Research On Carbon Sink Capacity Of Urban Forest Based On 3S Technology

Urban forest is an important part of urban ecosystem and the core of eco city construction.It is also the most important carbon sink base.It is of great significance to build a comfortable and livable ecological environment and maintain the balance of urban ecosystem.As the "city green lung and city purifier" of Jinan City,the southern mountainous area is the key link in the construction of Jinan city ecological green space system.Giving full play to the ecological effect of the southern mountainous area is of great significance for accelerating the process of urban ecology and promoting the sustainable development of urban-rural integration in Jinan.This paper takes the southern mountain area of Jinan as the research object,with 3S software as the main technical support,and the high-resolution satellite remote sensing images of the southern mountain area of Jinan in 2000,2010 and 2019 as the main data source(Landsat 8 satellite remote sensing image)for analysis and research.After the image is processed by geometric correction and image registration,the patch type distribution map of each land use is obtained.Through the collection of relevant literature,this paper selects the most suitable calculation model to quantitatively analyze the carbon sequestration and oxygen release and oxygen consumption in the southern mountainous area of Jinan City,and then obtains the carbon and oxygen balance value of the southern mountainous area by using the carbon and oxygen balance formula,and puts forward the Countermeasures to improve the carbon sink capacity of urban forests in the southern mountainous area of Jinan City.The research contents are as follows:1.Data processing of land use classification information in southern mountain area of Jinan CityThrough the processing of graphic data and attribute data related to land use classification,the southern mountainous area is divided into six categories: woodland,sparse woodland,cultivated land,wetland,construction land and unused land.Four categories are mainly used in the study: woodland,sparse woodland,cultivated land and wetland.From the data of the land use maps and tables interpreted in the three years,it can be concluded that: the land area of woodland shows a continuous growth trend in the past 20 years,with the growth rate of 1.06 from 2000 to 2010 and 1.02 from 2010 to 2019;the sparse woodland gradually decreases,with the decrease rate of 1.122 from 2000 to 2010 and 1.05 from 2010 to 2019;the cultivated land area shows a decreasing trend,with the decrease rate from 2000 to 2010.In terms of wetland,it increased by 9.72 hm² from 2000 to 2010 and 5.67hm² from 2010 to 2019.2.Calculation of carbon sequestration and oxygen release in southern mountain areaAccording to the biomass model method and the calculation formula,the carbon sequestration in 2000,2010 and 2019 in the southern mountainous area is 1172700 T,1188700 T and 1195900 t respectively,and the oxygen release is 932600 T,945200 T and951000 t.From 2000 to 2019,the carbon sequestration and oxygen release of urban forests in southern mountainous areas showed a straight-line upward trend,among which the proportion of forest land was the highest,the carbon sequestration increased from 811600 t to 875700 T,and the oxygen release increased from 644600 t to 695500 t.Secondly,the proportion from large to small is sparse woodland,farmland and wetland.Due to the promotion of relevant policies,the area of woodland is increasing,resulting in a steady decline in carbon sequestration and oxygen release of sparse woodland and cultivated land in recent years.In the aspect of wetland,the proportion is less than 1%,and its carbon fixation and oxygen release show an increasing trend from 2000 to 2010,and gradually decrease from 2010 to 2019.3.Calculation of carbon release and oxygen consumption in southern mountain areaAccording to Jinan City Statistical Yearbook and relevant literature,combined with the calculation formula,the total CO₂ emission of urban forests in the southern mountainous area of Jinan City in 2000,2010 and 2019 were 18.867 million tons,60.697 million tons and69.1521 million tons respectively,and the total oxygen consumption was 10.4458 million tons,31.0103 million tons and 35.6059 million tons.Taking 2019 as an example,the analysis and comparison show that the proportion of carbon emission from raw coal combustion is the highest,followed by the carbon emission from fuel oil combustion,followed by diesel oil and gasoline,and the least is liquefied petroleum gas;the oxygen consumption of raw coal combustion is the first pollution source of the City,and the proportion of O₂ consumption reaches 74%,the proportion of oxygen consumption of fuel oil combustion as the second pollution source reaches 13.38%,and the proportion of diesel oil and gasoline as the second pollution source reaches 13.38% The oxygen consumption of lpg combustion decreased in turn.4.Analysis of carbon sequestration capacity of urban forest in southern mountain area of Jinan CityThe results show that the carbon balance coefficients in 2000,2010 and 2019 are 0.86,2.55 and 2.89 respectively,and the oxygen balance coefficients are 0.56,1.64 and 1.87 respectively,showing an upward trend,and the most obvious in 2000-2010.Take 2019 as an example,that is,the total energy consumption of CO₂ released in southern mountainous areas in 2019 is 2.89 times of the absorbed amount,and the annual consumption of O₂ is 1.87 times of the fresh O₂ provided by the existing urban ecosystem.If the natural ecosystem in the southern mountainous area of Jinan needs to absorb the total amount of carbon released by the area average method,it needs to supplement78619.13hm² of forest land;if it needs to fill the oxygen consumption,it needs to supplement50871.2hm² of forest land;if it needs to supplement sparse forest land,cultivated land and wetland,it needs more area.5.Countermeasures for improving carbon sequestration capacity of urban forest in southern mountainous area of Jinan CityAccording to the problems of carbon sequestration in the southern mountain area,combined with the relevant research theory and guiding ideology,this paper puts forward the specific measures of efficient green space optimization strategy in the southern mountain area of Jinan City,and puts forward the specific implementation schemes of tree species optimization,water optimization and residents' lifestyle optimization according to the current situation,so as to achieve the purpose of improving the carbon sequestration capacity of urban forest in the southern mountain area of Jinan City.