Development And Application Of Density Management Diagram Of Pinus Tabulaeformis Carr.Multi-functional Plantation

In order to use practical management methods to manage Pinus tabulaeformis Carr.plantation,efficient utilization of forest resources,to play the economic and ecological benefits of Pinus tabulaeformis Carr.plantation.This study took Pinus tabulaeformis Carr.plantation in Yixian County as the research object,based on the collected forest resource inventory small class and sample plot survey data,through data processing and model fitting,constructed the Pinus tabulaeformis Carr.plantation stock density control map,and further developed the water conservation,carbon storage and biomass density control map.The multi-function density control chart was transformed from a single storage to carbon fixation and water conservation,and different site index curve models were established to connect stand age and density control chart,and the multi-function density control chart was applied.The main conclusions are as follows:(1)Based on the analytical tree data and the second-class survey data,the tree height DBH growth of Pinus tabulaeformis Carr.plantation was analyzed.Five empirical growth models including Logistic model,Richards model,single-molecular model,Gompertz model and Korf model were selected for fitting.It was found that the Richards model was selected as the optimal model for tree height.The DBH of the tree was selected,but the analysis model was the optimal model.The DBH of the tree height was positively correlated with the age.With the increase of age,the DBH of the tree height gradually increased.The status index curve constructed on this basis reflected that there were a great difference between tree height and age under different site conditions.The higher the status index is,the higher the tree height is.(2)Through the second-class survey class,the nonlinear regression analysis was used to fit the iso-tree height line model and iso-diameter line model,etc.,and the software Origin2017 was used to draw the curve group and form the storage density control chart.The average diameter of thinning stand was larger than that of non-thinning stand,and the stock volume of thinning stand was 2.8 m3/hm2 less than that of thinning stand once,and 25.3 m3/hm2 more than that of thinning stand four times,when the stand site condition was I grade and the initial density was 5 000 plant/hm2.In terms of density,the densities of thinning stands were all realized to reasonable densities,while the densities of non-thinning stands basically reached the maximum value.In terms of the growth rate of stock volume,the growth rate of thinning stands was higher than that of non-thinning stands.From the analysis of economic benefits after tree cutting,the wood income of thinning stands was higher than that of no thinning stands,and the economic income of thinning stands was the highest for two times.(3)According to the quantitative relationship between biomass carbon storage and storage,the density control chart of biomass and carbon storage was compiled.It was found that the biomass of the stands with Ⅲ level and an initial density of 2 000 plant/hm2 increased year by year when the stand age was 10～40 years,and decreased gradually when the stand age was 30～50 years.In terms of the target management design of carbon storage,when the stand site,initial density and average diameter are determined,th e carbon storage should be greater than 90 t/hm2 if the diameter is greater than 90 cm,so as to meet the operational requirements.After the appropriate age of thinning,when the average diameter of the stand grew to 21 cm,the carbon storage of the stand was 92.93 t/hm2,which reached the requirements of our business objectives.(4)In this study,the maximum litter water holding capacity was used to reflect the water conservation capacity of a stand.According to the relationship between the maximum litter water holding capacity and stand storage capacity,the following formula was obtained:Y=16.619 × In M-50.676.Calculate each curve model according to the accumulation density control chart,and compile the water conservation density control chart.When the initial density of the stand was 2 000 plant/hm2 and the average diameter was 10 cm,the maximum litter holding capacity of the stand without thinning after 30 a year was 57.8 t/hm2.The maximum litter holding capacity of the stand without thinning was 1 time after thinning and 2 times after thinning was the minimum.However,there was no significant difference in the maximum litter holding capacity between the stand with only one thinning and the stand with no thinning.However,the stand with only one thinning had a thinning density of only 0.87.while the stand with no thinning had a thinning density close to 1.Therefore,the maximum litter holding capacity of the stand with only one thinning had a large room for improvement.