,near mature forest,mature forest and overmature forest was 64:7:4:22:3 and 0:0:4:16:80,respectively.The structure of age group was unbalanced and needed to optimize the structure of tree species.In terms of forest structure,the total area of timber stands is 1318.75hm~2,accounting for 57%of the operating area.The proportion of forest species such as ecological public welfare forest and shelter forest should be increased.2.By analyzing the dynamics of the area and stock of dominant tree species in the Yellow Forest Farm during the 10 years from 2009,it was found that the area of poplar decreased by 5.2%,and the stock increased by 14.2%;The area of Robinia pseudoacacia decreased by 47.7%,the stock decreased by 13.5%,the area of poplar and Robinia pseudoacacia decreased to develop diversified management,but the age group and age class structure of poplar and Robinia pseudoacacia was still unreasonable,such as the area proportion of young poplar forest increased by 23%,and the area proportion of middle age forest decreased by 39%;Robinia pseudoacacia overripe forest accounted for more than 75%.3,compared with an average annual growth rate in 2009 increased by 67.2m~3/hm~2,and volume of tree species and growth in 2018 than in 2009,and the improvement of forest management is a major cause of tree volume and growth,but the advantage species poplar and black locust resources of the overall quality is not high,should adjust measures to local conditions to strengthen the cradle,the cultivation of high quality trees.4,according to the sample survey,using the method of clustering analysis and composite structure function index,analyzes the advantages of health,which the artificial forest of poplar sapling forest,mid-maturation forest healthy,nearly cooked Lin is in a state of sub-health,the overall health,the health level of poplar plantation is higher,acacia plantations have a relatively low level of overall health;The number of healthy,sub-healthy and unhealthy small classes were 55,40,26,and the area was 307.8,373.53,456.85hm~2,respectively.The area ratio was 27.05:32.81:40.14,and there were 146 small classes in total.The management of mature and overmature forests should be strengthened to improve the health of stands.5.At the end of adjustment period,the area ratio of each age class of poplar was adjusted from 26:38:7:4:21:1:3:0 to 15:16:18:18:15,and the area ratio of each age class of Robinia pseudoacacia was adjusted from 0:0:0:4:0:16:14:66 to 28:27:23:23,and the stand age class structure was optimized.After the adjustment period,the quantitative index of forest resource structure changed greatly,and the balance rate of age class structure of two tree species reached 0.96.The European distance was reduced by more than 85%,and the locust was reduced by 100%.6.Four business models were constructed.The objective of the short-rotation industrial raw material forest model was to harvest a large number of high-quality timber in a short period of time,mainly planting poplars and carrying out intensive management;The goal of general timber forest model is to form multi-layer and multi-age mixed permanent storage forest and adopt the measures of near natural cultivation technology system.The goal of windbreak and sand fixation model is to stabilize the soil structure of forest farm and protect the surrounding natural ecological environment.The goal of the undergrowth compound management model is to diversify the products,give full play to the productive potential of land resources effectively,and protect the ecological environment on which agricultural production depends while increasing land income. |
