Estimation Of Ecological Service Value Of Coastal Shelterbelt In Huancui District Of Weihai City And Influence Factors Analysis

Huancui District of Weihai City is a typical area for coastal protection forest construction in low mountain and hilly areas in Shandong Province.In order to serve the coastal shelterbelt project construction in the hilly area of Shandong Province,and to evaluate the construction effect of sea shelterbelt.In this study,seven typical forest stands were selected to estimate the quality and value of four kinds of ecological service value per unit area for water conservation,soil conservation,carbon fixation and oxygen release,and forest nutrient fixation.Sensitivity analysis was used to explore the sensitivity of total ecological service value to the change of different ecological service value per unit area,and stepwise regression analysis and path analysis are used to screen out the forest structure factors and soil physical and chemical properties that are important for ecological service value,which is the coastal defense of the study area.Forest construction puts forward reasonable forest management suggestions.The main findings are as follows:(1)Estimation of ecological service value:The total ecological service value of diff erent forest stands is in descending order of forest age:20a Robinia pseudoacacia pure forest(143203.1 yuan/t/(hm~2·a))>20a Pinus densiflora pure forest(93202.0 yuan/t/(hm~2·a)),5a Quercus acutissima+Cotinus coggygria mixed forest(55848.9 yuan/t/(hm~2·a))))>5a Pinus thunbergii+Quercus acutissima+Cotinus coggygria mixed forest(50375.9 yuan/t/(hm~2·a))>5a Pinus thunbergii+Quercus acutissima mixed forest(50374.5 yuan/t/(hm~2·a))>5a Pinus thunbergii+Quercus acutissima+Robinia pseudoacacia mixed f orest(48526.4 yuan/t/(hm~2·a))>5a Pinus thunbergia pure forest(23291.9 yuan/t/(hm~2·a)).The value per unit area of different ecological functions is sorted from large to small:Tree nutrient retention(144973.9yuan/t/(hm~2·a))>Conserve water(137065.6yuan/t/(hm~2·a))>Soil fixation and fertilizer preservation(111104.2yuan/t/(hm~2·a))>Carbon fixation and oxy gen release(71679.01yuan/t/(hm~2·a)).Older forest stands have relatively higher ecological service value,the ecological service value of the 20-year forest stand is better than that of the 5-year forest stand.20a Robinia pseudoacacia pure forest is better than 20a Pinus densiflora pure forest.In the same forest age,the ecological service value of mixed forest is higher than tha t of pure forest.(2)Sensitivity analysis:When the ecological service value factors of each function f luctuate by 10%and 20%respectively,Sensitivity to the ecological service value of co astal protection forests in the low mountain and hilly area of Shandong Province,in d escending order:Tree nutrient retention(±6.24%,±3.12%)>Conserve water(±5.9%,±2.95%)>Oxygen release function(±4.17%,±2.09%)>Fertility retention function(±2.25%,±1.13%)>Soil fixation function(±0.83%,±0.42%)>Carbon fixation function(±0.61%,±0.30%).The most sensitive factor affecting the total ecological service value of the study area is the nutrient retention function of the forest,and the weakest factor is the carbon r etention function.(3)Research on the relationship between stand structure factors and ecological serv ice value:Among the stand structure factors,the coverage and the thickness of the soil layer are the main factors affecting the function of water conservation;Soil thickness and diameter at breast height are the main factors affecting the function of carbon fix ation and oxygen release;Diameter at breast height is the main factor affecting the con servation of soil and forest nutrient retention.(4)Research on the relationship between soil physical and chemical properties and ecological service value:Among the factors of soil physical and chemical properties,total porosity,soil bulk density,soil organic matter and total phosphorus content are the main factors affecting the function of water conservation;Soil nutrient total nitr ogen and total potassium content are the main factors affecting soil conservation;Soi l bulk density is the main factor affecting carbon fixation,oxygen release and forest nutrient fixation.