Agroforestry systems: sources of sinks of greenhouse gases?

The prominent role of forestry and agroforestry systems in the flux and long-term storage of carbon (C) in the terrestrial biosphere has increased global interest in these land-use options to stabilize greenhouse gas (GHG) emissions. Preliminary assessments suggest that some agroforestry systems (e.g., agrosilvicultural) can be CO₂ sinks and temporarily store C, while other systems (e.g., ruminant-based silvopastoral systems) are probably sources of GHG (e.g., CH₄).Agroforestry systems can be significant sources of GHG emissions, especially at low latitudes. Practices such as tillage, burning, manuring, chemical fertilization, and frequent disturbance can lead to emission of CO₂, CH₄, and N₂O from soils and vegetation to the atmosphere. Establishment and management of agroforestry systems incompatible with prevailing edaphic and climatic conditions can accelerate soil GHG emissions. Non-sustainable agroforestry systems are quickly degraded, and woody and herbaceous crops can become significant GHG sources. Silvopastoral systems can result in soil compaction and erosion with significant loss of labile C and N compounds to the atmosphere. Ruminant-based silvopastoral systems and rice paddy agrisilvicultural systems are well documented sources of CH₄ which significantly contribute to the global CH₄ budget.Early assessments of national and global terrestrial CO₂ sinks reveal two primary beneficial attributes of agroforestry systems: 1) direct near-term C storage (decades to centuries) in trees and soils, and, 2) potential to offset immediate GHG emissions associated with deforestation and subsequent shifting agriculture. Within the tropical latitudes, it is estimated that one ha of sustainable agroforestry can provide goods and services which potentially offset 5–20 ha of deforestation. At a global scale, agroforestry systems could potentially be established on 585–1275×10⁶ ha of technically suitable land, and these systems could store 12–228 (median 95) Mg C ha^–1 under current climate and edaphic conditions.The US Government right to retain a non-exclusive, royalty free licence in and to any copyright is acknowledged.     

我国森林碳库特点与森林碳汇潜力分析

森林生态系统在稳定全球碳循环和缓解全球气候变暖方面发挥着重要的作用,合理发展林业,可以实现固碳增汇,是缓解全球气候变化的重要措施。综述了森林碳库的重要地位、我国森林生态系统碳库特点,分析了通过增加森林面积和提高森林经营水平来增加森林碳汇的潜力。     

Developing Carbon Sequestration Forestry for Mitigating Climate Change: Practice and Management of Carbon Sequestration Forestry in China

By elaborating the functions and effects of forestry in mitigating climate change, introducing the concepts and significance of forest carbon sink, forestry carbon sequestration, and carbon sequestration forestry, and summarizing the practices of carbon sequestration forestry in China, the paper came up with the outline for strengthening the management of carbon sequestration forestry, i.e. implementing the Climate Change Forestry Action Plan, reinforcing the accounting and monitoring of national forest car...     

Carbon storage in agroforestry systems in the semi-arid zone of Niayes,Senegal

Agroforestry is an ancient practice widespread throughout Africa. However, the influence of Sahelian agroforestry systems on carbon storage in soil and biomass remains poorly understood. We evaluated the carbon storage potential of three agroforestry systems (fallow, parkland and rangeland) and five tree species (Faidherbia albida, Acacia raddiana, Neocarya macrophylla, Balanites aegyptiaca and Euphorbia balsamifera) growing on three different soils (clay, sandy loam and sandy) in the Niayes zone, Senegal. We calculated tree biomass carbon stocks using allometric equations and measured soil organic carbon (SOC) stocks at four depths (0–20, 20–50, 50–80 and 80–100 cm). F. albida and A. raddiana stored the highest amount of carbon in their biomass. Total biomass carbon stocks were greater in the fallow (40 Mg C ha^?1) than in parkland (36 Mg C ha^?1) and rangeland (29 Mg C ha^?1). More SOC was stored in the clay soil than in the sandy loam and sandy soils. On average across soil texture, SOC stocks were greater in fallow (59 Mg C ha^?1) than in rangeland (30 Mg C ha^?1) and parkland (15 Mg C ha^?1). Overall, the total amount of carbon stored in the soil + plant compartments was the highest in fallow (103 Mg C ha^?1) followed by rangeland (68 Mg C ha^?1) and parkland (52 Mg C ha^?1). We conclude that in the Niayes zones of Senegal, fallow establishment should be encouraged and implemented on degraded lands to increase carbon storage and restore soil fertility.     

Carbon storage in southern boreal forests following fire

>Changes in carbon (C) after fire were measured in seven southern boreal upland forest stands during the five immediate post‐fire years and 23 years after the fire. Pre‐fire above‐ground C mass of the stands was estimated. Combustion losses were 19% of the pre‐fire above‐ground C mass (8.4 kg m^?2), and an additional 4% of that C mass was lost in the following 3–4 years. After 23 years, neither C mass of understory (0.1 kg m^?2) nor standing snags (0.3 kg m^?2) differed from that estimated before the fire; tree C was less (2.4 vs. 6.0 kg C m^?2), and forest floor (2.5 vs. 1.4 kg C m^?2) and coarse woody debris (1.7 vs. 0.7 kg C m^?2) C were higher. Above‐ground C mass was 84% of pre‐fire mass. There were no measured changes in surface soil C following the fire (2.9 kg C m^?2). Total C mass, including surface soil, was 10.2 kg m^?2 at 23 years or 91% of the estimated pre‐fire C. Although gross fluxes of C followed the fire, massive net losses of C did not occur either immediately or in the two decades after fire. Dynamics of C differed among the stands. Data from either a single stand or a chronosequence in space can lead to different conclusions than those derived from multiple stands through time.     

人工林碳储量影响因素

人工林在固定大气CO₂及减缓全球气候变化中扮演着十分重要的角色, 是实施碳减排计划最主要的媒介之一。人工林的碳汇作用被认为是减缓全球变化的一种可能机制和最有希望的选择而成为全球变化减缓研究的核心内容之一。人工林碳储量受自然条件、人类活动、林分状况等因素的影响。因此, 人工林碳储量动态及过程、人工林碳汇功能与人工林经营与管理、人工林碳汇与碳贸易等是未来全球变化和林业生态工程研究的重点内容。     

广东森林火灾碳排放及应对气候变化策略

森林是生态系统中重要的碳库。森林火灾将森林中存储的碳重新释放至大气中,对全球气候变化产生重大影响。文章介绍了国内外森林火灾碳排放及其计量技术,对广东森林火灾碳排放进行估测,评价了森林火灾对气候变化的影响,并指出广东应对气候变化的森林防火对策。     

广东省林业碳汇发展的思考

介绍了广东省林业碳汇发展的现状,指出了其中存在的一些问题,如森林质量不高、森林生态效益补偿标准低等;提出了加大林业碳汇的宣传、建立统一的碳汇计量和监测体系、加强科学研究等建议,以促进广东省林业碳汇的发展。     

基于全球气候变化谈判的森林碳汇研究

为进一步了解森林生态系统的碳汇功能和国际气候谈判,通过查阅资料,对全球气候变化以及CO2的温室效应、气候谈判的现状、实质以及主要发达国家温室气体的减排动态进行了简单的总结.就森林生态系统的碳汇潜力,碳汇作用的非持久性问题进行了探讨.综述了不同时期森林生态系统碳汇研究的成果以及国际森林碳汇项目的动态.分析了森林碳汇项目实施过程中存在的主要问题,并提出我国在国际气候谈判、温室气体减排和造林、再造林等林业碳汇项目中应采取积极立场和应对措施.     

减少森林砍伐和退化机制中的碳评估探讨

涉及森林的气候行动能够最直接地降低大气二氧化碳的增长速度, 并可以最低代价赢得在其他工业部门发展减排技术的时间。通过在发展中国家实施REDD+, 能够显著地减少温室气体排放。在监测、报告和核查(MRV)温室气体排放上存在的技术问题, 以及渗漏、额外性和永久性等政策问题, 是REDD+程序中最主要的障碍。为了实现全球气温升高不超过2℃临界点的目标, 需要国际体系和组织、各国政府和私营部门发挥重要的作用, 需要各国加强建设监测、报告、核查森林碳储量的能力, 需要开发和利用地面测量碳储量计算模型和卫星遥感数据判读转化技术。文中介绍了对实现REDD+可能有重大贡献的国际体系和组织的最新动态以及国家级MRV系统的特征, 探讨了实现全球森林碳评估的途径以及卫星数据在森林碳评估中的应用等, 提出了我国在参与REDD+活动中存在的挑战和应该采取的对策。     

我国森林管理参考水平制定方法的分析

森林管理参考水平的制订是今后气候变化研究的重要内容之一.文中通过总结森林管理的相关定义和森林管理参考水平的制定要求, 讨论附件Ⅰ缔约方在制定森林管理参考水平过程中存在的问题, 结合森林现状分析我国在森林管理参考水平制定过程中将面临的困难, 提出我国森林管理参考水平的制定应包括3个方面的研究内容, 即预测延长森林轮伐期的森林碳储量变化量、木质林产品的碳储量变化量和不可抗力(如火灾、病虫害、暴风雪等)引起的森林碳储量变化量, 三者的加和即为森林管理碳汇活动参考水平.     

全球气候变化与森林碳汇研究概述

以变暖为主要特征的全球气候变化不仅严重影响了经济社会的可持续发展,并日趋国际化、政治化而成为世界各国当今面临的最重大挑战之一,对此国际社会高度重视并积极采取各种措施,其中,通过林业活动增加森林碳汇(减缓碳释放)是重要途径.此外,研究表明通过森林固碳来减缓碳释放不仅潜力巨大,而且具明显的成本优势,更主要的是这种方法不会对...     

银杏复合经营对土壤碳、氮、磷和有机质的影响

以江苏东台林场银杏+小麦(G+W)、纯银杏(G)和纯小麦(W)经营模式为研究对象,对不同土层(0~5,≥5~15,≥15~30和≥30~50mm)的p H、微生物量碳、微生物量氮、硝态氮和铵态氮、全氮、速效磷、全磷和有机质进行了系统的测定。结果表明:不同经营模式对土壤p H没有显著的影响,但对土壤微生物量碳、微生物量氮、硝态氮、全氮、速效磷、全磷和有机质等影响显著。G+W经营模式有较高的土壤微生物量碳、微生物量氮、硝态氮、全氮、速效磷、全磷和有机质。因此,银杏复合经营系统能够更好地维持土壤肥力,利于土地可持续经营。     

中国林业应对气候变化碳管理之路

首次全面系统介绍了中国林业应对气候变化工作特别是近十几年来碳汇管理的发展历程和创新实践, 包括阐述林业碳汇的理论研究及其成果, 简介成功实施全球首个CDM项目的经验和中国首个应对气候变化公募基金会——中国绿色碳汇基金会的建立与运行以及碳汇交易试点, 总结中国林业碳管理标准体系的研究、成果和碳汇营造林项目的国内实践, 提出今后中国林业碳管理的政策建议。     

减少毁林和森林退化引起的排放:一个综述视角的分析

减少因毁林和森林退化引起的温室气体排放(REDD)对控制和减缓全球气候变暖具有重要作用。UNFCCC第11次缔约国会议将REDD议题列入气候谈判议程, 希望REDD成为2012年后承诺期减缓气候变化的重要措施之一。文中在对国际社会关于REDD的谈判进展和指导原则等进行概述的基础上, 探讨了当前国际社会关注的REDD的焦点问题, 分析了这些焦点问题的现状及其可能的发展趋势, 并据此提出讨论和建议。     

Carbon sequestration: An underexploited environmental benefit of agroforestry systems

Agroforestry Systems - Agroforestry has importance as a carbon sequestration strategy because of carbon storage potential in its multiple plant species and soil as well as its applicability in...     

不同森林经营措施对木材产量和碳储量的影响

在应对全球气候变化中, 林业具有特殊地位和重要功能, 以社会、经济和环境可持续发展为目标的森林可持续经营是全球趋势。文中阐述了森林在减缓和适应气候变化中的独特作用; 重点分析了不同营林措施对木材产量和碳储量的影响, 并结合可持续林业的发展趋势评价了不同经营模式框架下木材产量与碳储量之间的平衡; 针对全球气候变化对森林生态系统带来的挑战, 探讨了今后森林经营措施的研究重点和难点, 旨在为制定合理的经营方案提供理论依据。     

Carbon stock of Banja forest in Banja district,Amhara region,Ethiopia: An implication for climate change mitigation

This study estimates the carbon stock of Banja Forest which is natural and dry Afromontane forest type in Banja District, northwest of Ethiopia. A systematic sampling method was used to identify each sampling point through the Global Positioning System. A total of 63 plots measuring 20 × 20 m were employed to collect tree species and soil data. Losses on ignition and the Walkley–Black method were used to estimate biomass and soil carbon stock, respectively. The carbon stock of trees was estimated using an allometric equation. The results revealed that the total carbon stock of the forest was 639.87 t/ha whereas trees store 406.47 t/ha, litter, herbs, and grasses (LHGs) 2.58 t/ha and soil 230.82 t/ha (up to 30 cm depth). The carbon pools’ carbon stock variation with altitude and slope gradients were not significant (p > 0.05) which was similar to other previous studies. The Banja Forest is a reservoir of high carbon and thus acts as a great sink of the atmospheric carbon. It can be concluded that the Forest plays a role in climate change mitigation. Hence, it should be integrated with reduced emission from deforestation and degradation (REDD⁺) and the clean development mechanism (CDM) of the Kyoto Protocol to catch monetary benefits.     

陆地生态系统扰动与碳循环模拟研究进展

陆地生态系统扰动（火灾、病虫害、氮沉降、极端气候事件等）可以极大影响并改变生态系统的功能与结构,进而对陆地碳循环的时空格局产生重要影响。定量估算自然扰动对陆地生态系统的影响对于深入理解陆地生态系统循环过程具有十分重要的科学意义。文中针对几种主要陆地生态系统自然扰动（火灾、虫害、氮沉降、干旱和洪水等）分析扰动过程与陆地碳收支动态变化的关系,并在此基础上综述近年来相关研究的主要进展,总结生态系统扰动过程的主要研究方法和各自特点,重点介绍运用生态系统过程模型方法研究陆地生态系统对各种扰动过程的响应,分析当前相关研究中存在的主要问题和不确定性,最后对该领域的未来发展方向进行了展望。