Carbon Sink Effects in Conversion of Farmland to Forest Project in Karst Drainage Basin——A Case of Hongfenghu Drainage Basin in Guizhou Province

[Objective]Study on carbon sink effects in Conversion of Farmland to Forest Project in Hongfenghu drainage basin in order to provide evidences for assessing carbon sink potential of conversion of farmland to forest in Guizhou Province.[Method]By investigating the implement of Conversion of Farmland to Forest Project in Hongfenghu drainage basin from 2000 to 2006,the carbon sink amount and effect of seven main tree species in the foreat region like Cunninghamia lanceolata,Cryptomeria fortunei,Amygdalus persica,Prunus salicina,Armeniaca vulgaris,Camptotheca acuminate and Catalpa bungei were calculated,based on which the amount of forest carbon sinks in Hongfenghu drainage basin in 2015 was estimated.[Result]Biomass storage and carbon sink amount in middle and young aged forests were increasing over time from 2000 to 2006,which reached 1.05×107 kg by 2006 and would engage more and more potential.Cunninghamia lanceolata has the superior carbon sink capacity in the seven tree species in the research region,of which the amount of carbon sink per unit area will be 106.51 t/hm2 by 2015,followed by Cryptomeria fortunei with the amount of carbon sink per unit area by 99.42 t/hm2.Armeniaca vulgaris has the weakest carbon sink capacity of all the seven species with the amount of 13.03 t/hm2.The total amount of carbon sink in seven tree species was 2.35×107 kg,while the average amount of carbon sink per unit area was 26.17 t/hm2,which could produced economic benefit of 7.17×106 yuan calculated on the price of 305.0 yuan/t or 5.91×106 yuan calculated on the price of 254.1 yuan/t.[Conclusion]Economic benefits of carbon sink effects of Conversion of Farmland to Forest Project in Hongfenghu drainage basin were great with huge appreciation potential.

Future Development Direction of the Restoration of Mountains,Rivers,Forests,Farmlands,Lakes,and Grasslands and the Faced Problems

In this paper,the definition,connotation,and internal relationship of mountains,rivers,forests,farmlands,lakes,and grasslands in China are elaborated,and the current situation of ecological restoration projects for mountains,rivers,forests,farmlands,lakes,and grasslands was introduced.Moreover,the problems that have arisen in the specific implementation process of pilot projects were analyzed,such as unclear target positioning,inaccurate analysis of ecological problems,insufficient engineering design systematicness,weak operability of evaluation standards,and weak coordination in engineering management.The development direction and major needs for the protection and restoration of mountains,rivers,forests,farmlands,lakes,and grasslands in the future have been proposed from four aspects:theoretical research,engineering design,effect evaluation,and monitoring and supervision.

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.

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.

Application of the Modified Neighborhood Interference Model to the Cultivation of Forest and Herbaceous Ecosystem

This paper is an extension of the application of neighborhood interference model--being modified--to the study of the interference between forest plants and herbaceous plants. The exploration of the neighborhood interference between triploid Populus tomentosa and Lolium multiflorum shows that the interference of Lolium multiflorum on triploid populus tomentosa is positive, with the primary interference factor living weight, and secondary factor cover degree; the growth of an individual tree is affected by the number, height, and coverage of the Lolium multiflorum; the more dense the coverage of the Lolium multiflorum in a certain area, the taller, faster and more trees will grow as a result of a greater positive neighborhood interference. The modified neighborhood interference model well serves as an effective approach to extend the application of neighborhood interference researches.

The Development Process,Current Situation and Prospects of the Conversion of Farmland to Forests and Grasses Project in China

The Conversion of Farmland to Forests and Grasses Project is the most symbolic and globally important ecological engineering effort to build the human and natural life community.After the call and mobilization stage since the founding of the People’s Republic of China,the first round of Conversion of Farmland to Forests and Grasses occurred at the end of the 20 th century.With the second round of Conversion of Farmland to Forests And Grasses launched in 2014,the central government has invested 535.3 billion yuan altogether by 2020,and 34.83 million ha have been returned to forest and grassland in 25 provinces(autonomous regions and municipalities)(2435 counties included).Among them,14.23 million ha were returned from farmland;barren hills and wasteland afforestation accounted for 17.53 million ha;and sealed mountain forest cultivation represented 3.07 million ha,accounting for 40%of the total afforestation area of national key projects in the same period,and 41 million households and 158 million farmers benefited directly.The project construction has made great achievements.The total value of ecological benefits has reached 1.42 trillion yuan,plus economic benefits of 0.26 trillion yuan,and social benefits of 0.73 trillion yuan,for a total amount of 2.41 trillion yuan.This effort has made outstanding contributions toward building an ecological civilization and a beautiful China.Looking forward to the future,the Conversion of Farmland to Forests and Grasses will embark on a new stage of high-quality development,which will strive to achieve high-quality construction,high efficiency and a high level of management.China will promote the third round of conversion of farmland to forest and grassland from 2021 to 2035,and it is expected to return 6.67 million ha to forests and grasses.

Review of Conversion of Farmland to Forests Project:Ranking First in Investment in the World

The Conversion of Farmland to Forests Project (CFF) is one of the six great forest ecological Projects inChina and one of the ten great forest ecological Projects in the world, ranking the third in overall scale and the first ininvestment. CFF was officially initiated in 2002, covering 1897 counties (county-level cities and districts) in 25provinces (autonomous regions or municipalities) of China. The whole investment is more than 40 billion US$ duringabout 20 years (from 1999 to 2017), aiming to form better ecology system in fragile ecology regions and effectivelycontrol the soil and water erosion of the Yangtze and the Yellow River and sandstorm of the Three-north Regions inChina. The experimental Project of CFF began in 1999, including Sichuan, Shanxi and Gansu province, and the scopeof CFF was widened later. About 1.16 million ha of farmlands were converted to forestlands, and one million ha ofplantation in mountains and wasted lands were completed in 3 years, involving 20 provinces (autonomous regions andmunicipalities), 400 counties, 27 thousand villages, 5.7 thousand towns, 4.1 million farm families and 16 millionfarmers.

Farmland to Forest Conversion Suspended

Due to a lack of farmland,a reforestation project in its eighth year has been tem- porarily suspended

基于自然的山水林田湖草沙一体化保护和修复技术路径探索

研究目的:探索将基于自然的解决方案(NbS)融入山水林田湖草沙一体化保护和修复工程实施全过程的理论框架、技术路径,对其全过程技术体系和适应性管理进行研究,为科学推进工程实施提供理论基础和技术参考。研究方法:文献梳理、对比分析和归纳总结。研究结果:(1)山水工程实施的全过程应围绕NbS准则和指标要求,在调查评价、规划设计、工程实施和管理维护全过程融入NbS理念,以有效指导工程实施;(2)将NbS作为山水工程的理论指引,应针对特定生态问题和修复对象,识别关键修复要素并选择对应工程技术;(3)串联关键生态系统要素、贯通区域(流域)—保护修复单元—场地三个尺度是将NbS融入山水工程,推动全要素、多尺度、多层级治理的实现路径。研究结论:将NbS准则融入山水工程调查评价、规划设计、工程实施和管理维护全过程,是保证山水工程实施成效的关键,需尽快完善相关理论和实践研究、形成具体标准和范式,推动生态系统整体保护、系统修复和综合治理。

贵州省赤水市大同河流域山水林田湖草生态保护修复工程研究

本文通过收集大同河流域的基础地理、环境地质、林业资源、生物多样性等相关资料,分析了该区域的生态系统特征和生态服务功能,对该区域的自然资源和生态环境进行了深入调查。结合生态系统的类型、结构、功能及受损状况,识别出生态系统中存在的主要问题。根据大同河流域的特点,将空间区域划分为不同的功能区,并针对关键生态环境问题及实现人与自然和谐共生的治理目标,提出了生态保护修复工程的布局和措施建议。

黄河中游不同地貌条件下植被干旱时空特征及影响因素

利用归一化植被指数、地表温度和降水数据构建温度植被降水干旱指数(TVPDI)分析黄河中游2000—2021年植被干旱时空特征及影响因素,论证了黄河中游退耕还林还草工程实施与区域植被干旱特征间的关系。结果表明:①黄河中游2000—2021年多年平均TVPDI值呈不显著上升趋势,TVPDI多年均值为0.708,对应干旱等级为轻旱。②黄河中游2000—2021年TVPDI有较强的空间分异性,呈现“东北、西南部地区旱情较轻,西北、东南部地区旱情较重”的空间分布格局;从各地貌分区来看,黄土高塬沟壑区旱情较轻,风沙区与河谷平原区旱情较重。③黄河中游TVPDI空间分异的主要影响因子为气温、蒸散发和降雨量,且与TVPDI存在显著线性关系。黄河中游2000—2021年植被覆盖度与蒸散发量均呈增加趋势,土壤水分呈下降趋势。

基于MODIS/NDVI的陕北地区植被动态监测与评价

陕北地区从1999年退耕还林试点工程实施以来,区域植被发生很大变化,退耕前后植被动态变化监测成为退耕还林工程评价任务之一,而当前植被恢复监测评价的难点在于如何确定哪些是由于退耕而引起的植被变化。针对此问题,选取适合陕北地区植被变化监测的MOD IS/NDVI数据,利用均值变化及趋势分析方法,从不同土地利用/覆被类型和不同坡度植被指数动态变化两方面分析退耕还林对植被动态变化的影响。结论如下:(1)陕北地区平均NDVI从2000—2008年呈现较明显的增长趋势,坡耕地和草地NDVI增长速度相对较快;(2)趋势分析结果显示,陕北绝大部分地区植被恢复良好,植被指数呈明显改善的面积占整个地区面积的64.96%,中度改善占18.58%,其中又以坡耕地、草地植被明显改善面积分别占陕北地区明显改善面积的45.43%和17.10%,坡耕地对陕北地区植被明显改善面积贡献最大;(3)7-15°、15-25°及25-35°坡度植被明显改善面积分别占总改善面积的39.91%、25.81%、2.28%,其中7-25°坡度植被明显改善面积占总面积的65.72%;(4)基于陕北地区近年气候呈暖干化发展趋势,同期降雨并未呈现显著变化,说明非气候因子中退耕还林等人为因素是引起NDVI增长的主要因素,退耕还林对于陕北地区植被恢复有明显促进作用。

岷江上游生态补偿的博弈论

为了建立合理的生态补偿机制,制定更为科学的生态补偿政策,以岷江上游退耕还林补偿为例,运用博弈论模型考察了岷江上游现有生态补偿机制,以及在补偿政策实践过程中补偿主体与补偿对象之间的决策和行为过程。结果表明:(1)长期来看,生态补偿政策的实施效果不完全在于补偿金额的大小,仅仅依靠提高对生态建设者(保护者)的补偿标准来保护环境是不明智的;(2)生态补偿年限对岷江上游地区生态补偿政策的实施效果起着重要作用,政府制定生态补偿政策时应该将补偿年限纳入政策制定范畴中,并作为重点考虑的因素;(3)岷江上游地区第三产业的发展水平及生态建设者(保护者)外出务工收入水平的高低直接影响生态建设工程实施的效果;(4)对生态补偿的重要策略是应该通过建立相应的配套措施来增加农民务工的机会。

粮食安全:西北地区退耕对粮食生产的可能影响

据西北五省区制定的规划或计划,到2010年将累计退耕400×104hm2,约占现有耕地面积的1/4。按照目前的单产水平和粮食作物比例,西北地区将减少粮食产量近400×104t,相当于1996年西北地区粮食总产量的1/8。同时,退耕对当地的粮食生产存在正面影响,主要表现在:①退耕节省下来的生产要素的转移可以带来未退耕耕地粮食产量提高;②西北地区生态环境以及局地小生境的改善可以促进粮食生产、降低灾害风险。此外,农业科技进步和工程设施建设的加强,会对保留耕地上的粮食生产起到极大的推动作用。通过对西北五省区粮食单产的预测并结合人口预测可知,2010年西北地区粮食总产量可达4516.9×104t,在人均400kg、425kg和450kg水平下粮食需求分别为3936.1×104t、4182.1×104t和4428.1×104t。因此,从长远的角度来看,就西北地区整体而言将不会出现粮食短缺,但粮食盈余水平较低;而就具体省区而言,陕西、甘肃和青海三省区必须通过粮食调入才能满足本省区需求,而新疆和宁夏粮食则有一定盈余。

中国退耕还林工程及其所产生的影响

回顾了中国退耕还林工程的进展情况。利用在6省15县72乡镇225个行政村和3375个样本农户跟踪调研数据,及全国统计数据,分析了退耕还林工程对粮食生产、农民收入、土地利用结构等方面所产生的影响。讨论了中国农民积极参与退耕还林工程的主要原因。认为退耕还林工程与粮食产量联系密切,增加农户的收入不平等。建议政府部门制定比较完善和可供操作的退耕还林规划,划定两个工程区统一补贴的方法有待改进,能够够继续推进退耕还林工程,适度调整已有退耕还林工程区,适度向贫困户倾斜;可以考虑取消大户承包政策等。

晋西黄土区退耕还林22年后林地土壤物理性质的变化

退耕还林林地土壤物理性质的变化,是评价退耕还林措施及其生态效益的重要内容之一。选取晋西黄土区退耕22年后形成的3种典型乔木林分,包括自然恢复的辽东栎林、油松刺槐人工混交林和刺槐人工纯林,并以耕地作为对照,通过外业调查和采样分析,从深度和程度两方面研究了退耕还林对土壤容重、土壤总孔隙度和毛管孔隙度等物理性质的影响,结果表明:(1)就土壤容重而言,自然恢复林80 cm以上土层较耕地有显著变化(P<0.05),平均降低了28.78%,变化程度最大的在10—20 cm土层;人工林较耕地显著变化发生在60 cm以上土层,混交林和纯林分别降低了10.58%和8.34%,变化程度最大的土层为20—40 cm;(2)3种退耕林地土壤总孔隙度在80 cm以上较耕地发生显著增加(P<0.05),增加程度表现为自然恢复林(35.53%)>混交林(15.04%)>纯林(13.68%),20—40 cm土层变化程度最大;(3)土壤毛管孔隙度自然恢复林、混交林和纯林分别达到耕地的1.36,1.13和1.12倍,自然恢复林和人工林显著变化土层分别为80 cm和60 cm以上,变化程度最大的均为40—60 cm处;(4)土壤有机质和粘粒含量对土壤理化性质影响显著。对于土壤容重、总孔隙度和毛管孔隙度的变化,有机质的增加可解释31%以上,而粘粒含量的解释度则达到44%—51%,均为极显著水平(P<0.01)。自然恢复林对于土壤物理性质影响程度和影响土层深度都大于人工林。

光皮桦细根与扁穗牛鞭草草根分解的土壤微生物数量及优势类群

通过室内模拟试验研究向土壤添加单一光皮桦直径为0～1mm细根（处理1）、1～2mm细根（处理2）、扁穗牛鞭草草根（处理3）、0～2mm细根与扁穗牛鞭草草根混合物（处理4）分解过程中土壤微生物数量以及微生物优势类群的变化。结果表明，120d后，与未加植物根系的对照相比各处理都显著的增加了土壤微生物的数量，其中细根、草根混合处理的微生物总数大于添加单一细根和草根的处理（P〈0．05）。真菌在分解过程中占主要地位，其次是放线菌，最后是细菌。对土壤微生物进行分离、纯化、鉴定出参与细根、草根分解初期的主要优势类群是假单胞菌属（Pseudomonas）、木霉菌属（Trichoderma）、游动放线菌属（Actinoplanes），在培养后期（120d后）起主要作用的优势类群是芽孢杆菌属（Bacillus）、曲霉属（Aspergillus）、青霉属（Penicillium）、链霉菌属（Streptomyces）、诺卡氏菌属（Nocardia）。8种土壤微生物优势类群数量在分解过程中未表现出明显的变化规律，但分解120d后，各处理优势类群的数量显著大于对照（P〈0．05）。由此可见，细根、草根的不同处理对其分解过程中土壤微生物数量及种类有较大影响，不同的分解阶段发育着不同的土壤微生物。

延河流域退耕前后土壤侵蚀强度的变化

根据修正通用土壤流失方程,在ArcGIS软件平台下,以黄土高原延河流域为例,在合理选用和计算修正通用土壤流失方程中各因子参数的基础上,计算并分析陕北黄土高原延河流域退耕前后土壤侵蚀量的变化及其动态分布。结果表明:1)延河流域退耕后,土壤侵蚀明显减少,与1986—1997年相比,退耕后至2000年土壤侵蚀量平均减少34%;2)坡耕地对土壤侵蚀影响明显,尤其是陡坡耕地退耕至关重要;3)在修正通用土壤流失方程各因子中,短期内影响土壤侵蚀动态变化的主控因子是植被覆盖管理因子,所以调整土地利用结构是减少土壤侵蚀的有效方法。

坡耕地退耕还林后的植被恢复

Public welfare forest is the most important model of vegetation restoration in the Conversion of farmland to forests in Sichuan Province. It can well represent and reflect the characteristics and laws of vegetation restoration in hillside fields. Therefore an Alnus cremastogyne forest community developed via converting hillside fields to forest, was investigated by contrast with a weed community on abandoned hillside fields. The results indicated that: 1) In Sichuan Basin and surrounding regions of it, vegetations restored so rapid that the average DBH (diameter at breast height), tree height of A.cremastogyne tree crown density, ground vegetation coverage respectively reached 5.2 cm, 6.1 m, 0.7 and 100 percent for 3 years and after converting hillside fields to forest. 2) With vegetation restoring, community gradually developed mosaic spatial pattern and vertical stratification, simultaneously distribution of plant population changed from regular to clumped, and spatial heterogeneity of community increased. 3) Community biodiversity remarkably increased in the process of vegetation restoration in hillside fields. During the period, species richness of both commnuities changed from 20 to 39, Shannon-Wiener diversity index was 4.205 and 5.021 respectively, while Pielou equitability index dropped little. 4) Plant species frequently and dramatically altered, which mainly showed that therophytes declined rapidly from 16 to 10, while perennial ones dramatically increased from 2 to 26, and 8 of them are phanerophytes. 5) The pathway of community development approximately was from annual herbs to shrubs + perennial herbs to trees + shrubs and herbs + perennial herbs, finally to natural mixed forests, such driving force was mainly from interspecific competition.

近20年黄土高原不同地貌类型区植被覆盖变化及原因分析

植被覆盖是控制或加速水土流失最敏感的因子。以黄土高原为研究对象,利用1988—2005年NOAA/AVHRR植被指数(NDVI)月最大值合成的7月份资料分析不同地貌类型区NDVI值的时空变化规律,并通过计算NDVI值与同期降雨量的相关系数分析降雨量对不同地貌类型区NDVI的影响,探讨黄土高原典型区县退耕还林政策对NDVI的影响。结果表明:1)黄土高原整体植被覆盖度较低,NDVI多年平均值为0.29,平原区、石质山地、黄土低山、黄土塬及其周围地区NDVI值在0.30～0.40之间,梁、卯、片沙黄土丘陵区NDVI值在0.18～0.22之间,其余地貌类型区均低于0.15;2)1998年之后8年NDVI的平均值比前10年的NDVI平均值略有增加,整体增加幅度为4.5%,不同地貌类型区NDVI值变化表现出明显的地带性,呈东北西南走向,黄土高原主体部分中的黄土塬、黄土破碎塬、梁状黄土丘陵均增加10%以上,峁状黄土丘陵、风蚀沙化丘陵略有减少,减少的区域没有增加的区域大;3)除石质山地、黄土低山和平原地区外,其他地貌类型区7月最大NDVI值与5—7月累计降雨量存在很好的相关性,R2在0.60以上;4)地处梁状黄土丘陵区的吴旗县,1998年后形成了一个明显的以县为边界的NDVI值增长区,增幅达40%,远远高于该地貌类型区的平均增长值14%。初步结论:除平原地区外,降雨量决定黄土高原植被覆盖度的空间分布,1998年前后黄土高原植被变化的决定因素是降雨量;吴旗县的实例证明,只要水土保持资金到位、林草建设因地制宜、管理保护措施完善,退耕还林政策将会对植被覆盖度的增加起到积极作用。