共查询到20条相似文献，搜索用时 31 毫秒
1.
Harris NL Brown S Hagen SC Saatchi SS Petrova S Salas W Hansen MC Potapov PV Lotsch A 《Science (New York, N.Y.)》2012,336(6088):1573-1576
Policies to reduce emissions from deforestation would benefit from clearly derived, spatially explicit, statistically bounded estimates of carbon emissions. Existing efforts derive carbon impacts of land-use change using broad assumptions, unreliable data, or both. We improve on this approach using satellite observations of gross forest cover loss and a map of forest carbon stocks to estimate gross carbon emissions across tropical regions between 2000 and 2005 as 0.81 petagram of carbon per year, with a 90% prediction interval of 0.57 to 1.22 petagrams of carbon per year. This estimate is 25 to 50% of recently published estimates. By systematically matching areas of forest loss with their carbon stocks before clearing, these results serve as a more accurate benchmark for monitoring global progress on reducing emissions from deforestation. 相似文献
2.
Managing forests for climate change mitigation 总被引：2，自引：0，他引：2
Forests currently absorb billions of tons of CO2 globally every year, an economic subsidy worth hundreds of billions of dollars if an equivalent sink had to be created in other ways. Concerns about the permanency of forest carbon stocks, difficulties in quantifying stock changes, and the threat of environmental and socioeconomic impacts of large-scale reforestation programs have limited the uptake of forestry activities in climate policies. With political will and the involvement of tropical regions, forests can contribute to climate change protection through carbon sequestration as well as offering economic, environmental, and sociocultural benefits. A key opportunity in tropical regions is the reduction of carbon emissions from deforestation and degradation. 相似文献
3.
毁林和森林退化不仅导致了生物多样性的大量丧失和生态系统服务能力的下降,而且已经成为全球第二大温室气体排放源。毁林和森林退化是实现联合国消除饥饿、减轻贫困和适应气候变化可持续发展目标的障碍。森林恢复是减缓(减少)毁林和森林退化的重要途径,与人类福祉息息相关,许多国家正独自或联合起来,持续地进行森林恢复活动。本研究从森林恢复的概念出发,探讨了森林恢复的目标和方式,分析了我国森林恢复存在的问题及应对措施,为学者、研究机构及政策部门等厘清森林恢复活动的脉络提供参考。 相似文献
4.
Balch JK Nepstad DC Brando PM Alencar A 《Science (New York, N.Y.)》2010,330(6011):1627; author reply 1627
Arag?o and Shimabukuro (Reports, 4 June 2010, p. 1275) reported that fires increase in agricultural frontiers even as deforestation decreases and concluded that these fires lead to unaccounted carbon emissions under the United Nations climate treaty's tropical deforestation and forest degradation component. Emissions from post-deforestation management activities are, in fact, included in these estimates--but burning of standing forests is not. 相似文献
5.
Land-use allocation protects the Peruvian Amazon 总被引：2，自引：0，他引：2
Oliveira PJ Asner GP Knapp DE Almeyda A Galván-Gildemeister R Keene S Raybin RF Smith RC 《Science (New York, N.Y.)》2007,317(5842):1233-1236
Disturbance and deforestation have profound ecological and socioeconomic effects on tropical forests, but their diffuse patterns are difficult to detect and quantify at regional scales. We expanded the Carnegie forest damage detection system to show that, between 1999 and 2005, disturbance and deforestation rates throughout the Peruvian Amazon averaged 632 square kilometers per year and 645 square kilometers per year, respectively. However, only 1 to 2% occurred within natural protected areas, indigenous territories contained only 11% of the forest disturbances and 9% of the deforestation, and recent forest concessions effectively protected against clear-cutting. Although the region shows recent increases in disturbance and deforestation rates and leakage into forests surrounding concession areas, land-use policy and remoteness are serving to protect the Peruvian Amazon. 相似文献
6.
Carbon pools and flux of global forest ecosystems 总被引：40，自引：0，他引：40
Dixon RK Solomon AM Brown S Houghton RA Trexier MC Wisniewski J 《Science (New York, N.Y.)》1994,263(5144):185-190
Forest systems cover more than 4.1 x 10(9) hectares of the Earth's land area. Globally, forest vegetation and soils contain about 1146 petagrams of carbon, with approximately 37 percent of this carbon in low-latitude forests, 14 percent in mid-latitudes, and 49 percent at high latitudes. Over two-thirds of the carbon in forest ecosystems is contained in soils and associated peat deposits. In 1990, deforestation in the low latitudes emitted 1.6 +/- 0.4 petagrams of carbon per year, whereas forest area expansion and growth in mid- and high-latitude forest sequestered 0.7 +/- 0.2 petagrams of carbon per year, for a net flux to the atmosphere of 0.9 +/- 0.4 petagrams of carbon per year. Slowing deforestation, combined with an increase in forestation and other management measures to improve forest ecosystem productivity, could conserve or sequester significant quantities of carbon. Future forest carbon cycling trends attributable to losses and regrowth associated with global climate and land-use change are uncertain. Model projections and some results suggest that forests could be carbon sinks or sources in the future. 相似文献
7.
Use of U.S. croplands for biofuels increases greenhouse gases through emissions from land-use change 总被引：3，自引：0，他引：3
Searchinger T Heimlich R Houghton RA Dong F Elobeid A Fabiosa J Tokgoz S Hayes D Yu TH 《Science (New York, N.Y.)》2008,319(5867):1238-1240
Most prior studies have found that substituting biofuels for gasoline will reduce greenhouse gases because biofuels sequester carbon through the growth of the feedstock. These analyses have failed to count the carbon emissions that occur as farmers worldwide respond to higher prices and convert forest and grassland to new cropland to replace the grain (or cropland) diverted to biofuels. By using a worldwide agricultural model to estimate emissions from land-use change, we found that corn-based ethanol, instead of producing a 20% savings, nearly doubles greenhouse emissions over 30 years and increases greenhouse gases for 167 years. Biofuels from switchgrass, if grown on U.S. corn lands, increase emissions by 50%. This result raises concerns about large biofuel mandates and highlights the value of using waste products. 相似文献
8.
Economic incentives for rain forest conservation across scales 总被引：1，自引：0，他引：1
Kremen C Niles JO Dalton MG Daily GC Ehrlich PR Fay JP Grewal D Guillery RP 《Science (New York, N.Y.)》2000,288(5472):1828-1832
Globally, tropical deforestation releases 20 to 30% of anthropogenic greenhouse gases. Conserving forests could reduce emissions, but the cost-effectiveness of this mechanism for mitigation depends on the associated opportunity costs. We estimated these costs from local, national, and global perspectives using a case study from Madagascar. Conservation generated significant benefits over logging and agriculture locally and globally. Nationally, however, financial benefits from industrial logging were larger than conservation benefits. Such differing economic signals across scales may exacerbate tropical deforestation. The Kyoto Protocol could potentially overcome this obstacle to conservation by creating markets for protection of tropical forests to mitigate climate change. 相似文献
9.
Chazdon RL 《Science (New York, N.Y.)》2008,320(5882):1458-1460
Despite continued forest conversion and degradation, forest cover is increasing in countries across the globe. New forests are regenerating on former agricultural land, and forest plantations are being established for commercial and restoration purposes. Plantations and restored forests can improve ecosystem services and enhance biodiversity conservation, but will not match the composition and structure of the original forest cover. Approaches to restoring forest ecosystems depend strongly on levels of forest and soil degradation, residual vegetation, and desired restoration outcomes. Opportunities abound to combine ambitious forest restoration and regeneration goals with sustainable rural livelihoods and community participation. New forests will require adaptive management as dynamic, resilient systems that can withstand stresses of climate change, habitat fragmentation, and other anthropogenic effects. 相似文献
10.
基于不同调查时点数据的黑龙江省土地利用变化及政策驱动分析 总被引：4，自引：1，他引：3
以土地调查数据为支撑,综合运用GIS空间叠加分析及土地利用双向动态度模型,分析黑龙江省土地利用变化特征与变化轨迹,探索土地政策对黑龙江省土地利用变化的驱动效应。结果显示,28 a来,黑龙江省土地利用发生了显著变化:耕地先减后增,其中林地、未利用地与草地对耕地增加贡献最大;林地呈现一定波动趋势,但总体面积基本持平;草地持续减少,主要转向耕地;建设用地快速增长,年均增长率为5.13%,远大于其他地类。耕地保护是土地利用变化的核心因素,直接推动其他各类用地变化;政策对土地利用变化的影响显著,建议在保障粮食安全的前提下,加大对草地与林地保护的政策支持。 相似文献
11.
基于福州市1995年、2005年和2015年3期Landsat影像解译数据以及地形和社会经济统计数据,利用Logistic-CA-Markov耦合模型探讨该地区土地利用变化及其与各驱动力因子之间的定量关系,并对福州市未来土地利用结构进行模拟预测。结果表明：（1）1995—2015年除建设用地持续增加外,其他4类用地均呈现减少趋势;建设用地的增加主要来源于林地和农地。（2）在Logistic回归分析中,林地转变主要受海拔高度因素影响,农地和水体转变主要受用地距离因素影响,建设用地和未利用土地主要受社会经济因素影响。（3）通过验证Logistic-CA-Markov模型具有较高的模拟精度。结果显示,2025年福州市建设用地和水体增加,林地、农地和未利用土地减少,其中1995—2025年建设用地增长速度最快,而未利用土地减少速度最快。 相似文献
12.
基于NbS的北京市乔木林固碳能力分析 总被引：1，自引：0，他引：1
[目的]乔木林生物质碳汇是影响森林碳汇的重要组成部分,是一种自然的气候解决方案,在全球气候变化大背景下,森林的固碳潜力一直被广泛关注,本文以北京市为例,分析不同的林业活动对乔木碳储量的影响.[方法]采用北京市森林资源设计调查数据,利用IPCC材积源-生物量法估算北京市乔木林碳储量,分析了2009-2014年北京市在森林... 相似文献
13.
基于GIS和RS的黄龙山林区土地时空动态变化分析 总被引：1，自引：0，他引：1
以黄龙山林区为研究对象,结合1990年、2000年、2008年3期TM图像,运用RS和GIS技术分析黄龙林区1990-2008年间土地利用动态的空间变化过程,并利用马尔柯夫模型对土地动态变化及演变趋势进行预测分析。结果表明:2000年以前,土地利用变化快,土地利用动态度为1.60%,并且转移较分散,而从2000年以后,土地利用动态度降为0.94%,转移方向趋于集中;1990-2008年期间,有林地面积增加最多,达427.06km2,疏林地和未利用地面积大幅减少,耕地面积先增后减,主要土地利用转变方式为其他土地利用类型转向有林地;预测结果表明:2008年以后的16a内(2008-2024年),研究区内耕地、疏林地、未利用地等将进一步减少且增减幅度不断降低;有林地和其他林地面积将继续增加,城乡用地和水域等也有增减但幅度不大。 相似文献
14.
Tropical deforestation and habitat fragmentation in the Amazon: satellite data from 1978 to 1988 总被引：2，自引：0，他引：2
Landsat satellite imagery covering the entire forested portion of the Brazilian Amazon Basin was used to measure, for 1978 and 1988, deforestation, fragmented forest, defined as areas less than 100 square kilometers surrounded by deforestation, and edge effects of 1 kilometer into forest from adjacent areas of deforestation. Tropical deforestation increased from 78,000 square kilometers in 1978 to 230,000 square kilometers in 1988 while tropical forest habitat, severely affected with respect to biological diversity, increased from 208,000 to 588,000 square kilometers. Although this rate of deforestation is lower than previous estimates, the effect on biological diversity is greater. 相似文献
15.
William D. Sunderlin 《Agriculture and Human Values》1997,14(4):373-386
Growth of the national cattle herd is contributing to rapid and inappropriate deforestation in Honduras. Field research was conducted in the Department of Olancho to better understand this problem and to assess the possibilities for local interest in forest protection. A recent upsurge in the profitability of cattle farming bodes badly for the forest, but three countervailing factors could ultimately serve as the basis for community-based forest management. First, area residents have a greater appreciation for the economic and ecological functions of the forest than one might surmise, given the rapid pace of deforestation. Second, timber is a significant source of community income, thus there may be latent incentives to maintain supplies in the long term. Third, some residents will not turn to cattle farming, in spite of its profitability, perhaps because of their dependence on timber marketing. Policies enacted in 1992 undermine theseincipient incentives for forest custodianship. Inappropriate deforestation can be lessened through policy reforms thatwould enable smallholders to conserve and manage their resources over the long-term. 相似文献
16.
王群超 《东北林业大学学报》2011,39(6):98-100
简述了国外基于固碳效益的最优轮伐期的研究.大量研究表明,当考虑人工林的固碳效益时,轮伐期长短会受影响,并会随碳价、贴现率变化而变化,并且这种变化通常很灵敏.通过总结国内关于森林固碳效益方面的研究,推导出固碳效益的一般模型,并将其引入到Faustmann最优轮伐期模型中,从而整理出基于固碳效益的最优轮伐期模型. 相似文献
17.
以无锡市2000、2005和2010年Landsat TM影像为数据源,采用决策树分类方法将无锡市土地利用类型分为建设用地、耕地、林地、园地和水域5大类。同时利用土地利用转移矩阵分析了2000～2010年无锡市土地利用特征。最后结合无锡市社会经济和人文数据,对无锡市土地利用变化的驱动力进行了分析。结果表明:2000～2010年无锡市各种土地利用类型总量和比例发生了巨大变化,城市建设用地面积不断扩大,耕地面不断减少,而园地和水域面积有小幅度的上升,林地基本维持在原来的比例,减少的耕地大部分转换为建设用地、水域和园地。人口的急剧增加和经济的快速发展是导致土地利用发生变化的2个重要原因。 相似文献
18.
抵御气候变化、遏制全球气候变暖是当今人类社会发展所面临的重大挑战之一。虽然当前国际碳市场存在诸多不确定因素,前景也十分不明朗,但随着世界各国的广泛参与,碳市场的参与主体将日趋多元化,碳交易体系也将日益成熟与完善。建议设定科学合理的减排指标,明确减排责任以确保我国碳市场的有效需求,同时通过建设符合实际、科学严格的计量和监测体系,营建林业碳汇的信息库和储备库等措施,将林业碳汇项目纳入到交易体系中,建立国内碳减排市场。 相似文献
19.
China's forest policy for the 21st century 总被引：1，自引：0，他引：1
Zhang P Shao G Zhao G Le Master DC Parker GR Dunning JB Li Q 《Science (New York, N.Y.)》2000,288(5474):2135-2136
A half-century policy of forest exploitation and monoculture in China has led to disastrous consequences, including degradation of forests and landscapes, loss of biodiversity, unacceptable levels of soil erosion, and catastrophic flooding. A new forest policy had been adopted in China called the Natural Forest conservation Program (NFCP), which emphasizes expansion of natural forests and increasing the productivity of forest plantations. Through locally focused management strategies, biodiversity and forest resources will be sustained, and downstream regions will be better protected from flooding. This new policy is being implemented with a new combination of policy tools, including technical training and education, land management planning, mandatory conversion of marginal farmlands to forest, resettlement and retaining of forest dwellers, share in private ownership, and expanded research. These policy tools may have wider relevance for other countries, particularly developing countries. 相似文献
20.
Forecasting fire season severity in South America using sea surface temperature anomalies 总被引：2，自引：0，他引：2
Chen Y Randerson JT Morton DC DeFries RS Collatz GJ Kasibhatla PS Giglio L Jin Y Marlier ME 《Science (New York, N.Y.)》2011,334(6057):787-791
Fires in South America cause forest degradation and contribute to carbon emissions associated with land use change. We investigated the relationship between year-to-year changes in fire activity in South America and sea surface temperatures. We found that the Oceanic Ni?o Index was correlated with interannual fire activity in the eastern Amazon, whereas the Atlantic Multidecadal Oscillation index was more closely linked with fires in the southern and southwestern Amazon. Combining these two climate indices, we developed an empirical model to forecast regional fire season severity with lead times of 3 to 5 months. Our approach may contribute to the development of an early warning system for anticipating the vulnerability of Amazon forests to fires, thus enabling more effective management with benefits for climate and air quality. 相似文献