Carbon Storage And Economic Value Assessment Of Urban Forest Vegetation——a Case Study Of Xuzhou City

Based on the data of Forest Management Inventory in2009, Biomass expansion factor and average biomass methods are used to estimate the total biomass, presenting the distribution trend of carbon storage and density of forest vegetation in Xuzhou. Through accounting the carbon emission of Xuzhou in2009, the rate of emission reduction and the economic value of forest carbon sink are revealed in this research. The results show that:(1) In2009, Xuzhou forest vegetation carbon storage is6.4515Tg, carbon storage of arbor forest is the highest, about5.4491Tg, respectively84.46%account for the total vegetation carbon storage. The result shows the arbor forest is the main contributor of vegetation carbon storage, But the carbon sequestration function of the shrub, odd tree and economic forest also can not be ignored.(2) The carbon storage of forest vegetation in Xuzhou increases0.5061Tg between2005and2009, with an average annual increase by0.1265Tg and an average annual growth rate of2.54%; The average density of forest vegetation carbon increases from25.85Mg·hm-2in2005to27.37Mg·hm-2in2009. This result suggests that, Xuzhou forest is "carbon sink" from2005to2009, and it will play a more and more important role of carbon sequestration in the future.(3) The arbor forest biomass and carbon storage of different counties’forest vegetation generally present a gradual increasing trend from city to suburb and to exurb in Xuzhou. But the carbon density decreases gradually from the city to the exurb. The uneven distribution of acreage and volume of dominant species is a common phenomenon, resulting in the difference distribution of carbon storage in Xuzhou. The sum of poplar and cypress carbon storage is5.3491Tg, accounts for98.16%of the total forest vegetation carbon storage in Xuzhou, showing the two dominant species have great contribution to the carbon storage of forest vegetation in Xuzhou.(4) The distribution rule of arbor forest carbon storage of forest vegetation in Xuzhou is: broad-leaved forest> coniferous forest> coniferous and broad-leaved mixed forest; and middle-age forest>per-matured forest> young growth forest> matured forest> over-mature forest; and high canopy density>middle canopy density>low canopy density. The distribution rule of arbor forest carbon density of forest vegetation in Xuzhou is:coniferous forest> coniferous and broad-leaved mixed forest> broad-leaved forest; and over-mature forest> matured forest> per-matured forest> middle-age forest> young growth forest; and middle canopy density> high canopy density> low canopy density.(5) In2009, the carbon emission including energy consumption, transportation, construction, farmland utilization, residents living and population breathing, amounts to46.521million t, per capita4.858t in Xuzhou, The forest vegetation absorbed0.464million t CO2, while the reduction accounted for1%by carbon emission. It showed the offset function of forest vegetation on the carbon emission plays a small role in Xuzhou.(6) In2009, the economic value of forest vegetation carbon sinks vary with the different unit price of carbon sequestration. And the broad-leaved forest has the mainly capacity of forest vegetation carbon sinks in Xuzhou. At present, the forest vegetation is mainly in young and middle-age growth forest in Xuzhou. Its carbon sinks function will play better over time, with greater economic benefit of carbon sequestration.