在数据收集、文献查阅及实地调查的基础上,采用市场价值法计算江苏省公路绿化的直接经济效益;采用当量法及 LY / T 721—2008 评估法分别计算在涵养水源、保育土壤和维持生物多样性方面以及在固碳释氧和净化空气方面的生态经济效益;采用替代市场价值法和当量法分别计算社会经济效益所包括的减少交通设施投入和景观美学价值,并据此对 2000 年至 2010 年江苏省公路绿化综合效益以及 2000 年至 2002 年的投资收益率进行了评估和分析。 结果表明:江苏省公路绿化综合效益从 2000 年的 3. 25 ×108元增加到 2010 年的 9. 40 ×108元,年均增长10% 以上;其中,直接经济效益、生态经济效益和社会经济效益分别占总效益的约 20% 、76% 和 3% ~ 5% ,生态经济效益的比例最高;在 2010 年的生态经济效益中按价值量由高至低各指标依次排序为固碳释氧(60. 00% )、净化空气(22. 80% )、维持生物多样性(6. 15% )、涵养水源(5. 59% )、保育土壤(5. 45% )。 此外,公路绿化作为森林碳汇,具有一定的固碳能力。 公路绿化产生的综合效益随绿化投入的增加而增加,其中,当年的直接经济效益(即木材价值)远小于当年的绿化投入,而当年的生态经济效益则高于其绿化投入,在综合效益中占主要地位。 总体上看,2000 年至 2002 年公路绿化的投资收益率都在 60% 以上。 研究结果表明:公路绿化乔木林的效益小于自然森林,但公路绿化的主要功能在于固碳释氧和净化空气,因而,应注重与完善公路绿化在净化空气方面的功能效益。 从长远的角度看,公路绿化是一项投资收益率较高的公益性基础设施项目。

Based on datum collection, literature consulting and field investigation, the direct economic benefit of highway greening in Jiangsu Province was calculated by market value method; the ecological economic benefit in water conservation, soil conservation and biodiversity maintaining and in carbon fixation and oxygen release and air purification were calculated by equivalent method and LY / T 1721—2008 evaluation method, respectively; the social economic benefit including traffic facility input reducing and landscape aesthetic value were calculated by substitute market value and equivalent methods, respectively. According to these calculation results, the comprehensive benefit of highway greening in Jiangsu Province from 2000 to 2010 and the rate of return on investment from 2000 to 2002 were evaluated and analyzed. The results show that the comprehensive benefit of highway greening in Jiangsu Province increases from 3. 25 × 10⁸ yuan in 2000 to 9. 40 × 10⁸ yuan in 2010 with an average annual increasing rate more than 10% . In which, direct, ecological and social economic benefits account for about 20% , 76% and 3% -5% of comprehensive benefit, respectively, and the proportion of ecological economic benefit is the highest. In accordance with index value quantity from big to small, the index order in ecological economic benefit in 2010 is carbon fixation and oxygen release ( 60. 00% ), airpurification ( 22. 80% ), biodiversity maintaining ( 6. 15% ), water conservation ( 5. 59% ), soil conservation ( 5. 45% ). Moreover, as one of carbon sink of forest, highway greening has a certain carbon sequestration capability. Comprehensive benefit produced by highway greening increases with increasing of greening investment, in which direct economic benefit, that is wood value, is much smaller than greening investment in the same year, but ecological economic benefit is higher than greeninginvestment in the same year and occupies the main position in comprehensive benefit. In general, the rate of return on investment from 2000 to 2002 is above 60% . It is suggested that arbor forest benefit of highway greening is less than that of natural forest, but the main function of highway greening is carbon fixation and oxygen release and air purification. Therefore, the benefit of air purification function of highway greening should be paid attention and improved. Highway greening is a public welfare infrastructure project with higher rate of return on investment in the long run.