Study On Optimization And Adjustment Of Landscape Forest Structure Based On Target Tree Method

Stand structure is an important index to characterize stand characteristics,and plays an important role in forest function development.The adjustment and adjustment of stand structure will help to improve the accuracy of forest management decisions.The main purpose of scenic forest is to play the function of forest recreation,appreciation and convalescence,and the evaluation of landscape quality of landscape forest is the basis and prerequisite for the effective management and utilization of scenic forests.With the continuous improvement of the demand for forest landscape quality,it is an important part of the current forest management to combine the optimal adjustment of the landscape forest forest structure with the landscape quality evaluation and improve the efficient management of the Forest Park scenic forest.Taking the Forest Park of Jin Siwan,Sanming City,Fujian as the research object,the ecological vulnerability evaluation index system was constructed by AHP-entropy weight method.The ecological vulnerability of the study area was evaluated and analyzed.Based on the distribution of ecological vulnerability,two types of forest survey data and functional requirements were used to zoning the landscape recreation area,and 8 areas were set up in the landscape recreation area.Standard,from two aspects of the forest space structure and community landscape features,the landscape forest landscape quality evaluation model is constructed to determine the main factors affecting the beauty degree.Based on the constructed beauty evaluation model,the optimization strategy of scenic forest is determined,and the 110 Mu scenic forest in the study area is optimized by the target tree method;from the non spatial structure,space structure and forest landscape.The quality of scenic forest is evaluated and analyzed from three aspects of view quality.The main conclusions are as follows:(1)The vulnerability of Forest Park in Golden Bay is divided into five grades,which are micro,mild,moderate,moderate,intensity and extremely fragile.The area is 3.01km2,62.39km2,66.75km2,13.68km2 and 5.87km2 respectively.The area of moderate fragile area is the largest,followed by the intensity fragile area,and the index weight ranking of the ecological vulnerability in the study area is gradient(0.2649)>human interference(0.2614)>Slope direction(0.2430)>vegetation coverage(0.1197)>age group(0.0619)>canopy density(0.0491);the overall vulnerability index of the study area was 0.48,between mild fragile and moderate fragile areas,and the ecological environment was good.(2)The function area of Jin Siwan Forest Park is divided into three categories,including water conservation area,soil and water conservation area and landscape recreation area.The water conservation areas are mainly distributed in the northeast and southwest of the study area.The soil and water conservation areas are mainly distributed in the middle of the study area.The landscape recreation areas are mainly distributed in the northeast,northwest,southwest and south parts of the study area.The ecological vulnerability indices of each functional area are 0.46,0.49 and 0.55,respectively,and four functional areas are moderately fragile.Based on vulnerability analysis,we put forward strategies for business management.(3)Taking the scenic forest of the research area as the object,the value of the beauty of the photo is judged as the independent variable,and the score value of the main factors affecting the landscape is taken as the dependent variable,and the model is SBE=-0.048X1-0.085X5-0.151X70.112X9+0.067X11+0.147X19+0.216X22-3+0.212X23-1-0.159.The factors that affect the beauty of scenic forest are:litter>forest underlayer uniformity>tree richness>canopy density>DBH>competition index>competition index>lower branch height>angle scale;among them,the height,canopy,litter,and underlayer uniformity are positively correlated with the beauty degree,and the angle scale,competition index,tree richness and DBH variation coefficient are negatively correlated with the beauty degree.(4)According to the results of scenic forest beauty evaluation model,the optimal adjustment strategy of scenic forest was determined:to properly clean the litter of the forest and to improve the hygienic condition of the forest,to improve the hygienic condition of the stand,to switch the branch to the height of the branch,to adjust the density of the stand properly,to divide the stand into the middle and lower three layers,to improve the uniformity of the undergrowth of the forest,and to choose a few large chest paths.The forest tree is the target tree;the forest canopy density is reduced,the penetration degree is increased,the competition index is reduced,the competition between the trees is reduced by the selective cutting,and the tree species with morphological or color change are properly planted to increase the species diversity and improve the forest landscape quality according to the suitable tree,diversity and seasonal change principle.The criteria to determine the selection of the target tree:the landscape value is in grade Ⅰ～Ⅲ;the crown length>1/4 tree is high;the living power is high,there is no damage and disease and insect damage;it is in the upper layer of the stand,the size ratio U=0,the average crown diameter ratio less than the straight forest,and the angle in the 0.475～0.517.The selection of cutting wood is based on the determination of the target tree and the surrounding interference tree by using the Tyson polygon.Based on the competitive relationship between the target tree and the adjacent wood in the horizontal and vertical direction,the competition level is divided into 9 levels,and the first level indicates the most fierce competition,and the Ninth level indicates the minimum competition degree.According to the competition level,the forest with competition level of 1～4 is selected as cutting timber.(5)A total of 110 mu of scenic forest was optimized in the scenic forest of Forest Park in Jin silk Bay,and the optimized management effect of the landscape forest was analyzed and evaluated from three aspects of the non spatial structure,spatial structure and forest landscape quality of the forest.Selected felling species were mainly Castanopsis Castanopsis and Schima superba,and the structure of the community changed little after selective cutting,and the biodiversity index increased after selective cutting,and the stand adjustment was mainly concentrated in the middle diameter group and the large diameter group;the upper forest was reduced to the largest,21.83%of the original trees before and after the selective cutting,and the selective cutting was mainly concentrated in the upper layer of the forest.The average angle of the stand was reduced from 0.576 to 0.547,and 5.04%decreased.The average mixed degree of the stand changed from 0.471 to 0.479,the mixed degree increased by 1.67%,and more moderate mixed.The average size was changed from 0.500 to 0.496.The change around the mean state of the stand was not changed.The selection of the trees did not affect the overall distribution of the stand,and the stand still successional and developed in a healthy way.The beauty analysis before and after selective logging showed that the beauty value of the whole stand was increased from-0.499 to-0.046,with a increase of 90.788%.The target tree was cut down by the tree of the colorful branches and the trees without the value of cultivation,and the shade and color of the stand were adjusted to a certain extent,and the landscape aesthetic value of the whole stand was increased to a certain extent.