Study On Multi Function Density Control Chart Of Phoebe Bournei Plantation In Jindong Forest Farm

Close to nature forest management is an important management way to give full play to multi-function of forest.The best way to achieve close to nature management is target tree management.The key technology lies in the selection of target tree and the determination of target tree density at different stages of stand development,and the density control chart is the most direct and effective method to determine stand density.In this study,Phoebe bournei plantation in Jindong forest farm of Yongzhou City,Hunan Province was studied as the research object,Based on the data of fixed sample plots and temporary sample plots,the density control chart of Phoebe bournei plantation was prepared by using the density control chart model.The target tree density and stand density of the plantation were determined by using the density control chart.The stand carbon storage and maximum soil water holding capacity were obtained by using simultaneous equations Then the multi-functional density control chart is drawn to realize the transformation of the density control chart from single stand volume function to multi-function.The main research contents and conclusions are as follows:(1)Determination of target tree density of Phoebe bournei plantation in full cycle management.Based on the data of sample plots,the models of contour line,diameter line,maximum density line,density line and natural sparse line of Phoebe bournei plantation were constructed.According to the stand density control chart,the target tree density of Phoebe bournei plantation in three stages after the start of target tree selection were 360-720 trees/hm2 in quality selection stage,165-330 trees/hm2 in target tree growth stage and 65-130 trees/hm2 in stand volume growth stage.(2)Analysis of the mathematical relationship between multi-function factors and accumulation of Phoebe bournei plantation.Based on the carbon sequestration function and water conservation function,this study analyzed the multi-function of Phoebe bournei plantation,and found that the multi-function of the stand improved significantly with the extension of management time.From the carbon sequestration function of the stand,the carbon storage of Phoebe bournei plantation ranged from 13.92 to 47.36t/hm2,the carbon storage of the stand with the smallest stand density and the largest stand age was the highest,and that of the stand with the smallest stand age was the lowest The carbon storage is the lowest.From the perspective of water conservation function,with the increase of stand density,the maximum water holding capacity also increased,and began to decline after reaching a certain stand density.Regression analysis was used to analyze the relationship between multifunctional factors and stand volume,and the mathematical relationship between stand carbon storage,maximum water holding capacity and stand volume was obtained.The relationship is as follows:C=0.45 ×(0.4686×M+8.5182)(carbon storage,R2=0.9427),Y=504.21 ×ln(M)+985.16(maximum water holding capacity,R2=0.8657).(3)Research and construction of multifunctional density control chart of Phoebe bournei plantation.Based on the mathematical relationship between carbon storage,stand maximum water holding capacity and volume,the relevant mathematical models of carbon storage density control chart and water conservation density control chart were obtained.The carbon storage density control chart and water conservation density control chart were drawn by using origin 2018.The multi-function density control chart can predict and quantitatively investigate carbon storage and maximum water volume.It can accurately estimate the time when the stand reaches the saturation state,so as to carry out scientific and effective management measures on the stand in time,so as to ensure that the carbon storage and maximum water holding capacity of the stand are maintained in the best state.(4)Suggestions on management of Phoebe bournei plantation in Jindong Forest Farm.Through the stand density control chart and multi-functional density control chart of Phoebe bournei plantation,the target tree density and stand density of the whole cycle management of Phoebe bournei plantation in Jindong forest farm were determined.With productivity as the main goal,the stand density of Phoebe bournei plantation in each stage of stand development was 2500 plants/hm2 in the stage of stand establishment,1680 plants/hm2 in the stage of competitive growth,960 plants/hm2 in the stage of quality selection and 630 plants/hm2 in the stage of target tree growth;Based on the function of carbon fixation,the stand density of Phoebe bournei plantation in each stage of stand development was 2500 trees/hm2 in the stage of stand establishment,1580 trees/hm2 in the stage of competitive growth,920 trees/hm2 in the stage of quality selection and 580 trees/hm2 in the stage of target tree growth;Under the guidance of water conservation function,the.stand density of each development stage of Phoebe bournei plantation was 2500 plants/hm2 in the stage of forest establishment,1620 plants/hm2 in the stage of competitive growth,940 plants/hm2 in the stage of quality selection and 570 plants/hm2 in the stage of target tree growth.According to the different functional requirements of the stand,the reasonable selective cutting operation should be carried out to ensure the maximum productivity,carbon storage and water holding capacity of Phoebe bournei plantation.