Study On Optimization Of Spatial Structure Of Cunninghamia Lanceolata Ecological Public Welfare Based On Multi-functional Management

The main function of ecological public-welfare forest is to meet the ecological need for the protection and improvement of human environment, ecological equilibrium, biodiversity and land security. In ecological niches important Cunninghamia lanceolata plantation is divided into ecological public welfare forest, Cunninghamia lanceolata ecological public welfare forest single structure, low biodiversity and productivity, a serious pest that Chinese Fir Ecological Forest multifunction inefficient. Therefore, improving the ecological public welfare forest benefits versatility has become an urgent issue of the current forestry workers need to be addressed. Structure determines function, reasonable adjustment stand structure, from the uniform angle, mingling degree and neighborhood comparison structure optimized to achieve multi-functional stand improving efficiency.This study takes the Cunninghamia lanceolata ecological public welfare forest as the research object in Fushou Forest Farm of Pingjiang county, Hunan province, using the spatial structure data of forest trees of 18sample plots in the young forest, half-mature forest and near mature forest, Construction of the multi-purpose water and soil conservation, species diversity, carbon sequestration, Productivity functions, the four features with a total of 18 indicators, established a multi-functional evaluation system, analyzed the structural characteristics of the stands, optimized the spatial structure of the stands, established the intermediate felling and replanting optimization. After four years of growth of stand optimization, analysis and evaluated the multifunction of Cunninghamia lanceolata ecological public welfare forest with different age groups, analysis the single-function and the overall function before and after the structural optimization of Cunninghamia lanceolata ecological public welfare forest, analysis the difference and variation. Research methods including GIS technology, Weibull distribution fitting, Delphi method, DBH weighted Voronoi diagram, species isolation level analysis, competitive analysis, stand spatial distribution pattern analysis, Delaunay triangulation, ANOVA analysis of variance, LSD (least significant difference counting method) multiple comparison. The main contents and conclusions are as follows:(1) Analysis the spatial structure of Cunninghamia lanceolata ecological public welfare forest. Analysed the DBH and tree height by Weibull distribution. The results shows:Diameter structure gradually increases with age group standard deviation change, young forests tend to trail order, more concentrated distribution, middle-aged forest, near mature forest trails bias in order, distribution is relatively discrete. Young forest does not meet the Weibull distribution curve,15 and 16 middle-aged forest plots 7 and 10 and nearly mature forest plots in line with Weibull distribution curve. Tree structure in turn increases with high standard deviation of changes in the age group, young forest saplings biased, centralized distribution, middle-aged forest, mature forest near biased high tree, centralized distribution, four young forest, and two middle-aged forest nearly two mature forest accord Weibull distribution function, stand diameter and tree height distribution unreasonable. From the spatial structure characteristics point of view, using the uniform angle, mingling degree and neighborhood comparison 3 of the uniform spatial structure analysis showed that the degree of isolation of stand space generally low, moderate competition state competition, spatial distribution pattern for the slug, Cunninghamia lanceolata ecological public welfare forest sub-space structure is irrational, it need for spatial structure optimization.(2) Analysis the multifunction of Cunninghamia lanceolata ecological public welfare forest. From water and soil conservation, species diversity, carbon sequestration and Productivity functions 4 multifunction indicators. The results shows: Water and soil conservation from the functional point of view, the soil water holding capacity nearly mature forest above the young forest and middle-aged forest, and there is a significant difference, soil porosity with increasing stand age after the first increase in a trend of decrease soil bulk density with increasing stand age showed an increasing trend. From the functional point of view of species diversity with increasing stand age showed an increasing trend, the highest species diversity near mature forest functions. Carbon sequestration from the stand point of view, the tree layer, shrub layer and litter carbon stocks with increasing stand age showed an increasing trend, herbaceous layer carbon stocks showed a decreasing trend, carbon storage in the soil layer increased first decreasing trend, productivity features and trends as carbon sequestration. Taken together, the Cunninghamia lanceolata ecological public welfare forest with different age groups multifunction generally low, not fully multifunctional benefits of Public Welfare.(3) The spatial structure optimization of Cunninghamia lanceolata ecological public welfare forest. Horizontal distribution patterns stand spatial structure, degree of isolation and species competition three aspects to adjust the direction of the uniform angle, mingling degree and neighborhood comparison of spatial structure constraints, the establishment of the Construction of Cunninghamia lanceolata ecological public welfare forest intermediate felling optimization program, Delaunay triangulation to represent a blank area around the trees, based on the position determination in replanting trees to build Delaunay triangulation in the largest triangular heart, and select local replanting native trees as objects, build Cunninghamia lanceolata ecological public welfare forest replanting program optimization. Improve forest species diversity, adjustment stand level distribution pattern, reducing competition forest, young forest replanting the panicled goldraintree and Chinese Tulip Tree, a middle-aged forest replanting Michelia maudiae, panicled goldraintree and Chinese Tulip Tree, nearly mature forest replanting the Taxus, realization of conifer and broadleaf mixed. After optimization, the spatial structure of Cunninghamia lanceolata ecological public welfare forest with different age groups have been optimized to reduce forest competition, stand level distribution pattern of rationalization, species diversity significantly.(4) Comparative Analysis the before and after multifunction of spatial structure in Cunninghamia lanceolata ecological public welfare forest. Optimized the spatial structure of stand forest, after four years of growth, analysis the multifunction of Cunninghamia lanceolata ecological public welfare forest with different age groups, and comparative analysis the former optimization multifunction of stand spatial structure. The results shows:management plots stand multifunction efficiency has been significantly improved without structural optimization multi-function control plot to enhance the effect is not significant, part of the function declined. Water and soil conservation from the functional point of view, management plots soil water holding capacity and soil porosity averages respectively improved 32.57% and 8.40%, control plot on soil water holding capacity upgrade 7.31%.soil porosity decreased 13.99%. Management plots plots of soil bulk density decreased by 19%, control plot bulk density of soil still fell 12.73%. From the functional point of view of species diversity, through Composite Index SDCI built the species diversity, management plots manner with respect to the average of SDCI front structure optimization and upgrading of 20.27%, SDCI mean to control plots be reduced by 26.64%, which is illustrated by the Cunninghamia lanceolata ecological public welfare forest to optimize the structure of space, to enhance the stand species diversity have a significant effect. From the functional point of view carbon sequestration, aboveground carbon sequestration enhance management plots 28.19 percent,15.55 percent of the control plots enhance, some management plots carbon sequestration underground enhance 15.05%,3.51% to enhance control plots sequestration capacity building for still higher than the ground. From the functional point of view of productivity, management plots r with respect to the productivity front structure optimization and upgrading 21.64 percent,16.16 percent of the control plots enhance, enhance experimental plots effect is remarkable.(5) Evaluating the multifunction Cunninghamia lanceolata ecological public welfare forest spatial structure sptimization of before and after. By building Cunninghamia lanceolata ecological public welfare forest evaluation system, evaluated the multifunction before and after the optimization of the spatial structure of Cunninghamia lanceolata ecological public welfare forest, the results shows:before the spatial structural optimization and multi-functional evaluation excellent good level and so no, moderate levels of 5, nearly mature forest there are 3, I’m young and middle-aged forest each 1, and poor in 13, accounting for 72.2%, young and middle-aged forest mostly forest. After good structural optimization and other plots to nine, including forest management plots of two young, middle-aged forest 3, nearly three mature forest, still on the ground near a mature forest, the total Chinese Fir Ecological Public Welfare 50% of the forest, poor sample reduced to three, accounting for 16.7% of the entire Cunninghamia lanceolata ecological public welfare forest. This shows that Cunninghamia lanceolata ecological public welfare forest with different age groups multifunctional benefits generally low, Cunninghamia lanceolata slow growth, irrational stand structure, stand by optimizing the spatial structure, regular Thinning and replanting native trees, multi-functional benefits of Cunninghamia lanceolata ecological public welfare has been Significantly increased.