Forest Ecosystem Services Carbon Reserve Estimation Based On InVEST Model

Desertification Combating Program in the Vicinity of Beijing and Tianjin is one of the key ecological construction project of Beijing Municipal,which plays an important role in building Beijing a beautiful world city.As one of the important components of Desertification Combating Program in the Vicinity of Beijing and Tianjin,Huairou district practice an ecological conservation first in economic development of.In the study we selected the second phase of Desertification Combating Program in the Vicinity of Beijing and Tianjin in Huairou district as research area.By using the Integrated Valuation of Ecosystem Services and Trade-offs(InVEST model)and GIS software,one of the most important indicator of the ecological service functions of forest ecosystem-carbon stocks from 2014 to 2016 was estimated based on remote sensing images,soil and vegetation data.We also analyzed the carbon stocks differences among vegetation,soil,litter or among different engineering types and forest stands.Finally we estimated the carbon density and carbon stocks of forest ecosystems in Huairou area,making and the results visualized by form of images,so as to provide an effective basis for the local ecosystem protection and scientific management.Main results are as follows:(1)The total area of the project area from 2014 to 2016 is 2419.5 hm2,the total carbon stocks of forest ecosystem is 1725.83×102 t,and the carbon stocks has increased by 590.95×102 t;Among different types of forestry projects,the carbon stocks of forest ecosystems in low-efficiency forest reconstruction,Closing afforestation project,difficult site afforestation and suitable afforestation were 991.28×102 t,648.38×102 t,64.26×102 t and 21.92×102 t,respectively.The carbon density is the Closing afforestation project(77.84 t/hm2)>low-efficiency forest reconstruction project(73.30 t/hm2)>difficult site afforestation project(37.49 t/hm2)>suitable afforestation project(34.88 t/hm2).(2)Among the different forest types in the study area,the carbon stocks of deciduous broad-leaved forest was 798.31 x 102 t,the carbon stocks of shrubby forest was 769.47×10t,the carbon stocks of evergreen coniferous forest was 111.14×102t,the carbon stocks of coniferous mixed forest are 45.73 ×102 t,and the carbon stocks of deciduous coniferous forest was 1.18×102 t.The carbon density was coniferous and broad-leaved mixed forest(109.99 t/hm2)>evergreen coniferous forest(90.45 t/hm2)deciduous broad-leaved forest(76.46 t/hm2)deciduous coniferous forest(73.01 t/hm2)>shrub forest(63.63 t/hm2).(3)The carbon stocks of vegetation in the forest ecosystem of the project area was 458.35 × 102t,the carbon stocks of soil was 1194.19 ×102t,and the carbon stocks of litter was 73.29×102t,accounting for 26.6%,69.2%and 4.2%respectively of the total carbon stocks.The average carbon density was 71.33 t/hm2,which resulted from 66.70 t/hm2(2014),70.52 t/hm2(2015)and 73.44 t/hm2(2016),and 2014 to 2016 increased about 10.1%.Among them,the average carbon density of soil(49.36 t/hm2)>the average carbon density of vegetation(18.94 t/hm2)>the average carbon density of litter(3.03 t/hm2).(4)In 2014-2016,the proportion of arbor layer in the carbon stocks of vegetation layer in the study area was the largest,followed by shrub layer,while the proportion of herbaceous layer was the smallest.The carbon stocks of tree layer were 310.63 ×102 t,shrub layer 115.67 ×102t,and herb layer 32.05×102 t,accounting for 69%,24%and 7%of the total carbon stocks respectively.Among the carbon densities of vegetation,the carbon densities of tree layer,shrub layer and herb layer were 12.84,4.78 and 1.32 t/hm2.(5)In the soil carbon stocks in the research area from 2014 to 2016,the carbon stocks of 0-10 and 10-20 cm were relatively larger,which were 460.03×102 t and 343.70×102 t.The carbon stocks of 20-30 cm was 236.95×102 t,and the carbon stocks of 30-40 cm was 153.50 ×102 t.The average soil carbon density of 0-10,10-20,20-30 and 30-40 cm were 19.01,14.21,9.79 and 6.34 t/hm2,respectively.The In VEST model is feasible to assess the ecosystem service function of carbon stocks.Carbon stocks are affected by forest type,area and other factors,and the parameters can be corrected in the using process to improve the evaluation accuracy.The carbon density and carbon stocks in the three years showed an increasing trend,indicating that with the implementation of the second phase of the Beijing-Tianjin Sandstorm Source Control Project,the ecological service function of carbon stocks gradually improved.In the future implementation of the project,it is possible to increase the carbon density vegetation such as coniferous and broad-leaved mixed forests and evergreen deciduous forests to increase regional carbon stocks.