Multi-scales Analysis of Driving Forces on Land Use/Cover Change in China:Taking Farmland Returning to Forest or Grassland as a Case

Increasing populations are causing an increase in food demands, and the area of cultivated land expands every year. Inappropriate land transition from ecology to production results in the constant decline of the ecological security level and influences the regional sustainable development. Adjusting unreasonable land use mode and reconstructing natural land cover are important ways to maintain and improve the ecological environment. Also reclaiming farmland as areas for forests and grasslands (FRFG) is another way. Successful implementation of FRFG in China is the result of comprehensive effect of the multi-scales driving forces. This paper analyses the driving forces of FRFG in China on a national (country) –regional (province) – local (county) – household (farmer) level scale, and the results are: driving forces at the national scale include ecological and food security and the western development of China; at the regional scale, ecological and economic benefits become the main factors to influence the dimension of FRFG under the same policy. The driving forces can be divided into 6 types: industrial structure adjustment, water source protection, flood prevention, the Three-Gorge Project protection, reduction of the amount of sediment flowing into the Yellow River and wind erosion desertification prevention. The driving forces at the local scale can be divided into 12 types with developing leading industries, increasing farmers’ income and improving agricultural production conditions as the main types; at the household scale, the nationalpolicy meeting farmers’ demands and the optimization of individual interests are all driving forces.

Evaluation of the Land Production Potential in the Context of Returning Farmland to Forest in Karst Region:A Case Study of Guizhou Province

In this paper, we take Guizhou Province (the heart of southwestern Karst region in China) as the research object. By establishing gray forecasting model and time series forecasting model, we conduct the accuracy test on the actual production capacity of land and the forecasted production capacity of land in 2007 and 2008, and then conduct comprehensive forecast of the land production potential in Guizhou Province in 2020. On this basis, considering the nutritional standards needed by three kinds of life type (dressing warmly and eating one's fill, well-off life, relatively affluent life), we evaluate the land production potential in Guizhou Province under the project of returning farmland to forest. Based on the evaluation results, we put forth the relevant recommendations for achieving sustainable land use in the context of returning farmland to forest in Guizhou Province.

Thoughts and Practice of Ecological Protection and Restoration of Mountains, Rivers, Forests, Farmlands, Lakes and Grasslands

The report of the 19th National Congress of the Communist Party of China stated that it was necessary to establish and practice the concept that lucid waters and lush mountains are invaluable assets,treat the ecological environment as life,and coordinate the management of mountains,rivers,forests,farmlands,lakes and grasslands.In recent years,China has organized a series of pilot projects for the ecological protection and restoration of mountains,rivers,forests,farmlands,lakes and grasslands,breaking the boundary between administrative divisions,departmental management and ecological elements,and implementing conservation and restoration oriented towards the improvement of ecosystem services,so as to solve the problem of the lack of overall planning for ecological protection and restoration projects and the separated management of ecological elements.This study systematically elaborated the theoretical basis and connotation characteristics of ecological protection and restoration of mountains,rivers,forests,farmlands,lakes and grasslands.It proposed the implementation path of ecological protection and restoration project of mountains,rivers,forests,farmlands,lakes and grasslands by taking the water source conservation area of Beijing-Tianjin-Hebei as a case,so as to provide reference for the implementation and decision-making management of ecological protection and restoration projects in various regions.

Returning Farmland to Forest, Forest Management and Permanent Forest : Thinking on High-quality Development of Returning Farmland to Forest

In the first round of returning farmland to forest,many places in Hubei Province have vigorously developed ecological forests dominated by pine,fir and cypress,to improve the fragile ecological situation as soon as possible.At present,this kind of ecological forests are facing the dilemma of more pure forests,higher density and less management,with worse economic benefits.To realize high-quality development of these stands,it is necessary to carry out forest management guided by the close-to-nature concept.These stands will be transformed into permanent forests with multi tree species,multi age classes,multi levels and continuous coverage,to realize organic unity of economic,ecological and social benefits.

Monitoring and Evaluation of Benefits of Project of Returning Farmland to Forests in Henan Province

The project of returning farmland to forest has been implemented and consolidated in Henan Province for 20 years.At present,it is in a critical transition period when the previous round of project of returning farmland to forests has completed and a new round of project of returning farmland to forests has started.Henan Province took counties(cities)with different representations as sample counties for monitoring the benefits of project of returning farmland to forests(key monitoring areas in Henan Province),and monitored social and ecological benefits every year,and has obtained real and scientific monitoring data.

Tree Productivity and Water Potential Productivity in Returning Farmland to Forest Project in Datong County, Qinghai Province

From 2002 to 2003, based on the investigation of sample plots and stem analysis of remained plantation communities in the areas of returning farmland to forest in the 1980s in Datong County, Qinghai Province, this paper studies tree productivity and moisture potential productivity of six types of plantations on the land of returning farmland to forest, such as green poplar (Populus cathayana Rehd.) and shrub mixed forest, Asia white birch (Betula platyphylla) and China spruce (Picea asperata) mixed forest, Dahurian larch (Larix gmelinii) pure forest, China spruce pure forest and Asia white birch pure forest and so on. The results show that: in sub-humid region of Loess Plateau, 3 000 trees per hm2 is a proper standard of planting density. Under current condition, the productivity index of green poplar and shrub mixed forest, Asia white birch pure forest, China spruce pure forest, and Asia white birch and China spruce mixed forest with the density of 2 1003 333 trees per hm2 can serve as potential productivity standard of actual biomass of arbor established forest. In sub-humid area, Thornthwaite Model is adopted to estimate plant climate potential productivity, which is about 8 462 kghm2穉1. The actual potential water productive efficiency of Purplecone spruce (Picea purpurea) and Asia white birch pure established forest are 17.22 and 22.14 kgmm1hm2穉1 respectively, and that of green poplar and shrub mixed established forest, and Asia white birch and China spruce mixed established forest are 21.14 and 19.09 kgmm1hm2穉1 respectively. The potential productivity of green poplar and shrub mixed forest, Asia white birch and China spruce mixed forest, China spruce pure forest and Asia white birch pure forest which have grown into forest with the density of 3 000 trees per hm2 have attained or been close to that of local climax community, which is local maximum tree productivity at present. These types of forestation models are the developing direction of the returning farmland to forest project.

Effects of Different Modes of Returning Farmland to Forest on Physicochemical Properties of Soil in Bashang Area of Northern Hebei Province

[Objective]The research aimed to understand the change rules of physicochemical properties of soil in the different modes of returning farmland to forest.[Method]The physicochemical properties of soil in three different types of returning farmland to forest(Hippophae rhamnoides Linn.forest,Caragana korshinskii forest and Ulmus pumila L.forest)were analyzed by taking the enclosed grassland as comparison in Bashang area of northern Hebei Province.[Result]The results showed that there were significant differences among different types.Order of the bulk density of soil:H.rhamnoides Linn.forest(1.17 g/cm^3)<U.pumila L.forest(1.24 g/cm^3)<C.korshinskii forest(1.26 g/cm^3)<enclosed grassland(1.61 g/cm^3);order of the total porosity of soil:H.rhamnoides Linn.forest(55.29%)>U.pumila L.forest(52.55%)>C.korshinskii forest(51.93%)<enclosed grassland(38.85%);order of the organic matter content of soil:H.rhamnoides Linn.forest(3.191%)>C.korshinskii forest(3.128%)>U.pumila L.forest(2.804%)>enclosed grassland(2.536%).[Conclusion]After returning farmland to forest,vegetation played a positive role in physicochemical properties of soil.There were significant differences in physicochemical properties of soil among different modes of returning farmland to forest,and the improvement effect of H.rhamnoides Linn.forest on physicochemical properties of soil was the best.

Estimation of Relative Ecological Value of Returning Farmland to Forest & Mountain Enclosure for Grazing Prohibition——A case study in Yongxing Township of Jingyuan County,Gansu Province

[Objective]Returning farmland to forest and mountain enclosure for grazing prohibition ecological effect and economy rationality were explored.[Methods]A case study of returning farmland to forest and barren hills grazing prohibition in Yongxing Township of Jingyuan County was used to discuss and estimate the relative ecological function and relative ecological value.[Results]1)The ecological value of the forest of returning farmland was far more than the sum of the ecological value of farm crops and the agricultural output,and also more than the national subsidy standard.So the state policy of returning farmland to forests is not only favorable to local eco-environment restoration,but also reasonable in economic development.2)The ecological value of mountain enclosure for grazing prohibition was less than the opportunity cost of prohibiting grazing,also less than the national subsidy standard.The sum of the relative ecological value of prohibiting grazing and the state subsidies was more than the opportunity cost of prohibiting grazing.However,the ecological value of new vegetation through returning farmland to forest project was greater than the China's average ecological value of grassland.[Conclusion]The relative ecological value can be used to solve the problems in the equivalent conversion among various ecological indexes and between ecological indexes and economic indexes.

Eco-environment Restoration and Regional Differentiation Characteristics Based on “Building Terrace and Returning Slope Farmland to Forests and Grass”

Based on the scientific and technological achievements in the past decade in the Loess Hilly-gully Region and the successful demonstration experience in Yan'an Yangou watershed, we summarize the characteristics of eco-environment restoration pattern based on "building terrace and returning slope farmland to forests and grass". According to the data on land use, slope farmland and the agricultural population in 1999, we calculate the area of new terrace that needs to be built, the area of garden plot that needs to be extended, vegetation restoration area and investment demand in counties (cities, districts). Establishing and using some indicators, such as basic farmland extension indicator, garden plot extension indicator, vegetation restoration index and investment demand density, we conduct type classification and analysis of regional differentiation characteristics in 55 counties (cities, districts). The results show that in the Loess Hilly-gully Region, 691 600 hm2 of new terrace needs to be built, 792 000 hm2 of economic forests and orchards need to be extended, 5 410 200 hm2 of vegetation needs to be restored, and the total investment demand is 15.82 billion yuan; in terms of geographical distribution, obviously there are two key areas for eco-environment restoration (one is located in the border area between northern Shaanxi and northwestern Shanxi, and the other is located in the eastern Gansu and southern Ningxia area); the classified regional guidance policies should be formulated as soon as possible, and the limited funds should be concentrated in the key areas.

退耕还林地生态环境损害评估案例分析及应用

近年来,随着我国经济的高速发展,林地生态环境损害事件日益增加。不同类型的生态系统或同一生态系统在不同区域所提供的生态服务功能侧重均不同,鉴定评估林地生态系统的环境损害价值时应选用不同的测算方法。通过阐述理论公式法和实际监测法的原理和适用范围及其在生态环境损害评估中的应用,并对量化过程中参数的选取原则与方法进行说明。结合案例分析非法占用退耕还林地导致的生态环境损害范围和程度,计算出2012年~2019年的生态环境损害价值量为205万元。研究退耕还林地生态环境损害典型案例,并将其推广应用于小规模普通林地,对林地生态环境损害案件的鉴定评估环节具有重要引领作用。

塔河胡杨林核心区退耕地初始年土壤及植被养分特征数值分析

【目的】研究塔河中下游胡杨林核心区退耕地初始年土壤和植被的养分特征,为胡杨林公益林核心区退耕地生态恢复提供基础支撑数据。【方法】以塔河中下游胡杨林核心区退耕地初始年的土壤和植被为研究对象,运用“S”形布点法、野外标准木全株收割法、多点混合方法分别采集植被和土壤样品,结合室内测定植被和土壤养分特征数值进行分析。【结果】(1)土壤养分含量和植被营养成分积累量均集中分布在Ⅳ区和Ⅴ区。(2)土壤垂直深度上,养分集中在表层土壤,且随着土层深度增加,土壤养分含量依次递减,但是在60~100 cm土层处,呈现小幅增加。不同样地与不同土层深度之间土壤养分含量差异显著(P<0.05)。(3)不同样地中残存棉花(棉秆、根系)及草本植物中全N、全P、全K、有机碳含量均有显著差异(P<0.05)。【结论】胡杨林自然保护区核心区退耕地初始年土壤养分含量较高,有利于荒漠植被群落的生长和发育,提高群落演替速率,有利于塔河胡杨林退耕地植被恢复与环境变化及其相互作用、生态过渡带植被恢复与区域生态稳定。

浙江省钱塘江源区域山水林田湖草生命共同体健康评价

[目的]分析浙江省钱塘江源区域山水林田湖草生命共同体健康状况,为国土空间规划和生态管理提供科学参考。[方法]基于生命共同体理论与活力—组织力—恢复力(vitality-organization-resilience,VOR)生态模型理论,构建生命共同体健康评价指标体系。利用3S技术和社会经济统计资料,以县域为评价单元,对钱江源区域山水林田湖草生命共同体的健康状况进行评价和分级。[结果]①2020年,钱江源区域的淳安县处于生命共同体健康状态,建德市、开化县、常山县生命共同体均为亚健康状态。②2015—2020年4个县(市)生命共同体健康指数总体呈上升趋势,健康指数上升趋势大小依次为:建德市>常山县>淳安县>开化县。③2020年,4县(市)中山水林田湖草子系统健康状态最好的为常山县,最差的为淳安县;生态系统健康状态最好的为淳安县,最差的为常山县。④钱江源区域林、田子系统结构及其生态服务功能有待提升优化。⑤生态修复试点工程对于提升钱江源区域生命共同体健康状态在一定程度上起到了积极的推动作用。[结论]钱江源区域山水林田湖草生态修复工程取得了阶段性成果。4县(市)接下来应针对山、水、林、田、湖等子系统的不同问题开展相关修复工作,同时进行统筹规划与生态整治,实现山水林田湖草生命共同体系统的统筹共治、健康管理与持续经营。

科尔沁地区山水林田湖草沙一体化保护和修复的应用与研究

鉴于科尔沁地区干旱少雨、风沙侵扰的脆弱生态环境特征和半农半牧的社会经济特点,遵循山水林田湖草沙一体化治理理念,坚持保护优先、自然恢复为主,人工辅助的原则,以水资源承载能力为约束条件,突出生态效益并兼顾经济效益。结合工程规模大、管理及协调难度高等特点,探索总结山水林田湖草沙一体化保护和修复工程的实施模式、关键工序、应用技术,对未来生态保护工程EPC模式应用、林草机械融合信息技术升级、“星-空-地”一体化空间发展等发展趋势提出一些建议,以期为后续类似林草生态工程建设提供参考。

山水林田湖草系统治理理论与方法综述

针对不同区域山水林田湖草存在问题,寻求适宜的系统治理方法至关重要。国内外运用最为广泛的山水林田湖草系统治理的理论与方法主要有基于自然的解决方法(NbS)、再野化、景感生态学、生态安全格局和生态系统服务5种,但目前对这些理论与方法的相互联系和区别尚不清晰。从定义及发展、准则、实施方法和典型案例等方面系统梳理了山水林田湖草系统治理的5种理论与方法并进行比较,结果可知,5种理论与方法运用生态系统的恢复力和适应性,通过自然恢复和人为干预等手段,使退化或者破坏的生态系统回归到一种稳定、健康、可持续的发展状态,但它们在人为干预程度、适用范围、与人类关系的密切程度及农业应用等方面有差异。认识到山水林田湖草系统治理不同理论与方法的特点、适用性和局限性,结合治理区域的特点和问题,针对性地选择治理方法,为山水林田湖草系统治理理论和实践提供参考。

都匀市刺梨产业发展现状及对策探讨

于2023年4月对都匀市2013-2022年刺梨基地发展现状进行调查,了解基地抚育管理及挂果情况,并分析刺梨鲜果产量、销售及加工状况,总结刺梨产业发展存在困难、问题。结果表明:都匀市刺梨基地发展主要有3种方式,一是退耕还林(刺梨),其中以2017年造林面积最大;二是企业流转土地后纳入其他林业工程营造刺梨,以巩固退耕还林成果项目造林面积最大;三企业流转土地自己出资营造刺梨,主要集中在2015-2017年,造林面积达到8376亩。刺梨基地营建后普遍存在抚育管理次数少,挂果少问题。2019-2022年,刺梨鲜果产量呈逐年上升趋势,主要采收区为平浪镇、墨冲镇,销售则以个体户收购后倒卖外县刺梨加工厂为主。指出了都匀市刺梨产业发展存在诸多问题,如总体种植规模小、缺乏持续资金投入、后续抚育管理未跟上等,应结合刺梨产业发展现状及时作出调整。

西北干旱荒漠地区退耕还林还草工程综合效益评价

为对西北干旱荒漠地区新一轮退耕还林还草工程的实施提供科学指导,以吐鲁番市为研究区域,建立包含表征该区域特点的15个指标的综合效益评价指标体系,基于云模型与变异系数法组合确定指标权重,运用比重法无量纲化指标数据,采用加成综合法进行退耕工程综合效益评价分析,并通过灰色系统预测模型GM(1,1)对2021—2025年生态效益、经济效益、社会效益和政策响应指数进行了预测。结果表明:(1)在2004—2019年,综合效益指数逐年提高,新一轮退耕提升幅度是前一轮的两倍。(2)森林覆盖率提高、水土流失治理面积扩大、农民人均纯收入增加和人均林业产值增加,是生态效益和经济效益提高的主要因素。(3)退耕工程的实施促使产业结构和就业结构呈良性发展趋势。退耕所涉农户再退耕意愿的提升巩固了退耕成果,使其具有长效性。(4) 2021—2025年的生态效益、经济效益、社会效益和政策响应指数预测值均呈上升趋势,且经济效益指数>政策响应指数>生态效益指数>社会效益指数。依据预测结果,西北干旱荒漠地区在新一轮退耕工程的实施中应以生态建设为重点,加强生态补偿和乡村振兴战略的有效衔接,促进农业转移人口市民化,实现生态、经济、社会和政策响应间的协调发展。

国有林区森工企业土地利用动态变化研究

基于遥感数据和GIS技术,以龙江森工集团和伊春森工集团所属40个国有森工企业为研究对象,剖析不同时期土地利用类型动态变化,结合土地利用转移变化规模和方向的时空差异,探讨国有林区土地利用变化与经济社会发展转型新形势、新问题之间的关系。研究结果表明:⑴2006—2019年间黑龙江省国有林区天然林生态保护修复成效显著,林地面积增加了3.379 185万hm~2,动态度达到29.48%;⑵2014—2018年土地利用类型间转移最为频繁,除林地、水域和未利用地外,所有土地都存在用地竞争;⑶2006—2020年生态用地向建设用地转出面积约是建设用地向生态用地转出面积的2.10倍;⑷伊春森工集团的土地利用转移变化程度比龙江森工集团更稳定;⑸生态用地增加较多的国有森工企业总产值相对更高。

新一轮退耕还林还草工程对土地利用效率的影响——基于黄河流域的实证研究

[目的]分析新一轮退耕还林还草工程实施对黄河流域土地利用效率的影响机制与政策效果,为深刻理解土地利用效率与持续推进退耕还林还草工程提供理论参考。[方法]以黄河流域新一轮退耕还林还草工程政策实施作为自然实验,采用包含非期望产出指标的Super-Window-DEA模型测度土地利用效率,采用双重差分模型与中介效应模型分析政策效果与传导途径。[结果](1)2009—2020年黄河流域69个城市的土地利用效率略有下降,上游(0.546 5)和下游(0.419 9)的土地利用效率高于中游(0.279 5);(2)新一轮退耕还林还草工程显著抑制了土地利用效率的提高,且政策的负向影响存在异质性,同时,经济发展和人口密度也分别促进和抑制土地利用效率;(3)耕地所占比例与财政支出是新一轮退耕还林还草工程影响土地利用效率的中介变量,且耕地比例是部分中介。[结论]建议在肥力较差、劳动力投入匮乏的土地上推进退耕还林还草工程,鼓励黄河流域各城市开展未利用土地的开荒复绿工作,后续退耕还林还草工程实施过程中根据流域之间土地利用的不同功能开展黄河流域上中下游之间、流域内城市之间的生态补偿,并充分借助信贷资金,引入生态产业化发展,推动绿色产业升级,探索退耕还林还草工程生态补偿的新模式。

灵宝市退耕还林工程阶段性监测与评价

对灵宝市退耕还林工程持续17年的效益监测表明:退耕还林工程的顺利实施,有效促进了工程区森林资源持续增长、粮食安全不断巩固、林业产值不断提升、退耕农户生活条件明显改善。

碳中和背景下国内外陆地生态系统碳汇评估方法研究进展

研究目的:针对近30年森林、草地、农田、湿地4种生态系统主流碳汇核算方法,辨析各核算方法特点以准确地对陆地生态系统碳汇能力现状和未来碳汇潜力进行评估。研究方法:文献综述法、对比分析法和归纳法等。研究结果:(1)现有碳汇核算方法多基于公式模型计算,在进行植被碳汇空间格局分析时受样本数量、测量误差、参数误差、数据来源不一致、模型普适性差等因素影响,计算结果存在不确定性,中国统一标准的陆地生态系统碳汇监测体系亟待建立;(2)实现陆地生态系统碳汇量的准确计算,需要可靠数据源、合理的模型与计算方法、多途径的交叉验证、适当误差分析与插补校正;(3)应有效整合样地勘察、模型构建、微气象学和遥感监测等方法,评估陆地碳库的现存量与容量,揭示碳库稳定性及综合考虑碳库影响因素,以期解决生态系统多尺度耦合问题。研究结论:未来研究重点应基于大量实测数据,探究分类型、分地域、分气候的差异化碳汇核算方法,建立全尺度、广覆盖的碳汇计量模型,为中国陆地生态系统碳汇核算标准提供参考。