【作者】 常胜；

【导师】 李江风；

【作者基本信息】 中国地质大学 ， 土地资源管理， 2010， 博士

【摘要】 土地作为人类生存与发展最重要的资源之一,是人类生存的载体,是人类一切生产和生活的场所。协调人地关系,可持续利用土地资源是经济、社会可持续发展的基础。土地可持续利用评价是土地可持续利用研究的关键问题,是土地可持续利用研究由理论到实践的必经环节,也是实施土地可持续利用的重要手段,是开展区域国土整治、土地利用规划和土地利用制度制定的重要依据。“结构决定功能”,土地空间镶嵌的稳定性是土地功能稳定的基础,是土地可持续利用的前提。就目前的土地可持续利用评价来看,在内容上,多注重区域土地功能在时间上的变化,对土地利用的空间格局关注较少；在评价方法上,多以线性加权方法为主,而一些新的综合评价方法,如神经网络方法、投影寻踪综合评价方法等,还没有在土地可持续利用评价中得到很好的应用。恩施土家族苗族自治州是湖北省唯一被划入西部大开发的地区,是鄂西生态文化旅游圈的重要组成部分。随着宜万铁路、沪蓉高速公路西段的开通,加上西部大开发的推进和鄂西生态文化旅游圈的建设,必将会极大地促进区域的社会经济发展,也给区域土地利用带来前所未有的压力。区内目前生态环境良好,但属于典型的生态脆弱区,生态环境一旦遭到破坏,将很难恢复。因此,在该区域开展土地可持续利用评价,了解目前土地利用所处的状况,找出土地可持续利用的限制因子,提出可持续利用对策,对实现区域土地可持续利用、实现区域可持续发展具有重要意义。本文首先对景观空间格局变化与土地可持续利用评价的关系进行理论探讨。人们的土地利用行为形成特定的景观空间格局,景观空间格局是土地利用的结果。首先,景观与土地在空间实体上具有相似性。人类的经济开发活动主要是在景观层次上进行的,景观为人类经济活动提供各种资源及场所,是人类的开发利用对象。而从土地的角度,土地是人类的基本生产资料,为人类的生产和生活提供场所和空间,人类所有的生产和生活都要落实到土地上,表现为土地利用行为及土地利用方式的时空变化。因此,景观是土地利用的结果。景观类型和土地利用类型、景观结构与土地利用结构、景观功能与土地功能、景观变化与土地利用／覆被的变化间具有极大的相似性。其次,从空间格局的演变上看,短时间尺度下,人类的土地利用行为是空间格局演变的主要驱动因子。土地是一个自然地理综合体,是一个由不同土地利用类型组成的空间镶嵌体,具有明显的空间异质性。一般认为,一定范围内异质性的增强有助于提高景观稳定性,而空间镶嵌稳定性是功能稳定性的基础。根据生态整体性与空间异质性理论,区域土地可持续利用的实质就是构建合理的空间异质性,维持土地利用的生态整体性。土地可持续利用评价不能局限于分析其构成要素的状况,而是要把握系统整体特征,综合考虑影响土地利用的社会因素、经济因素和生态因素等各种因素进行评价。景观结构与功能理论指出：“格局反衍过程,过程反衍机理,机理揭示规律”,景观结构决定着景观的功能。对区域土地利用来说,土地可持续利用即土地功能的延续和维持,就是要追求土地功能的稳定,而功能稳定又以景观空间镶嵌稳定性为基础。因此,土地可持续利用评价不仅对土地功能强弱进行评价,还必须评价其景观空间格局(土地利用空间结构),尤其是要对景观空间格局的稳定性进行评价。在景观空间格局稳定性定量评价方面,因空间异质性是空间格局稳定性的基础,般选择描述空间异质性的相关指标来对景观格局的稳定性进行评价。在此基础上提出基于景观空间格局的土地可持续利用评价思路：土地可持续利用就是区域土地在面临特定压力的情况下,能够稳定的、持续的获得较高综合效益以满足人类社会经济系统的需求,而这种土地功能的稳定性以土地空间镶嵌的稳定性为基础。因此,基于景观空间格局的土地可持续利用评价就是对区域土地面临的压力、土地的景观空间结构和综合效益的综合评价。压力是土地利用可持续性变化的驱动因子,综合效益最优是土地可持续利用的最终目标,景观空间镶嵌的稳定性是实现土地可持续利用的基础。基于景观空间格局来进行土地可持续利用评价,不仅可以实现结构和功能的结合,还可以将时间和空间耦合起来。在探讨景观空间格局演变与土地可持续利用评价之间关系的基础上,以ETM+和TM遥感影像、SRTM DEM遥感数据为数据源,综合运用“3S”技术及景观生态学方法研究恩施土家族苗族自治州1990年年以来的土地变化及空间格局演变,对其产生的生态环境影响(包括净第一性生物生产力、生态系统服务价值、生态足迹及水土保持效益)进行定量评估,建立起基于景观空间格局的“压力—功能—结构”土地可持续利用评价指标体系,对研究区1990年以来土地利用的持续性进行评价和障碍因子诊断。研究表明：1)自1990年以来,区域土地利用发生了较为剧烈的变化,其最主要的变化为草地和耕地的急剧减少,林地的持续增加,空间格局聚集性持续增强,多样性下降,空间格局的稳定性持续降低。从数量变化上看,1990年～2000年,变化幅度从大到小排序依次为：林地(7.92%)>草地(-6.20%)>耕地(-2.19%)>水域(0.23%)>建设用地(0.23%),水域与建设用地变化的比例相同,但水域变化的面积更大。2000年～2007年,变化幅度从大到小排序依次为：耕地(-8.41%)>林地(8.17%)>草地(-0.14%)>建设用地(0.11%)>水域(0.06%)。从变化强度上看,两个研究时段相比,2000年～2007年土地变化强度更大。1990年～2000年,土地利用的综合动态度为6.06%,各土地利用类型的变化强度按从大到小排序为：水域(11.51%)>草地(-9.42%)>建设用地(2.11%)>林地(1.51%)>耕地(-0.55%)。2000年～2007年,区域土地利用综合动态度为9.83%,各土地利用类型的变化强度按从大到小排序为：草地(-5.23%)>耕地(-3.19%)>水域(1.95%)>林地(1.94%)>建设用地(1.09%)。从土地利用类型的空间分布上看,从1990年以来,土地利用类型空间分布的基本变化趋势是：草地持续向高山收缩,林地持续往低海拔地区蔓延,耕地进一步向低海拔沟谷地回缩。从1990年到2000年,耕地分布的平均高程下降25.92米,平均坡度下降1.24度；草地分布的平均高程增加了474.73米,平均坡度上升了1度左右。2000年～2007年,林地分布的平均高程下降5.23米,平均坡度下降0.98度；耕地分布的平均高程下降96.99米,平均坡度下降0.97度。草地分布进一步往高山收缩,平均分布高程增加124.73米。从区域土地利用的空间格局上看,自1990年以来,空间格局的聚集度持续增大,多样性指数持续下降,空间格局的稳定性不断降低。从1990年到2000年,区域土地的利用的斑块数量从244128变为383276个,平均斑块面积从9.91公顷变小为6.31公顷，平均形状指数、分维数和分形指标趋大,土地利用空间格局趋于复杂化,破碎化；优势度和均匀度分别从1990年的0.7561、0.5302变化2000年的0.8522和0.4705,反应区域土地利用格局受林地和耕地两种用地类型的支配作用加强。景观聚集度增大,空间格局的多样性指数降低。从2000年到2007年,区域土地的利用的斑块数量从383276个变为185722个,平均斑块面积从6.31公顷变变为13.03为公顷；优势度和均匀度分别从2000年的0.8522、0.4705变化2007年的0.9867和0.3869,聚集度进一步提高,反应区域土地利用格局受林地和耕地两种用地类型的支配作用进一步得到加强,空间格局的多样性指数进一步降低。2)由于人口的增加和土地利用结构的调整,土地的生态承载能力有所降低,但总体上区域土地利用的生态环境效益持续提高。从面积加权平均的NPP来看,研究区域的净第一性生产力持续增加,1990年区域平均NPP为15.78t／(hm2·a),2000年上升到15.86 t／(hm2·a),2007年上升到16.63 t／(hm2·a)。各用地类型的NPP按大小基本排序为林地>耕地>草地>建设用地>水域。从单位面积NPP极值上看,1990的NPP极值为83.43 t／(hm2·a),2000年和2007的NPP极值均为98.87t／(hm2·a),说明研究期内生态环境的改善不仅仅表现在森林覆盖率的持续提高上,森林的生长情况也变得更好,其生物生产功能变得更强。生态系统服务价值评估的结果显示：研究区域自1990年以来,生态系统服务价值持续增长,表明区域生态环境质量得到持续改善,生态系统服务功能得到增强。从土地利用类型上看,林地和耕地构成区域生态系统服务价值来源的主体,其中又以林地的生态系统服务价值最大,并随时间推移得到加强。恩施州土地利用的生态系统服务价值1990年为3140522.2万元,2000年增长为3402427.2万元,2007年进一步增加到3662663.9万元。在生态系统服务价值的构成中,林地的生态系统服务价值最高,所占比例最大并逐渐增大；其次是耕地,但所占比例逐年下降。林地生态系统服务价值占区域总生态系统服务价值的比例1990年为77.85%,2000年味82.73%,2007年进一步增加到87.28%；耕地生态系统服务价值占区域总生态系统服务价值的比例1990年为18.72%,2000年将为16.33%,2007年进一步下降至11.78%。从生态足迹上看,自1990年以来,区域人均生态足迹持续增加,而人均生态承载持续下降,1990年略有生态盈余,随后转为生态赤字。1990年人均生态足迹为1.23hm2,2000年为1.44 hm2,2000年上升为2.2 hm2。两个时段相比较,2000以后人均生态足迹上升速度更快。其中,能源消费的生态足迹占据较大比重,并迅速上升。人均生态承载能力持续降低,1990年人均生态承载为1.447 hm2,200年降为1.3846 hm2,2007年进一步下降为1.2203 hm2。区域水土流失评价的结果表明,由于区域极高的森林覆盖率,研究区内水土流失轻微,水土保持效益良好。土壤侵蚀模数最大值1990年为694.947 t／km2·a,2000年为693.507t／km2·a,2007年为670.764 t／km2·a。根据土壤侵蚀分类分级标准,1990年以来研究区域土壤流失状况总体上为微度侵蚀,土壤轻度流失的面积1990年为558.9公顷,2000年为243.81公顷,2007年为230.04公顷。以轻度土壤流失面积最大的1990来看,其面积占区域土地总面积的比例仅万分之二。3)分别采用均方差决策赋权法、熵权法确定土地可持续利用评价指标权重,用线性加权方法进行区域土地可持续利用综合评价,并与投影寻踪综合评价方法评价结果进行比较印证,得到区域土地利用可持续性变化为：自1990年以来,研究区域土地利用的可持续性持续下降。土地可持续利用评价的障碍诊断表明：1990年,土地可持续利用的主要障碍因子是粮食单产水平较低,区域生态环境相对较差。1990年以后,随着区域内封山育林措施和国家退耕还林政策的实施,生态环境得到持续改善,土地可持续利用的主要限制因素为建设用地面积的增长、人口综合消费水平的提高和景观多样性的下降。其深层次的原因则是因为退耕还林使耕地、草地大量转变为林地,一方面使得区域生态环境进一步改善；另一方面直接导致区域土地的生态承载能力降低和空间格局的稳定性下降。最后,本文提出了区域土地可持续利用的对策：加强基本农田的建设,保护耕地,推行土地整理,提高耕地的产出能力；节约集约利用建设用地,控制建设对耕地的占用；抓住机遇进行产业结构调整；根据景观生态学集中于分散原理,构建生态安全格局：建立区域生态补偿机制,维持退耕还林政策的连续性。更多还原

【Abstract】 Land, as one of the most important resources for human survival and development, is the carrier of human existence and the place where all human activities of production and living take place. For good man-land relationship and sustainable use of land resources are the basis for economic and social sustainable development, it is of great significance that the relationship between man and land should be well coordinated and use of land should be sustainable. Evaluation for sustainable land use is the key problem and an inevitable part in the research of the sustainable land use from theory to practice, it works as an important means of implementing sustainable land use, and it is an important basis for the renovation of regional land, the planning for land use and the formulation of the land use system. "Structure decides function", the stability of the spatial mosaic of land is the foundation of the stability of land function, and it is also the premise of sustainable land use. On the evaluation contents of sustainable land use, the researches in this area currently mainly emphasis on the multi-temporal changes of land functions, but the spatial pattern of land use draws less attention in the study field. On the evaluation merhods of sustainable land use, the current researches mainly take the linear weighting method, but some new evaluation methods, such as neural network method, projection pursuit comprehensive evaluation method and so on, have not been well applied so far.Enshi Tujia and Miao Autonomous Prefecture is the only region in the Great Western Development in Hubei Province, it is an important part of the Western Hubei Eco-cultural Tourism Circle. With the Yichang-Wanzhou railway opened and the western section of Shanghai-Chengdu Expressway opened, the advance of Great Western Development and the construction of Western Hubei Eco-cultural Tourism Circle will certainly give a boost to the social economy of this area and brings unprecedented pressure to the regional land use at the same time. Currently, the region keeps a good ecological environment, but belongs to typically ecological fragile areas, thus, the ecological environment, once damaged, will be difficult to restore. Therefore, it is of great significance to achieve regional sustainable development to develop evaluation for sustainable land use in this area, identify the current situation of land use, find out the limiting factors of sustainable land use, and put forward countermeasures to realize regional sustainable land use.This paper first discusses theoretically about the relationship between the changes of spatial patterns of landscape and evaluation for sustainable land use.The regional people’s behavior of land-use forms a particular landscape spatial pattern; landscape spatial pattern is the result of land use. Firstly, from the perspective of spatial entity, landscape and land have great similarities. Human economic activities are mainly carried out at the landscape level, the landscape provides a variety of resources and sites for human economic activities and it is the objection for human beings to use and develop. Whereas, land is a fundamental means of production for human beings, and it provides venues and space for human production and life. All human life and production must be implemented in land reflected as spatial and temporal changes in human behavior and way of land-use. Therefore, the landscape is the result of land use. There exist great similarities between landscape types and land-use types, landscape structure and land-use structure, landscape function and land function, landscape changes and land use/cover changes. Secondly, the perspective of evolution of spatial pattern, at short time-scale, human behavior of land use is the main driving factor for the evolution of spatial pattern.Land is a synthesis of physical geography, a composition of different land use types in the space mosaic and is of obvious spatial heterogeneity. It is generally believed that the heterogeneity is enhanced in a certain range can help to improve the stability of landscape, while the stability of space mosaic is the base for the stability of function. According to the theories of ecological integrity and spatial heterogeneity, the essence of regional sustainable land use is to construct a reasonable spatial heterogeneity and to maintain the ecological integrity of land use. Evaluation for sustainable land use should not be limited to analyze the constituent elements, but to grasp the features of the system as a whole and to have a comprehensive consideration of social, economic and ecological factors to evaluate. On regional land use, sustainable land use is the continuation and maintenance of land function, which requires seeking the stability of the land function, while the stability of land function is based on the stability of landscape spatial mosaic. Therefore, evaluation for sustainable land use is not only mainly on the land function, but also on the landscape spatial pattern (spatial structure of land use), especially on the stability of the landscape spatial pattern. In the aspect of quantitative evaluation for the stability of landscape spatial pattern, for the spatial heterogeneity is the basis for the stability of spatial pattern, relevant indicators of spatial heterogeneity are generally used to evaluate the stability of landscape pattern.On this basis, this paper puts forward the evaluation for sustainable land use based on landscape spatial patterns as follows: Sustainable land use means that the regional land can bring about steady, sustainable and high comprehensive benefits in face of certain pressure to meet the needs of the human socio-economic system, whereas the stability of the land function is based on the stability of land spatial mosaic. Therefore, evaluation for sustainable land use based on landscape spatial patterns is the integrated evaluation of the pressure, landscape spatial structure and the comprehensive benefits. Pressure is the driving factor for the change of the sustainability of land use, the optimal comprehensive benefits are the ultimate goal of sustainable land use, and the stability of landscape spatial mosaic is the basis for achieving sustainable land use. To carry out the evaluation for sustainable land use based on landscape spatial patterns can not only achieve the combination of structure and function but also the coupling of time and space.Based on the research of the relationship between landscape spatial patterns and evaluation for sustainable land use, this paper comprehensively uses "3S" technologies and Landscape ecology approach based on data sources of ETM+and TM remote sensing images, SRTM DEM remote sensing data to study the change of land and the evolution of spatial pattern since 1990, and carry out quantitative assessments of the ecological environmental impact (Including net primary biological productivity, the value of ecosystem services, ecological footprint, and benefits of soil and water conservation). On this basis, the paper establishes an index system of evaluation for sustainable land use, applying the "3S" technologies sustainable use based on landscape spatial patterns of "pressure-function-structure" of study area, and gives assessments for the sustainability of land use in this region since 1990 and undertakes a comprehensive diagnosis of obstacle factors to put forward specific countermeasures for the sustainable use of land.The research shows that:1.Landscape ecological principles bring about new.requirements for the method, criteria and approach in the evaluation for sustainable land use. On the method of evaluation for sustainable land use, it is to take into comprehensive consideration of social factors, the economic factors and ecological factors on land use, and to put land use systems on the context of regional sustainable development and grasp the characteristics of overall system to do evaluations by taking into consideration of various factors. On the criteria of sustainable land use, it is to pursue an integrated optimization in the ecological, economic, social and aesthetic benefits rather than economic benefit maximization of a single cost-effective. On the approach to the technical evaluation, the essence of regional sustainable land use is the continuing construction of spatial heterogeneity and the dynamic maintain of ecological integrity. In Sustainable land use, it is required to keep the stability of the landscape, evaluation for sustainable land use is to evaluate not only the function of land but also the landscape spatial pattern (spatial structure of land use). The growth of human population and the economic and social development will promote human beings to strengthen land use, change their behavior of land use in space and way so as to derive sufficient output to sustain the population survival and the development of social economy, leading to the evolution of landscape patterns. Therefore, evaluation for sustainable land use based on landscape spatial patterns is actually the comprehensive evaluation of the pressure on regional land, landscape spatial structure and overall comprehensive benefit. Pressure is the driving factor of sustainability of land use changes driving comprehensive benefits, the optimal is the ultimate goal of sustainable land use, the stability of the spatial mosaic of landscape is the basis for achieving sustainable land use. Based on landscape spatial pattern, evaluation for sustainable land use can realize not only the combination of the structure and function but also the coupling of time and space.2.Since 1990, great changes have taken place more rapidly in the use of regional land, the major change is the sharp decline in grassland and cultivated land. With the continuing growth of wood land, the aggregation of spatial pattern has continued to improve, and the diversity to decline, thus the stability of spatial patterns has a consistent decline.From the perspective of changes in number during 1990～2000, the magnitude of changes in descending order were as follows:woodland (7.92%)> grassland (-6.20%)> arable land (-2.19%)> waters (0.23%> construction land (0.23%).The proportion of changes in waters and construction land are the same, but the area of waters has a bigger change. From 2000 to 2007, the magnitude of changes were as follows:arable land (-8.41%)>woodland (8.17%)> grassland (-0.14%)> construction land (0.11%)> waters(0.06%).From the perspective of the intensity of land-use changes to compare the two study periods, the intensity of land changes in the period from the year of 2000 to 2007 is more severe. From 1990 to 2000, the dynamic intensity for the regional comprehensive land-use is 6.06%, and the intensity of land-use changes by descending order is as follows:waters (11.51%)> grassland (-9.42%)> construction land (2.11%)> woodland (1.51%)> arable land (-0.55%).From 2000 to 2007, the dynamic intensity for the regional comprehensive land-use is 9.83%, the intensity of land-use changes by descending order is as follows:grassland (-5.23%)>arable land (-3.19%)> waters (1.95%)>woodland (1.94%)>construction land (1.09%).From the perspective of spatial distribution of land-use types, since 1990, the basic trend to the spatial distribution of land-use types is:the grassland continues to shrink to the mountains, woodland continues to spread to the low- altitude areas and the arable land further continues to back upon the low- altitude gully land. From 1990 to 2000, the average elevation of arable land distribution fell 25.92 meters with an average slope of 1.24 degrees decreased, the average elevation of grassland distribution increased 474.73 meters with an average slope of 1 degrees increased. From 2000 to 2007, the average elevation of woodland distribution fell 5.23 meters with an average slope of 0.98 degrees decreased, the average elevation of arable land distribution fell 96.99meters with an average slope of 0.97 degrees decreased, and grassland continues to shrink to the high mountains, with an average elevation in the distribution of 124.73 meters increased.From the perspective of spatial pattern of regional land use, since 1990, the aggregation degree of spatial pattern continues to increase with the diversity index continuously declining and the stability of spatial pattern diminishing. From 1990 to 2000, the patch number of the regional land use increased from the number of 244128 to 383276, and the average patch area decreased from 9.91 hectares to 6.31 hectares. Mean shape index, Fractal dimension and fractal indicators are big, and the land-use spatial patterns becomes more complicated and fragmentation. The richness and evenness change respectively from 0.7561 and 0.5302 in 1990 to 0.8522 and 0.4705 in 2000, which indicates that the dominant role of the two land-use types of woodland and arable land that affected regional land use pattern is enhanced. The aggregation degree of landscape is further improved, the dominant role of the two land-use types of woodland and arable land is further enhanced and the diversity index of the spatial pattern is further reduced.3.Due to the growth of population and the restructuring of land use, the ecological carrying capacity of land has been decreased, but generally the eco- environment benefits of the regional land use continues to be improved.From the perspective of Area-weighted average NPP, the net primary productivity in the study area continued to increase,in 1990, the regional average NPP was 15.78t/(hm2·a), in 2000, the regional average NPP rose to 15.86t/(hm2·a), and in 2007, the regional average NPP rose to 16.63 t/(hm2·a). The land types of NPP sorted by the size are:woodland> arable land> grassland> construction land> waters. From the NPP Maximum in per unit area, the NPP Maximum in 1990 was 83.43 t/(hm2·a), the average NPP Maximum in 2000 and 2007 are 98.87 t/(hm2·a),thus the improvement of the ecological environment during the study period leads to not only the continuous growth of the forest coverage rate, but also brings better growth situation to the forest and makes biological production functioning better.The results of the value evaluation for ecosystem services show that:since the year of 1990, the value of ecosystem services in the study area keeps growing, which shows that the quality of the ecological environment in this region is continuously improved and the function of the ecosystem services is improved. From the perspective of the land-use types, woodland and arable land are the region’s main parts in forming the value for the regional ecosystem services, the value of wood land eco-system services takes up the maximum and is to be strengthened over time.From the perspective of ecological footprint, since the year of 1990, the regional per capita ecological footprint continues to grow, while the per capita ecological capacity continues to decline, the study area had slight ecological surplus in 1990, and then it had ecological deficit. In 1990, the per capita ecological footprint was 1.23hm2, in 2000, it was 1.44 hm2, and it rose to2.2 hm2 in 2007. Compared the two periods, the rise in per capita ecological footprint is faster after 2000. Among them, ecological footprint of energy consumption takes up a large proportion in the whole ecological footprint and it grows rapidly. The per capita ecological capacity continues to decline, in 1990, the per capita ecological capacity is 1.447 hm2, and it dropped to 1.3846 hm2 in 2000, and it continuously reduced to 1.2203 hm2 in 2007.The evaluation results of the soil erosion in this region show:due to the high coverage of forests in the study area, the soil erosion is slight, and the conservation benefits of soil and water are good. The maximum modulus of soil erosion was 694.947 t/km2-a in 1990, it was 693.507 t/km2-a in 2000, and was 670.764 t/km2-a in 2007. According to the criteria of soil erosion classification and grading, the overall situation of soil erosion in the study area was slight-erosion since 1990. The area of soil loss was 558.9 hectares in 1990,243.81 hectares in 2000 and 230.04 hectares in 2007. Taking the largest area of soil loss in 1990 for consideration, the area of soil loss takes up only 2/10000 in the proportion of the total land area in the study area.4. The sustainability of regional land use in the study area has continuously been declining since 1990. The major obstacle factors of sustainable land use in 1990 were the low level of grain production and the relatively poor regional eco-environment. After 1990, with the adoption of Forest Conservation Measures and the Policy of Converting arable land to Forestry in the region, the ecological environment continues to be improved. The major limiting factors of sustainable land use are the growth of construction land, the increasing of population composite consumption level and the declining of landscape diversity.Finally, this paper puts forward the countermeasures for regional sustainable land use:first, to strengthen the construction of basic farmland, protect arable land, implement land management and improve the output capacity of arable land; second, to use construction land economically and intensively and control the occupation of construction land on arable land; third, to seize the opportunity to carry out industrial restructuring and apply the Principle of decentralization of Landscape Ecology to constructing ecological security pattern; and at last, to establish regional ecological compensation mechanism and adhere to the continuity of the Policy of Converting arable land to. Forestry.更多还原