【作者】 陈小红；

【导师】 张健；

【作者基本信息】 四川农业大学 ， 森林培育， 2008， 博士

【摘要】 退耕还林工程自1999年开始试点示范以来,工程总体进展顺利,成效显著。随着工程建设的继续推进,如何科学合理地反映退耕还林的效益动态,已成为政府部门、学术界和社会普遍关注的问题,也是退耕还林工程建设迫切需要解决的现实问题。本研究从还林模式和县域两个尺度对退耕还林效益进行了动态分析和综合评价,揭示了退耕还林综合效益的变化规律和发展趋势,为科学评价退耕还林建设成效和第二期工程建设提供了理论基础与技术支撑。以苦竹-扁穗牛鞭草、光皮桦-扁穗牛鞭草两种复合模式为研究对象,对其生态效益和经济效益动态进行了分析。随还林年限的延长,两种模式的总生物量、土壤入渗性、林地蓄水量、总孔隙度和O₂释放量逐渐增大,地表径流、泥沙流失量和土壤容重不断减少,苦竹-牛鞭草复合模式在林分郁闭后变化不明显;植被总固碳量和土壤有机碳和全氮量在林竹草复合期急剧下降,而后随着植被郁闭度的提高逐渐回升;苦竹-牛鞭草复合模式每年都可获得高于农耕地的经济收入,光皮桦-牛鞭草复合模式由经营利用周期较长,只有在林草复合期才能获得牧草收入。构建了退耕还林模式尺度的综合效益评价指标体系。该指标体系包括生态效益和经济效益2个项目层,水土保持、直接经济效益和间接经济效益等6个因素层,生物量、物种多样性和地表径流量等12个具体指标。运用模糊综合评价法和灰色系统模型对两种还林模式的综合效益进行了动态评价与预测。两种模式的系统稳定性、水土保持和固碳制氧等生态效益都在不断提高,苦竹林在林分郁闭后变化不明显;土壤改良效果目前不明显,但表现为恢复和提高趋势;苦竹林创造的经济效益高于光皮桦;随着还林年限的延长,两种复合模式的生态效益、经济效益和综合效益逐渐增大,整个生态经济系统正朝着良性循环方向发展;作为生态经济兼用林的苦竹,其综合效益高于光皮桦,且生态效益与经济效益耦合度高,值得在当地进行推广发展。分析了洪雅县退耕还林工程的生态、经济和社会效益变化。通过退耕还林工程的实施,洪雅县在生态环境改善、农村经济发展和社会生活方面发生了显著变化。到2007年为止,已累计增加林地生物量90.62万t,减少径流量0.36亿m³,蓄水量增加866.88万t,泥沙量减少37.3万t,固碳CO₂ 212.37万t,释放O₂116.24万t,还林地直接创造经济收入为6.96亿元。退耕还林工程对农业产值、畜牧业产值、农民人均收入、劳动力转移和农业产业结构等方面有着较大影响。构建了县域尺度退耕还林工程综合效益评价指标体系,包括3个项目层、7个因素层和12个具体指标,主要包括林草面积、林地蓄水量、泥沙流失减少量、林草直接收入、农民人均收入、畜产值和农村就业率等指标。对洪雅县退耕还林工程的综合效益进行了动态评价与预测。随着退耕还林工程的顺利进行,生态、经济、社会和综合效益整体上呈上升态势,现阶段综合效益主要体现在生态效益上,社会经济效益滞后于生态效益,但它们之间的协调耦合关系正朝着合理方向发展。提出了优化树种结构、优化调控还林模式、促进地方产业发展和提高劳动者素质等方面的退耕还林可持续发展对策。更多还原

【Abstract】 Some ecological,economic and social benefits were obtained since the Land Conversion Project（LCP）was tried in 1999.As the project construction is pushing forward, the problem that evaluation the dynamic benefit of the LCP scientifically and reasonably is not only concerned by government and public,but also needed to research and solve at present.This paper is studied on the forest（bamboo）-grass reafforestation patterns and Hongya County,the benefits of the patterns and the influenced aspect of the LCP were analyzed,the dynamic of the comprehensive benefit evaluation_index systems of pattern and county were established,the dynamic comprehensive benefits were evaluated and forecasted,and the dynamic law and trend were summarized,in order to provide the theoretical and technical approach for evaluation the achievement of the LCP scientifically.The dynamic of the ecological and economic benefits of the two reafforestation patterns（Pleioblastus amarus-Hemarthria compressa and Betula luminifera-H,compressa） were studied.Total biomass,soil infiltration,water conservation capacity,total porosity,O₂ release amounts of were gradually increased,surface runoff,sediment losses and soil bulk density were reduced,but the varieties for P.amarus-H,compressa pattern showed not evident during after the 4^threafforestation year;vegetation carbon stored contents,soil organic carbon and total nitrogen contents descended sharply when canopy was not closed,then increased gradually with the canopy density’s increasing.The previous pattern could attain higher incomes every year than farming land,but the later could obtain some economic incomes only from grass.Comprehensive benefit evaluation index systems of models were established that included 2 item layer such as ecological benefit and economic benefit,6 factor layer such as soil and water conservation,soil improvement,direct economic benefit and so on,and 12 indexes such as biomass,species diversity,surface runoff and so on,The pattern’s dynamic comprehensive benefits were evaluated and forecasted using fuzzy comprehensive evaluation method and grey systems theory,the results demonstrated that system stability,soil and water conversation capability,and carbon stored function and O₂ release amount were gradually increasing,whereas they didn’t change obviously after the fourth year for P.amarus-H,compressa pattern;the soil improvement effects didn’t show obvious,however they had restored and increased trends;whole ecological-economic systems were heading for favorable circulation when ecological benefit,economic benefit and comprehensive benefit gradually increased.In addition,P.amarus-H,compressa pattern could be popularized locally because of its higher comprehensive benefit.Ecological,economic and social dynamic benefits of Hongya County were studied during the LCP.After the LCP’s construction,Eco-environment was improved,rural economy was developed and social life quality was boosted.Until 2007,the total biomass was 90.62×10⁴t,sediment losses were 0.36×10⁸m³,water conservation content was 866.88×10⁴t,CO₂ stored contents were 212.37×10⁴t,and O₂ release amounts were 116.24×10⁴t,and direct incomes was 6.96×10⁸Yuan from the reafforestation land.In addition,the project promoted the increase of agricultural production value,livestock industry production value and farmer incomes,arranged the enough labors and improved agriculture industrial structure.Comprehensive benefit evaluation indexes systems of whole county were established that included 3 item layer and 7 factor layer and 12 index such as reafforestation area, water conversation content,sediment losses content,livestock industry production value and rural employment rate and so on.The dynamic comprehensive benefits of Hongya County were evaluated and forecasted.The ecological,economic,social and comprehensive benefit presented ascending situations,ecological benefits were playing role in the comprehensive benefits, and eco-social benefits were lagging behind,but the benefits and the relationship among different benefits would be increased and developed.Lastly,according to the previous analysis,sustainable development measurements of the LCP were put forward such as optimizing tree species structure,optimizing and controlling models,boosting local industrial development as well as improving labor quality and so on.更多还原