中文摘要：

北京的生态安全始终是政府高度关注的问题。近年来,北京市政府不断加大对林业建设的公共投入,同时也吸引了众多社会资本以加强对林业的投入,有效提升了北京林业整体水平和森林生态系统的整体服务功能。为了提高林业投入产出效率,实现林业资源的有效配置和规模效益,本文选取林业固定资产投资完成额、林业系统年末从业人数、造林面积、林业产业结构比例、林业产业产值和林木绿化率6个投入产出指标,运用考虑规模收益的DEA模型（BC2-DEA模型）对1993—2013年北京林业的投入产出效率进行了测算,并对测算结果进行了分析。结果显示,1993—2013年,北京林业投入产出的综合效率总体上是比较高的,21年内的平均综合效率值为0.966。在总体综合效率变化上,1993年以来,林业投入产出效率较好,总体效率变化趋势大致平稳,小有波动。其中处于DEA有效状态的年份14年,另外有7个年份处于DEA无效状态。研究还对北京林业投入产出效率的主要影响因素进行了分析,指出林业固定资产投资完成额的变化对林业投入产出效率的影响最大,林业产业结构比例对目前北京林业投入产出效率的影响相对较小。另外,林业投资管理、生产管理等也影响林业生产效率。研究建议,今后北京的林业发展应主要集中在稳定固定资产投资、加大产业结构调整、提高林业的投资和生产管理水平上。研究对促进北京林业生态与经济的协调发展、提高林业投入产出效率及实现林业可持续发展等有重要意义。

英文摘要：

The ecological and environmental safety in the capital city is an issue always highly concerned by the government of China. In recent years,Beijing has greatly increased investment in forestry,and also attracted a wealthy of social funds to uplift the overall level of forestry and the forest ecosystem services.In order to improve the forestry input-output efficiency and to achieve the effective allocation of forestry resources and economies of scale,we selected six forestry input-output indexes,i. e.,forestry investment in fixed assets,number of employees at the end of the year in forestry sectors,planting area,proportion of forestry industrial structure,output value of forestry industry and the rate of woody plant cover,and used DEA model which considers the return and scale（ BC2-DEA model） to calculate the forestry inputoutput efficiency in Beijing from 1993 to 2013. The results show that the comprehensive efficiency of forestry input and output in Beijing is relatively high from 1993 to 2013. The average value of comprehensive efficiency is 0. 966 in 21 years. As for the change of comprehensive efficiency of forestry input and output,the condition of forestry input-output in Beijing is good since 1993,and its efficiency is generally stable with small fluctuations. In the 21 years,14 are in a state of DEA efficiency,and 7 in the state of DEA inefficiency. We also analyzed the main factors affecting the forestry input-output efficiencyin Beijing,and point out that the change of the forestry investment in fixed assets is presently the main factor while the proportion of forestry industrial structure has little impact. In addition,factors like forestry investment management and production management also have an impact on the production efficiency. We propose that forestry investment in fixed assets in Beijing should keep stability in the future development and the industrial structure for forestry should be adjusted. Furthermore,the level of forestry investment and production management should be raised gradu