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1.
Greenhouse gas emission has been scientifically shown to be the primary cause of observed global climate change. The reduction of greenhouse gas levels in the atmosphere deserves international attention. Aside from strategies to reduce emissions, increasing carbon (C) storage by forests has become an alternative method to lower carbon dioxide (CO2) levels. The present study assesses the potential of C storage to decrease gas emission by restoring cleared and disturbed spruce (picea) forests in the Qilian Mountains, northwestern China. We first introduced and tested a new method for live aboveground biomass (AGB) estimation. We then used the method to define the relationship of AGB with topographic wetness index (TWI) and precipitation seasonality for total AGB estimation and quantification of the realized C storage in the live AGB of existing spruce forests. The same strategies were adopted to estimate the total AGB and the related potential C storage in the projected potential spruce forest distribution. A species distribution model was used, and the results showed that the AGB of the Qinghai spruce forests ranged between 2.30 and 4.96 Mg per plot (0.021 ha), i.e., 110 Mg ha-1 to 236 Mg ha-1). Actual total AGB was measured at 33 Tg, and C storage was 17.3 Tg in existing spruce forests. Potential total AGB and potential C storage were greater if the cleared and the potential C storage was ~50 Tg.  相似文献   

2.
The carbon (C) sinks and sources of trees that may be accounted for under Article 3.3 of the Kyoto Protocol during the first commitment period from 2008 to 2012 were estimated for the countries of the European Union (EU) based on existing forest inventory data. Two sets of definitions for the accounted activities, afforestation, reforestation and deforestation, were applied. Applying the definitions by the Food and Agricultural Organization of the United Nations (FAO), the trees were estimated to be a C source in eight and a C sink in seven countries, and in the whole EU a C source of 5.4 Tg year−1. Applying the definitions by the Intergovernmental Panel of Climate Change (IPCC), the trees were estimated to be a C source in three and a C sink in 12 countries, and in the whole EU a C sink of 0.1 Tg year−1. These estimates are small compared with the C sink of trees in all EU forests, 63 Tg year−1, the anthropogenic CO2 emissions of the EU, 880 Tg C year−1, and the reduction target of the CO2 emissions, 8%. In individual countries, the estimated C sink of the trees accounted for under Article 3.3 was at largest 8% and the C source 12% compared with the CO2 emissions.  相似文献   

3.
Soil emission of CO2 is closely linked to soil degradation, decrease in soil organic carbon (SOC) content and decline in soil quality. Enhancing soil quality through adoption of best management practices (BMPs) and soil restoration can increase SOC content and soil productivity, and partially mitigate the greenhouse effect. The C sequestration potential through judicious management of world cropland includes 0.08–0.12 Pg/yr by erosion control, 0.02–0.03 Pg/yr by restoration of severely degraded soils, 0.02–0.04 Pg/yr by reclamation of salt-affected soils, 0.15–0.175 Pg/yr by adoption of conservation tillage and crop residue management, 0.18–0.24 Pg/yr by adoption of improved cropping system and 0.30–0.40 Pg/yr as C offset through biofuel production. The total C sequestration potential of the world cropland is about 0.75–1.0 Pg/yr or about 50% of annual emission of 1.6–1.8 Pg by deforestation and other agricultural activities. This finite soil-C sink could be filled over a 20 to 50-year period, during which energy related emission reductions gradually take effect at global scale. Improving soil quality is a win–win strategy, while increasing productivity it also improves environment and partially mitigates the greenhouse effect. Intensification of farming and increasing biomass production can lead to increased sequestration of C in soils, and to partly meet commitments under the Kyoto Protocol at national and global scales. Global reduction in C emission may have to be substantial if the atmospheric concentration of CO2 is to be stabilized at 550 ppmv. However, realization of this potential would require developing channels of communication between scientists and land managers and policy makers, and providing economic incentives.  相似文献   

4.
The 50% variation in the estimates of carbon (C) content in the forest soils of Russia at present is caused by confusion of terms and ignorance of the soil geographical representativeness in forests. The GIS-based analysis closes the gap to the estimate published earlier by Alexeyev and Birdsey (1994, p. 170). The average soil carbon density (SCD) for the 0.3 meter (m) layer of the forest soils in Russia is about 8.1 kg C m−2; the 1 m layer captures some 11.4 kg C m−2; and the 2 m layer holds nearly 12.3 kg C m− 2. The mass of C is about 61.6 Pg C concentrated in the 0.3 m layer of forest soils; the 1 m layer accumulates 87.6 Pg C and the 2 m layer holds about 94.1 Pg C. The C content in soils of the forest zone is much higher for Russia. The SCD is 18.8 kg C m− 2 and the soil C pool (SCP) is 223.6 Pg C in 1 m layer. Peat soils contribute a considerable portion of C to the forest zone of the country. The cold climate, permafrost and vegetation residues that are rich in recalcitrant compounds support a high accumulation rate of organic matter and associated nutrients in soils. This conservation is a mechanism to keep the production potential of the boreal ecosystems high in spite of their relatively low actual productivity in present environments.  相似文献   

5.
A sustainable forestry scenario aimed at meeting the projected biomassdemands, halting deforestation and regenerating degraded forests wasdeveloped and analyzed for additionality of mitigation and cost-effectivenessfor India. Similarly, mitigation potential of a commercial forestry scenarioaimed at meeting the biomass demands from forestry activities on privateland was assessed. India has a significant scale baseline scenario afforestationand effective forest conservation activities. India is afforesting at an averagegross rate of 1.55 × 106 ha yr-1 over the past 10 years, while the gross deforestation rate was 0.272 × 106 ha yr-1 during the same period. The sustainable forestry scenario could lead to an additional carbon (C) stock of 237 × 106 Mg C during 2000 to 2012, while the commercial forestry scenario apart from meeting all the incremental biomass demands (estimated for 2000 to 2015) could potentially lead to an additional carbon stock of 78 × 106Mg C during 2000 to 2012. Short- and Long-rotation forestry activities arecommercially viable. With appropriate policies and financial incentives allthe industrial wood, sawnwood and commercial fuelwood requirementcould be met through commercial forestry, so that government funds couldbe dedicated for conserving state owned forests and meeting subsistencebiomass demands. The commercial forestry activities could receive financialsupport under greenhouse gas (GHG) abatement programmes. The government, however, needs to develop institutions and guidelines to process, evaluate, approve and monitor forestry sector mitigation projects.  相似文献   

6.
土地利用/覆被变化(LUCC)对碳循环的影响研究已覆盖全球绝大多数地区,但中亚LUCC对森林生态系统碳库的影响仍属未知。论文以人工林面积、森林产品收获产量及林地转移面积为基础数据,应用Bookkeeping模型,分析了1975—2005年期间三种LUCC方式对中亚森林碳库的影响。近30 a LUCC对其碳库的影响总体表现为碳汇,固碳量为3.07 Tg。植树造林表现出强烈的碳汇功能,总固碳量为12.97 Tg。森林采伐是最主要的碳释放来源,共释放碳5.80 Tg。林地转移呈现较强的碳释放特征,共排放为4.10 Tg。结果表明1975—2005年该区域LUCC对森林碳库具有明显的增汇效应。研究结果将有利于减少LUCC对全球碳收支影响的不确定性。  相似文献   

7.
In Finland the percentage of biomass fuels of total primary energy supply is relatively high, close to 17%. The share of biomass in the total electricity generation is as much as 10%. This high share in Finland is mainly due to the cogeneration of electricity and heat within forest industry using biomass-based by-products and wastes as fuels. Forest industry is also a large user of fossil-based energy. About 28% of total primary energy consumption in Finland takes place in forest industry, causing about 16% of the total fossil carbon dioxide emissions.The Kyoto protocol limits the fossil CO2 and other greenhouse gas emissions and provides some incentives to the Finnish forest sector. There are trade-offs among the raw-material, energy and carbon sink uses of the forests. Fossil emissions can be reduced e.g. by using more wood and producing chemical pulp instead of mechanical one. According to the calculation rules of the Kyoto protocol Finnish forests in 2008–2012 are estimated to form a carbon source of 0.36 Tg C a−1 due to land use changes. Factually the forest biomass will still be a net carbon sink between 3.5 and 8.8 Tg C a−1. Because the carbon sinks of existing forests are not counted in the protocol, there is an incentive to increase wood use in those and to decrease the real net carbon sink. Also the criteria for sustainable forestry could still simultaneously be met.  相似文献   

8.

Forests are one of the most cost-effective ways to sequester carbon today. Here, I estimate the world’s land share under forests required to prevent dangerous climate change. For this, I combine newest longitudinal data of FLUXNET on forests’ net ecosystem exchange of carbon (NEE) from 78 forest sites (N?=?607) with countries’ mean temperature and forest area. This straightforward approach indicates that the world’s forests sequester 8.3 GtCO2year?1. For the 2 °C climate target, the current forest land share has to be doubled to 60.0% to sequester an additional 7.8 GtCO2year?1, which demands less red meat consumption. This afforestation/reforestation (AR) challenge is achievable, as the estimated global biophysical potential of AR is 8.0 GtCO2year?1 safeguarding food supply for 10 billion people. Climate-responsible countries have the highest AR potential. For effective climate policies, knowledge on the major drivers of forest area is crucial. Enhancing information here, I analyze forest land share data of 98 countries from 1990 to 2015 applying causal inference (N?=?2494). The results highlight that population growth, industrialization, and increasing temperature reduce forest land share, while more protected forest and economic growth generally increase it. In all, this study confirms the potential of AR for climate change mitigation with a straightforward approach based on the direct measurement of NEE. This might provide a more valid picture given the shortcomings of indirect carbon stock-based inventories. The analysis identifies future regional hotspots for the AR potential and informs the need for fast and forceful action to prevent dangerous climate change.

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9.
Due to large scale afforestation programs and forest conservation legislations, India’s total forest area seems to have stabilized or even increased. In spite of such efforts, forest fragmentation and degradation continues, with forests being subject to increased pressure due to anthropogenic factors. Such fragmentation and degradation is leading to the forest cover to change from very dense to moderately dense and open forest and 253 km2 of very dense forest has been converted to moderately dense forest, open forest, scrub and non-forest (during 2005–2007). Similarly, there has been a degradation of 4,120 km2 of moderately dense forest to open forest, scrub and non-forest resulting in a net loss of 936 km2 of moderately dense forest. Additionally, 4,335 km2 of open forest have degraded to scrub and non-forest. Coupled with pressure due to anthropogenic factors, climate change is likely to be an added stress on forests. Forest sector programs and policies are major factors that determine the status of forests and potentially resilience to projected impacts of climate change. An attempt is made to review the forest policies and programs and their implications for the status of forests and for vulnerability of forests to projected climate change. The study concludes that forest conservation and development policies and programs need to be oriented to incorporate climate change impacts, vulnerability and adaptation.  相似文献   

10.
Using an Integrated TerrestrialEcosystem C-budget model (InTEC), we simulated thecarbon (C) offset potentials of four alternativeforest management strategies in Canada: afforestation,reforestation, nitrogen (N) fertilization, andsubstitution of fossil fuel with wood, under differentclimatic and disturbance scenarios. C offset potentialis defined as additional C uptake by forest ecosystemsor reduced fossil C emissions when a strategy isimplemented to the theoretical maximum possibleextent. The simulations provided the followingestimated gains from management: (1) Afforesting allthe estimated 7.2 Mha of marginal agricultural landand urban areas in 1999 would create an average Coffset potential of 8 Tg C y-1 during 1999–2100,at a cost of 3.4 Tg fossil C emission in 1999. (2)Prompt reforestation of all forest lands disturbed inthe previous year during 1999–2100 would produce anaverage C offset potential of 57 Tg C y-1 forthis period, at a cost of 1.33 Tg C y-1. (3)Application of N fertilization (at the low rate of 5kg N ha-1 y-1) to the 125 Mha ofsemi-mature forest during 1999–2100 would create anaverage C offset of 58 Tg C y-1 for this period,at a cost of 0.24 Tg C y-1. (4) Increasingforest harvesting by 20% above current average ratesduring 1999–2100, and using the extra wood products tosubstitute for fossil energy would reduce averageemissions by 11 Tg C y-1, at a cost of 0.54 TgC y-1. If implemented to the maximum extent, thecombined C offset potential of all four strategieswould be 2–7 times the GHG emission reductionsprojected for the National Action Plan for ClimateChange (NAPCC) initiatives during 2000–2020, and anorder of magnitude larger than the projected increasein C uptake by Canada's agricultural soils due toimproved agricultural practices during 2000–2010.  相似文献   

11.
Net primary production (NPP) of terrestrial ecosystems provides food, fiber, construction materials, and energy to humans. Its demand is likely to increase substantially in this century due to rising population and biofuel uses. Assessing national forest NPP is of importance to best use forest resources in China. To date, most estimates of NPP are based on process-based ecosystem modeling, forestry inventory, and satellite observations. There are little efforts in using spatial statistical approaches while large datasets of in-situ observed NPP are available for Chinese forest ecosystems. Here we use the surveyed forest NPP and ecological data at 1,266 sites, the data of satellite forest coverage, and the information of climate and topography to estimate Chinese forest NPP and their associated uncertainties with two geospatial statistical approaches. We estimate that the Chinese forest and woodland ecosystems have total NPP of 1,325 ± 102 and 1,258 ± 186 Tg C year−1 in 1.57 million km2 forests with a regression method and a kriging method, respectively. These estimates are higher than the satellite-based estimate of 1,034 Tg C year−1 and almost double the estimate of 778 Tg C year−1 using a process-based terrestrial ecosystem model. Cross-validation suggests that the estimates with the kriging method are more accurate. Our developed geospatial statistical models could be alternative tools to provide national-level NPP estimates to better use Chinese forest resources.  相似文献   

12.
Carbon Management in Agricultural Soils   总被引:11,自引:0,他引:11  
World soils have been a major source of enrichment of atmospheric concentration of CO2 ever since the dawn of settled agriculture, about 10,000 years ago. Historic emission of soil C is estimated at 78 ± 12 Pg out of the total terrestrial emission of 136 ± 55 Pg, and post-industrial fossil fuel emission of 270 ± 30 Pg. Most soils in agricultural ecosystems have lost 50 to 75% of their antecedent soil C pool, with the magnitude of loss ranging from 30 to 60 Mg C/ha. The depletion of soil organic carbon (SOC) pool is exacerbated by soil drainage, plowing, removal of crop residue, biomass burning, subsistence or low-input agriculture, and soil degradation by erosion and other processes. The magnitude of soil C depletion is high in coarse-textured soils (e.g., sandy texture, excessive internal drainage, low activity clays and poor aggregation), prone to soil erosion and other degradative processes. Thus, most agricultural soils contain soil C pool below their ecological potential. Adoption of recommend management practices (e.g., no-till farming with crop residue mulch, incorporation of forages in the rotation cycle, maintaining a positive nutrient balance, use of manure and other biosolids), conversion of agriculturally marginal soils to a perennial land use, and restoration of degraded soils and wetlands can enhance the SOC pool. Cultivation of peatlands and harvesting of peatland moss must be strongly discouraged, and restoration of degraded soils and ecosystems encouraged especially in developing countries. The rate of SOC sequestration is 300 to 500 Kg C/ha/yr under intensive agricultural practices, and 0.8 to 1.0 Mg/ha/yr through restoration of wetlands. In soils with severe depletion of SOC pool, the rate of SOC sequestration with adoption of restorative measures which add a considerable amount of biomass to the soil, and irrigated farming may be 1.0 to 1.5 Mg/ha/yr. Principal mechanisms of soil C sequestration include aggregation, high humification rate of biosolids applied to soil, deep transfer into the sub-soil horizons, formation of secondary carbonates and leaching of bicarbonates into the ground water. The rate of formation of secondary carbonates may be 10 to 15 Kg/ha/yr, and the rate of leaching of bicarbonates with good quality irrigation water may be 0.25 to 1.0 Mg C/ha/yr. The global potential of soil C sequestration is 0.6 to 1.2 Pg C/yr which can off-set about 15% of the fossil fuel emissions.  相似文献   

13.
Land use, land-use change and forestry (LULUCF) projects may becomeeligible under Article 12 of the United Nations Framework Convention onClimate Change (UNFCCC) Kyoto Protocol's Clean DevelopmentMechanism (CDM). Some of the issues, which need to be addressed,include identifying the types of greenhouse gas (GHG) mitigation activitiesin LULUCF, which could be undertaken as CDM projects. Other issuesinvolve evaluating the mitigation potential and cost effectiveness of theactivities, as well as their likely socio-economic impacts and their influenceon the national carbon (C) stock. Three broad categories of mitigationactivities in LULUCF analyzed in this study include managing Cstorage, C conservation and carbon substitution. The C intensityof the activities was estimated to range from 37 to 218 Mg C per ha. The highest is in reforested land with slow growing species and the lowestin short-rotation plantations. At a real discount rate of 10%, investmentcosts required to implement the mitigation activities ranged from US$0.07 to 0.88 per Mg C, with life cycle costs ranging from US$ 0.07to 3.87 per Mg C, and benefits ranging from US$ –0.81 to 6.57 perMg C. Mitigation options with negative benefits are forest protection,reforestation, reduced impact logging and enhanced natural regeneration,while those with positive benefits are short rotation timber plantation, andbio-energy. Reforestation gave negative benefit since no revenue fromwood as trees are left in the forest for conservation, while Reduced ImpactLogging (RIL) and Enhanced Natural Regeneration (ENR)gave negative benefits because additional cost required to implement theoptions could not be compensated by the increase in round-hardwoodyield. Other factor is that the local price of round-hardwood is very low,i.e. US$ 160 per m3, while FOB price is between 250–400 US$ per m3. Total area available for implementing mitigationoptions (planting trees) in 1997 was 31 million hectares (× 106ha) (about 40% are critical lands, 35% grasslands and 25%unproductive lands).Total area being considered for implementing the options under baseline,government-plans and mitigation scenarios in the period 2000–2030 is12.6, 16.3 and 23.6 × 106 ha respectively. Furthermore, total area of production forest being considered for implementing reduced impactlogging and enrichment planting under the tree scenarios is 9, 26 and 16 × 106 ha respectively, and that for forest protection is 2.1, 3.7, 3.1× 106 ha respectively. The cumulative investment for implementingall mitigation activities in the three scenarios was estimated at 595, 892and 1026 million US$ respectively. National C stock under thebaseline scenario will continuously decline through 2030, while undergovernment-plans and mitigation scenarios the carbon stock increases. In2030, national C stock of the government and mitigation scenarios isalmost the same, 13% higher than that of baseline. However, the increasein national carbon stock in both scenarios could not offset carbon emissionsdue to deforestation.  相似文献   

14.
Carbon (C) conservation and sequestration in many developing countries needs to be accompanied by socio-economic improvements. Tree crop plantations can be a potential path for coupling climate change mitigation and economic development by providing C sequestration and supplying wood and non-wood products to meet domestic and international market requirements at the same time. Financial compensation for such plantations could potentially be covered by the Clean Development Mechanism under the United Nations Framework Convention on Climate Change (FCCC) Kyoto Protocol, but its suitability has also been suggested for integration into REDD?+?(reducing emissions from deforestation, forest degradation and enhancement of forest C stocks) currently being negotiated under the United Nations FCCC. We assess the aboveground C sequestration potential of four major plantation crops – cocoa (Theobroma cacao), oil palm (Elaeis guineensis), rubber (Hevea brasiliensis), and orange (Citrus sinesis) – cultivated in the tropics. Measurements were conducted in Ghana and allometric equations were applied to estimate biomass. The largest C potential was found in the rubber plantations (214 tC/ha). Cocoa (65 tC/ha) and orange (76 tC/ha) plantations have a much lower C content, and oil palm (45 tC/ha) has the lowest C potential, assuming that the yield is not used as biofuel. There is considerable C sequestration potential in plantations if they are established on land with modest C content such as degraded forest or agricultural land, and not on land with old-growth forest. We also show that simple C assessment methods can give reliable results, which makes it easier for developing countries to partake in REDD?+ or other payment schemes.  相似文献   

15.
Climate change is projected to impact forest ecosystems, including biodiversity and Net Primary Productivity (NPP). National level carbon forest sector mitigation potential estimates are available for India; however impacts of projected climate change are not included in the mitigation potential estimates. Change in NPP (in gC/m2/yr) is taken to represent the impacts of climate change. Long term impacts of climate change (2085) on the NPP of Indian forests are available; however no such regional estimates are available for short and medium terms. The present study based on GCM climatology scenarios projects the short, medium and long term impacts of climate change on forest ecosystems especially on NPP using BIOME4 vegetation model. We estimate that under A2 scenario by the year 2030 the NPP changes by (−5) to 40% across different agro-ecological zones (AEZ). By 2050 it increases by 15% to 59% and by 2070 it increases by 34 to 84%. However, under B2 scenario it increases only by 3 to 25%, 3.5 to 34% and (−2.5) to 38% respectively, in the same time periods. The cumulative mitigation potential is estimated to increase by up to 21% (by nearly 1 GtC) under A2 scenario between the years 2008 and 2108, whereas, under B2 the mitigation potential increases only by 14% (646 MtC). However, cumulative mitigation potential estimates obtained from IBIS—a dynamic global vegetation model suggest much smaller gains, where mitigation potential increases by only 6% and 5% during the period 2008 to 2108.  相似文献   

16.
Reducing carbon emissions from deforestation and degradation in developing countries is of the central importance in efforts to combat climate change. A study was conducted to measure carbon stocks in various land-use systems including forms and reliably estimates the impact of land use on carbon (C) stocks in the forest of Rajasthan, western India (23°3′–30°12′N longitude and 69°30′–78°17′E). 22.8% of India is forested and 0.04% is the deforestation rate of India. In Indian forest sector of western India of Aravally mountain range covered large area of deciduous forest and it’s very helpful in carbon sequestration at global level. The carbon stocks of forest, plantation (reforestation) and agricultural land in aboveground, soil organic and fine root within forest were estimated through field data collection. Results revealed that the amount of total carbon stock of forests (533.64?±?37.54 Mg·ha?1, simplified expression of Mg (carbon) ·ha?1) was significantly greater (P?<?0.05) than the plantation (324.37?±?15.0 Mg·ha?1) and the agricultural land (120.50?±?2.17 Mg·ha?1). Soil organic carbon in the forests (172.84?±?3.78 Mg·ha?1) was also significantly greater (P?<?0.05) than the plantation (153.20?±?7.48 Mg·ha?1) and the agricultural land (108.71?±?1.68 Mg·ha?1). The differences in carbon stocks across land-use types are the primary consequence of variations in the vegetation biomass and the soil organic matter. Fine root carbon was a small fraction of carbon stocks in all land-use types. Most of the soil organic carbon and fine root carbon content was found in the upper 30-cm layer and decreased with soil depth. The aboveground carbon (ABGC): soil organic carbon (SOC): fine root carbon ratios (FRC), was 8:4:1, 4:5:1, and 3:37:1 for the forest, plantation and agricultural land, respectively. These results indicate that a relatively large proportion of the C loss is due to forest conversion to agricultural land.  相似文献   

17.

Climate change is a global phenomenon that affects biophysical systems and human well-being. The Paris Agreement of the United Nations Framework Convention on Climate Change entered into force in 2016 with the objective of strengthening the global response to climate change by keeping global temperature rise this century well below 2 °C above pre-industrial levels and to pursue efforts to limit the temperature increase even further to 1.5 °C. The agreement requires all Parties to submit their “nationally determined contributions” (NDCs) and to strengthen these efforts in the years ahead. Reducing carbon emissions from deforestation and forest degradation is an important strategy for mitigating climate change, particularly in developing countries with large forests. Extensive tropical forest loss and degradation have increased awareness at the international level of the need to undertake large-scale ecological restoration, highlighting the need to identify cases in which restoration strategies can contribute to mitigation and adaptation. Here we consider Brazil as a case study to evaluate the benefits and challenges of implementing large-scale restoration programs in developing countries. The Brazilian NDC included the target of restoring and reforesting 12 million hectares of forests for multiple uses by 2030. Restoration of native vegetation is one of the foundations of sustainable rural development in Brazil and should consider multiple purposes, from biodiversity and ecosystem services conservation to social and economic development. However, ecological restoration still presents substantial challenges for tropical and mega-diverse countries, including the need to develop plans that are technically and financially feasible, as well as public policies and monitoring instruments that can assess effectiveness. The planning, execution, and monitoring of restoration efforts strongly depend on the context and the diagnosis of the area with respect to reference ecosystems (e.g., forests, savannas, grasslands, wetlands). In addition, poor integration of climate change policies at the national and subnational levels and with other sectorial policies constrains the large-scale implementation of restoration programs. The case of Brazil shows that slowing deforestation is possible; however, this analysis highlights the need for increased national commitment and international support for actions that require large-scale transformations of the forest sector regarding ecosystem restoration efforts. Scaling up the ambitions and actions of the Paris Agreement implies the need for a global framework that recognizes landscape restoration as a cost-effective nature-based solution and that supports countries in addressing their remaining needs, challenges, and barriers.

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18.
Using a map overlay procedure in a Geographical Information System environment, we quantify and map major land use and land cover (LULC) change patterns in Uganda period 1990–2005 and determine whether the transitions were random or systematic. The analysis reveals that the most dominant systematic land use change processes were deforestation (woodland to subsistence farmland—3.32%); forest degradation (woodland to bushland (4.01%) and grassland (4.08%) and bush/grassland conversion to cropland (5.5%) all resulting in a net reduction in forests (6.1%). Applying an inductive approach based on logistic regression and trend analyses of observed changes we analyzed key drivers of LULC change. Significant predictors of forest land use change included protection status, market access, poverty, slope, soil quality and presence/absence of a stream network. Market access, poverty and population all decreased the log odds of retaining forests. In addition, poverty also increased the likelihood of degradation. An increase in slope decreased the likelihood of deforestation. Using the stock change and gain/loss approaches we estimated the change in forest carbon stocks and emissions from deforestation and forest degradation. Results indicate a negligible increase in forest carbon stocks (3,260 t C yr-1) in the period 1990–2005 when compared to the emissions due to deforestation and forest degradation (2.67 million t C yr-1). In light of the dominant forest land use change patterns, the drivers and change in carbon stocks, we discuss options which could be pursued to implement a future national REDD plus strategy which considers livelihood, biodiversity and climate change mitigation objectives.  相似文献   

19.
Despite the economic and environmental significance of the world’s forests, we have limited data about them. Estimates of deforestation in tropical countries and rates of reforestation or afforestation in boreal and temperate countries are inconsistent. Accordingly, estimates of emissions released in deforestation vary widely and range from 7% to 17% of all sources of greenhouse gas (GHG) emissions. The lack of good data severely hampers efforts to shape climate policy because it is difficult to model the role of forests both in the physical global carbon (C) cycle and in cost-effective regimes to abate GHG. Data limits strain the capacity of even the best models to estimate marginal cost functions for forest carbon (C) sequestration. It is technically possible to obtain better information, but for institutional and economic reasons these technologies have not yet been fully deployed. The emergence of carbon (C) trading or tax policy in which forest carbon (C) storage becomes valued would strengthen incentives to supply better data, as would nonmarket regulation if it elicited a shadow value of forest carbon (C) in substituting for reductions in greenhouse gas emissions. “Geo-wiki” may provide a short-term solution to at least part of the data problem. The ultimate solution is the development of a comprehensive forest monitoring system involving remote sensing and on-the-ground truthing. This paper briefly discusses the role of forests in climate policy and then describes data gaps, the capability of technology to fill them, the limits of institutions and budgets in realizing this capability, and possible near-term solutions.  相似文献   

20.
Forests have the potential to be a sink in the global carbon (C) budget and thus play an important role in mitigating climate change. However, large-scale management of forests to their sink potential requires understanding of factors responsible for changes in forest C stocks. In this paper, we quantify the effects of initial forest landscape condition and disturbance rates on landscape-level changes in forest C stocks using predictions for managed forests in Ontario, Canada. Ten-year changes in C stocks in public forests managed for wood fibre production were simulated under four scenarios reflecting the range of volume harvested between 1998 and 2007. Changes in forest C stocks varied across Ontario and with harvest rate, resulting in the forest ranging from being a source of 0.767 tC ha-1 year?1 to a sink of 0.656 tC ha?1 year?1. Simulation results were used to develop a predictive equation explaining over 93 % of the variation in forest C stocks. Variables included in the equation, in descending order of their effect on changes in forest C stocks, were relative harvest rate, forest growth rate, natural disturbance rate, and initial forest C stocks. A reduced equation, including only the first three variables, explained nearly 89 % of the variation in forest C stocks. The results indicate that short-term changes in C stocks depend on initial forest condition and that there are limits to how much these changes can be manipulated by altering harvest and disturbance rates.  相似文献   

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