Economic Assessment of Mitigation Options for Enhancing and Maintaining Carbon Sink Capacity in Indonesia

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.     

Forestry Mitigation Options for Mexico: Finding Synergies between National Sustainable Development Priorities and Global Concerns

We examine carbon (C) reference and mitigation scenarios for the Mexicanforest sector between the year 2000 and 2030. Estimates are presentedseparately for the period 2008–2012.Future C emissions and capture are estimated using a simulation modelthat: a) allocates the country land use/land cover classes among differentfuture uses and categories using demand-based scenarios for forestryproducts; b) estimates the total C densities associated to each land usecategory, and c) determines the net carbon implications of the process ofland use/cover change according to the different scenarios.The options analyzed include both afforestation/reforestation, such ascommercial, bionenergy and restoration plantations, and agroforestrysystems, and forest conservation, through the sustainable management ofnative forests and forest protection.The total mitigation potential, estimated as the difference between the totallong-term carbon stock in the reference and the mitigation scenario reaches300 × 10⁶ Mg C in the year 2012 and increases to 1,382 × 10⁶ Mg C in 2030. The average net sequestration in the 30 year period is 46 × 10⁶ Mg C yr^-1, or 12.5 × 10⁶ Mg C yr^-1 within the period 2008 to 2012. The costs of selected mitigation options range from 0.7–3.5 Mg C^-1 to 35 Mg C^-1. Some options are cost effective.     

Climate Change Mitigation Activities in the Philippine Forestry Sector: Application of the COMAP Model

The forest sector in the Philippines has the potential to be amajor sink for carbon (C). The present study was conducted to evaluatepotential forestry mitigation options in the Philippines using the Comprehensive Mitigation Assessment Process (COMAP)model. The baseline scenario (BAU) assumes that current trends continue upto the year 2030 (`business-as-usual'). Two mitigation scenarios wereevaluated: high scenario (HS) and low scenario (LS). The former ispatterned largely from the government's forest master plan while thelatter assumes a 50% lower success rate of the master plan.The results of the analyses show that by 2030, the total C stock of thePhilippine forest sector in the baseline scenario decreases to 814× 10⁶ Mg C,down by 37% compared to the 1990 level. The C stocks of the HS andLS mitigation scenarios were 22% and 18% higher than the BAU,respectively. Of the mitigation options assessed, long rotation plantationsand forest protection activities produce the greatest C gain (199 and 104× 10⁶ Mg, respectively under HS). The not present value (NPV)of benefits is highest in the bioenergyoption with $24.48 per Mg C (excluding opportunity costs) at a realdiscount rate of 12%. However, the investment and life cycle costs arealso highest using bioenergy.The study also estimated potential investments needed under the mitigationscenarios. The investment requirement for the LS amounts to $263× 10⁶ while for the HS it is $748 × 10⁶. Finally, policy issues anddecisions that may be useful for the Philippines to evaluate LULUCFmitigation options under the UNFCCC Kyoto Protocol, are identified anddiscussed.     

Mitigation Potential for Carbon Sequestration Through Forestry Activities in Southern and Eastern China

In this paper, forest protection, short- and long-rotation plantations, forestregeneration, agroforestry and other activities for carbon (C) sequestration wereevaluated. China may be divided into five sub-regions, of which three fallin the main forested areas of China, i.e., the northeast, the southeast andthe southwest regions. The forestry mitigation potential in these threeregions is the subject of this paper. The Comprehensive Mitigation AssessmentProcess (COMAP) model is used to calculatethe potential for carbon mitigation and the cost-effectiveness of eachmitigation option, assuming that 60 percent of the goals of long-termforestry plans of the Chinese government could be realized. The resultsshow that the total sequestered C by the mitigation scenario between2000 and 2030 for the three regions of China will be 2093 × 10⁶ Mg C, ofwhich 281 × 10⁶ Mg C will occur between 2008 and 2012. The total netbiomass sequestration (difference of mitigation and baseline scenarios) from2000 to 2030 and from 2008 to 2012 is 496 × 10⁶ Mg C and 59 × 10⁶ Mg Crespectively. The C sequestration potential could be higher if othertwo regions are included since the forest area of the two regions amount to26.5% of total forested area, in particular, the land area suitable forforestation in the northwest accounts for 45% of the total. The activitywith least investment cost per unit of C is forest regeneration, followedby long-rotation plantation and forest conservation. The mostinvestment-intensive activity is bioenergy. The total investment for all themitigation activities is US $12.7 billion. The above figures between2008–2012 provide an upper bound on the potential for early startprojects that might be eligible for the Clean Development Mechanism(CDM). The authors would like to note that the mitigation potential andcost-effectiveness of agroforestry and bioenergy projects need to be furtherstudied.     

Carbon mitigation potential and costs of forestry options in Brazil,China, India,Indonesia, Mexico,the Philippines and Tanzania

This paper summarizes studies of carbon (C) mitigation potential and costs of about 40 forestry options in seven developing countries. Each study uses the same methodological approach – Comprehensive Mitigation Assessment Process (COMAP) – to estimate the above parameters between 2000 and 2030. The approach requires the projection of baseline and mitigation land-use scenarios. Coupled with data on a per ha basis on C sequestration or avoidance, and costs and benefits, it allows the estimation of monetary benefit per Mg C, and the total costs and carbon potential. The results show that about half (3.0 Pg C) the cumulative mitigation potential of 6.2 Petagram (Pg) C between 2000 and 2030 in the seven countries (about 200× 10⁶ Mg C yr^-1) could be achieved at a negative cost and the remainder at costs ranging up to $100 Mg C^-1. About 5 Pg C could be achieved, at a cost less than $20 per Mg C. Negative cost potential indicates that non-carbon revenue is sufficient to offset direct costs of these options. The achievable potential is likely to be smaller, however, due to market, institutional, and sociocultural barriers that can delay or prevent the implementation of the analyzed options.     

Carbon storage and sequestration potential of selected tree species in India

A dynamic growth model (CO2FIX) was used for estimating the carbon sequestration potential of sal (Shorea Robusta Gaertn. f.), Eucalyptus (Eucalyptus Tereticornis Sm.), poplar (Populus Deltoides Marsh), and teak (Tectona Grandis Linn. f.) forests in India. The results indicate that long-term total carbon storage ranges from 101 to 156 Mg C?ha^?1, with the largest carbon stock in the living biomass of long rotation sal forests (82 Mg C?ha^?1). The net annual carbon sequestration rates were achieved for fast growing short rotation poplar (8 Mg C?ha^?1?yr^?1) and Eucalyptus (6 Mg C?ha^?1?yr^?1) plantations followed by moderate growing teak forests (2 Mg C?ha^?1?yr^?1) and slow growing long rotation sal forests (1 Mg C?ha^?1?yr^?1). Due to fast growth rate and adaptability to a range of environments, short rotation plantations, in addition to carbon storage rapidly produce biomass for energy and contribute to reduced greenhouse gas emissions. We also used the model to evaluate the effect of changing rotation length and thinning regime on carbon stocks of forest ecosystem (trees?+?soil) and wood products, respectively for sal and teak forests. The carbon stock in soil and products was less sensitive than carbon stock of trees to the change in rotation length. Extending rotation length from the recommended 120 to 150 years increased the average carbon stock of forest ecosystem (trees?+?soil) by 12%. The net primary productivity was highest (3.7 Mg ha^?1?yr^?1) when a 60-year rotation length was applied but decreased with increasing rotation length (e.g., 1.7 Mg ha^?1?yr^?1) at 150 years. Goal of maximum carbon storage and production of more valuable saw logs can be achieved from longer rotation lengths. ‘No thinning’ has the largest biomass, but from an economical perspective, there will be no wood available from thinning operations to replace fossil fuel for bioenergy and to the pulp industry and such patches have high risks of forest fires, insects etc. Extended rotation lengths and reduced thinning intensity could enhance the long-term capacity of forest ecosystems to sequester carbon. While accounting for effects of climate change, a combination of bioenergy and carbon sequestration will be best to mitigation of CO₂ emission in the long term.     

Forest land use change in the philippines and climate change mitigation

Tropical forests in countries like thePhilippines are important sources and sinks of carbon(C). The paper analyzes the contribution of Philippineforests in climate change mitigation. Since the 1500s,deforestation of 20.9 M ha (10⁶ ha) of Philippineforests contributed 3.7 Pg (10¹⁵ g) of C to theatmosphere of which 2.6 Pg were released this century. At present, forest land uses store 1091 Tg(10¹² g) of C and sequester 30.5 Tg C/yr whilereleasing 11.4 Tg C/yr through deforestation andharvesting. In the year 2015, it is expected that thetotal C storage will decline by 8% (1005 Tg) andtotal rate of C sequestration will increase by 17%(35.5 Tg/yr). This trend is due to the decline innatural forest area accompanied by an increase intree plantation area. We have shown that uncertaintyin national C estimates still exists because they arereadily affected by the source of biomass and Cdensity data. Philippine forests can act as C sink by:conserving existing C sinks, expanding C stocks, andsubstituting wood products for fossil fuels. Here weanalyze the possible implications of the provisions ofthe Kyoto Protocol to Philippine forests. Finally, wepresent current research and development efforts ontropical forests and climate change in the Philippinesto improve assessments of their role in the nations Cbudgets.     

Methodological issues in forestry mitigation projects: a case study of Kolar district

There is a need to assess climate change mitigation opportunities in forest sector in India in the context of methodological issues such as additionality, permanence, leakage and baseline development in formulating forestry mitigation projects. A case study of forestry mitigation project in semi-arid community grazing lands and farmlands in Kolar district of Karnataka, was undertaken with regard to baseline and project scenario development, estimation of carbon stock change in the project, leakage estimation and assessment of cost-effectiveness of mitigation projects. Further, the transaction costs to develop project, and environmental and socio-economic impact of mitigation project was assessed. The study shows the feasibility of establishing baselines and project C-stock changes. Since the area has low or insignificant biomass, leakage is not an issue. The overall mitigation potential in Kolar for a total area of 14,000 ha under various mitigation options is 278,380 t C at a rate of 20 t C/ha for the period 2005–2035, which is approximately 0.67 t C/ha/year inclusive of harvest regimes under short rotation and long rotation mitigation options. The transaction cost for baseline establishment is less than a rupee/t C and for project scenario development is about Rs. 1.5–3.75/t C. The project enhances biodiversity and the socio-economic impact is also significant.

Potential and Cost of Carbon Sequestration in the Tanzanian Forest Sector

The forest sector in Tanzania offers ample opportunities to reduce greenhouse gas emissions (GHG) and sequester carbon (C) in terrestrial ecosystems. More than 90% of the country's demand for primary energy is obtained from biomass mostly procured unsustainably from natural forests. This study examines the potential to sequester C through expansion of forest plantations aimed at reducing the dependence on natural forest for wood fuel production, as well as increase the country's output of industrial wood from plantations. These were compared ton conservationoptions in the tropical and miombo ecosystems. Three sequestrationoptions were analyzed, involving the establishment of short rotation and long rotation plantations on about 1.7 × 10⁶ hectares. The short rotation community forestry option has a potential to sequester an equilibrium amount of 197.4 × 10⁶ Mg C by 2024 at a net benefit of 79.5 × 10⁶, while yielding a NPV of 0.46 Mg^-1 C. The long rotation options for softwood and hardwood plantations will reach an equilibrium sequestration of 5.6 and 11.8 × 10⁶ Mg C at a negative NPV of 0.60 Mg^-1 C and 0.32 Mg^-1 C. The three options provide cost competitive opportunities for sequestering about 7.5 × 10⁶ Mg C yr^-1 while providing desired forest products and easing the pressure on the natural forests in Tanzania. The endowment costs of the sequestration options were all found to be cheaper than the emission avoidance cost for conservation options which had an average cost of 1.27 Mg^-1 C, rising to 7.5 Mg^-1 C under some assumptions on vulnerability to encroachment. The estimates shown here may represent the upper bound, because the actual potential will be influenced by market prices for inputs and forest products, land use policy constraints and the structure of global C transactions.     

A Framework for Monitoring and Evaluating Carbon Mitigation by Farm Forestry Projects: Example of a Demonstration Project in Chiapas,Mexico

Mitigation and Adaptation Strategies for Global Change - In Mexico an estimated 4.5 × 106ha are available for farm forestry, while up to 6.1 × 106 ha could be saved from deforestation by...     

Estimating soil carbon storage and mitigation under temperate coniferous forests in the southern region of Kashmir Himalayas

Soil physical and chemical properties were quantified to assess soil organic carbon (SOC) density (t ha^-1) and SOC CO2 mitigation (t ha^-1) under six forest strata Cedrus deodara (closed) (S1), Cedrus deodara (open) (S2), Abies pindrow-Picea smithiana (closed) (S3), Abies pindrow-Picea smithiana (open) (S4), Pinus wallichiana (closed) (S5) and Pinus wallichiana (open) (S6) in the southern region of Kashmir Himalayas India. Lowest average bulk density (D_b) of 0.95 was found same in S3 (σ?±?0.07) and S5 (σ?±?0.09) and highest D_b (1.08) was observed in S2 (σ?±?0.05). A relatively higher coarse fraction was observed in all the six strata ranging from 19.23 (SD?±?4.66) in S3 to 29.37 (σ?±?6.12) in S6. Soil pH ranged from 6.09 (σ?±?0.64) in S4 to 6.97 (σ?±?0.53) in S2. The region under biotic interference has observed significant deforestation and degradation in the past two decades leading to lower SOC% values compared to other studies in the adjoining regions of Indian Himalayas and temperate coniferous forests in general. SOC% values were observed to range from 1.03 (σ?±?0.22) in S2 to 2.25 (σ?±?0.23) in S3. SOC density ranged between 25.11 (σ?±?5.41) t ha^-1 in S2 and 51.93 (σ?±?5.24) t ha^-1 in S3. SOC CO2 mitigation density was found highest 190.59 (σ?±?19.23) t ha^-1 in S3 and lowest 92.16 (σ?±?19.86) t ha^-1 in S2. A significant variation was observed in SOC density within strata. SOC density values in closed strata in general exceed to those in open strata. Primary results indicate that the average SOC stock for all the strata is low due to continuous biotic pressure in the last two decades making it a potential region for SOC buildup under plus options of REDD + (Reducing emissions from deforestation and forest degradation) which includes conservation, sustainable management of forests and enhancement of forest carbon (C) stocks.     

Small holder’s carbon forestry project in Haryana India: issues and challenges

The small scale forestry carbon project in Haryana, India has been registered as a Clean Development Project (CDM) activity and is the first such projects from India. Developed under the Kyoto Protocol of United Nations Framework Convention on Climate Change (UNFCCC), the projects aims at restoring heavily degraded sandune affected private lands and contribute to climate change mitigation. The project is expected to sequester 234,584 tons of carbon dioxide (tCO²) in 20 years project cycle with an average annual sequestration of 11,729 (tCO²) per year. The project is expected to have a total carbon stock of 385,253.1 ton Carbon (tC) in the project life span of 20 years as against 7,920.6 (tC) in the baseline scenario. The carbon credits earned from the project is supposed to provide additional incentives to the smallholders who have formed a cooperative society for this purpose. This paper addresses the issues and challenges in developing the project activity and also discusses the lessons learned in the process. The project is supposed to help in poverty alleviation and has become a success story for rehabilitating degraded lands in semi arid regions of India through plantation forestry.     

天山北坡城市群碳储量时空变化及预测研究

为了有效评估城市群碳储量变化,以天山北坡城市群为研究对象,运用PLUS模型和InVEST模型,动态评估2000～2020年及2030年不同情景下土地利用变化及碳储量变化特征.结果表明,2000～2020年天山北坡城市群碳储量呈现持续增加趋势,且碳储量变化与土地利用变化密切相关,主要表现为2000～2010年林地面积的减少导致其碳储量减少约266×106t,2010～2020年草地面积的增加使其碳储量增加约69.14×10⁶t.2030年自然发展情景、生态保护情景和经济快速发展情景下碳储量预测值分别为8875.88×10⁶t、8895.58×10⁶t和8841.58×10⁶t;经济快速发展情景下碳储量最低,生态保护情景下碳储量最高.土地利用是影响碳储量空间变化分布的第一主导因素,贡献率接近于90%,土地利用强度与碳储量协调性分析与两者双变量空间自相关分析进一步验证了这一结论.土地利用变化在一定程度上能够对碳储量产生积极影响,对于本研究区而言,生态保护发展情景可能更符合未来城市发展模式,研究结果能够为土...     

长江流域农业区非点源氮的平衡变化及其区域性差异

建立长江流域农业区氮平衡变化模型,并在该模型的基础上,计算长江流域各县1990和2000年的氮平衡变化,然后汇总出全流域氮的输入、输出及剩余量. 计算结果显示,全流域农业区1990年氮的输入量为7.65×106 t/a,输出量为4.23×106 t/a,剩余量为3.42×106 t/a(其中进入水体2.05×106 t/a,残留在土壤中1.37×106 t/a);2000年全流域农业区氮的输入量为10.22×106 t/a,输出量为5.44×106 t/a,剩余量为4.78×106 t/a(其中进入水体2.65×106 t/a,残留在土壤中2.13×106 t/a);1990—2000年长江流域农业区氮输入量增加2.57×106 t/a,氮输出量增加1.21×106 t/a,剩余量增加1.36×106 t/a(其中进入水体氮变化量为0.60×106 t/a,残留在土壤中氮变化量为0.76×106 t/a). 重庆、上海、武汉、无锡、南昌、成都等地区氮进入水体的量变化较大,为今后长江流域农业区水体氮污染重点防治区.      

An assessment of carbon stock for various land use system in Aravally mountains, Western India

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.     

A macroeconomic analysis of adaptation to climate change impacts on forests in India

We examine the potential for adaptation to climate change in Indian forests, and derive the macroeconomic implications of forest impacts and adaptation in India. The study is conducted by integrating results from the dynamic global vegetation model IBIS and the computable general equilibrium model GRACE-IN, which estimates macroeconomic implications for six zones of India. By comparing a reference scenario without climate change with a climate impact scenario based on the IPCC A2-scenario, we find major variations in the pattern of change across zones. Biomass stock increases in all zones but the Central zone. The increase in biomass growth is smaller, and declines in one more zone, South zone, despite higher stock. In the four zones with increases in biomass growth, harvest increases by only approximately 1/3 of the change in biomass growth. This is due to two market effects of increased biomass growth. One is that an increase in biomass growth encourages more harvest given other things being equal. The other is that more harvest leads to higher supply of timber, which lowers market prices. As a result, also the rent on forested land decreases. The lower prices and rent discourage more harvest even though they may induce higher demand, which increases the pressure on harvest. In a less perfect world than the model describes these two effects may contribute to an increase in the risk of deforestation because of higher biomass growth. Furthermore, higher harvest demands more labor and capital input in the forestry sector. Given total supply of labor and capital, this increases the cost of production in all the other sectors, although very little indeed. Forestry dependent communities with declining biomass growth may, however, experience local unemployment as a result.     

Natural hydrocarbon emissions in the United Kingdom

Natural hydrocarbon emissions from both forests and agricultural lands have been estimated on a regional basis for the U.K. The results of this study suggest total emissions are significantly higher than is currently accepted, with the major forested areas of Scotland, Wales and the north of England dominating the area contributions. Non-methane hydrocarbons (NMHC) emitted from natural sources are estimated at 211 × 10³ tC yr⁻¹ which represents 13% of the total NMHC emissions in the U.K.     

Optimizing carbon sequestration in commercial forests by integrating carbon management objectives in wood supply modeling

This paper provides a methodology for generating forest management plans, which explicitly maximize carbon (C) sequestration at the forest-landscape level. This paper takes advantage of concepts first presented in a paper by Meng et al. (2003; Mitigation Adaptation Strategies Global Change 8:371–403) by integrating C-sequestration objective functions in existing wood supply models. Carbon-stock calculations performed in Woodstock^TM (RemSoft Inc.) are based on C yields generated from volume table data obtained from local Forest Development Survey plots and a series of wood volume-to-C content conversion factors specified in von Mirbach (2000). The approach is used to investigate the impact of three demonstration forest-management scenarios on the C budget in a 110,000 ha forest in south-central New Brunswick, Canada. Explicit demonstration scenarios addressed include (1) maximizing timber extraction either by clearcut or selection harvesting for greatest revenue generation, (2) maximizing total C storage in the forest landscape and in wood products generated from harvesting, and (3) maximizing C storage together with revenue generation. The level of clearcut harvesting was greatest for scenario 1 (≥15 × 10⁴ m³ of wood and ≥943 ha of land per harvesting period), and least for scenario 2 (=0 m³ per harvesting period) where selection harvesting dominated. Because softwood saw logs were worth more than pulpwood ($60 m⁻³ vs. $40 m⁻³) and were strategic to the long-term storage of C, the production of softwood saw logs exceeded the production of pulpwood in all scenarios. Selection harvesting was generally the preferred harvesting method across scenarios. Only in scenario 1 did levels of clearcut harvesting occasionally exceed those of selection harvesting, mainly in the removal of old, dilapidated stands early in the simulation (i.e., during periods 1 through 3). Scenario 2 provided the greatest total C-storage increase over 80 years (i.e., 14 × 10⁶ Mg C, or roughly 264 Mg ha⁻¹) at a cost of $111 per Mg C due to lost revenues. Scenarios 3 and 1 produced reduced storage rates of roughly 9 × 10⁶ Mg C and 3 × 10⁶ Mg C, respectively; about 64% and 22% of the total, 80-year C storage calculated in scenario 2. The bulk of the C in scenario 2 was stored in the forest, amounting to about 76% of the total C sequestered.     

Estimating net primary production and annual plant carbon inputs, and modelling future changes in soil carbon stocks in arable farmlands of northern Japan

Soil C sequestration in croplands is deemed to be one of the most promising greenhouse gas mitigation options for Japan's agriculture. In this context, changes in soil C stocks in northern Japan's arable farming area over the period of 1971-2010, specifically in the region's typical Andosol (volcanic ash-derived) and non-Andosol soils, were simulated using soil-type-specific versions of the Rothamsted carbon model (RothC). The models were then used to predict the effects, over the period of 2011-2050, of three potential management scenarios: (i) baseline: maintenance of present crop residue returns and green manure crops, as well as composted cattle manure C inputs (24-34 Mg ha⁻¹ yr⁻¹ applied on 3-55% of arable land according to crop), (ii) cattle manure: all arable fields receive 20 Mg ha⁻¹ yr⁻¹ of composted cattle manure, increased C inputs from crop residues and present C inputs from green manure are assumed, and (iii) minimum input: all above-ground crop residues removed, no green manure crop, no cattle manure applied. Above- and below-ground residue biomass C inputs contributed by 8 major crops, and oats employed as a green manure crop, were drawn from yield statistics recorded at the township level and crop-specific allometric relationships (e.g. ratio of above-ground residue biomass to harvested biomass on a dry weight basis). Estimated crop net primary production (NPP) ranged from 1.60 Mg C ha⁻¹ yr⁻¹ for adzuki bean to 8.75 Mg C ha⁻¹ yr⁻¹ for silage corn. For the whole region (143 × 10³ ha), overall NPP was estimated at 952 ± 60 Gg C yr⁻¹ (6.66 ± 0.42 Mg C ha⁻¹ yr⁻¹). Plant C inputs to the soil also varied widely amongst the crops, ranging from 0.50 Mg C ha⁻¹ yr⁻¹ for potato to 3.26 Mg C ha⁻¹ yr⁻¹ for winter wheat. Annual plant C inputs to the soil were estimated at 360 ± 45 Gg C yr⁻¹ (2.52 ± 0.32 Mg C ha⁻¹ yr⁻¹), representing 38% of the cropland NPP. The RothC simulations suggest that the region's soil C stock (0-30 cm horizon), across all soils, has decreased from 13.96 Tg C (107.5 Mg C ha⁻¹ yr⁻¹) in 1970 to 12.46 Tg C (96.0 Mg C ha⁻¹ yr⁻¹) in 2010. For the baseline, cattle manure and minimum input scenarios, soil C stocks of 12.13, 13.27 and 9.82 Tg C, respectively, were projected for 2050. Over the period of 2011-2050, compared to the baseline scenario, soil C was sequestered (+0.219 Mg C ha⁻¹ yr⁻¹) by enhanced cattle manure application, but was lost (−0.445 Mg C ha⁻¹ yr⁻¹) under the minimum input scenario. The effect of variations of input data (monthly mean temperature, monthly precipitation, plant C inputs and cattle manure C inputs) on the uncertainty of model outputs for each scenario was assessed using a Monte Carlo approach. Taking into account the uncertainty (standard deviation as % of the mean) for the model's outputs for 2050 (5.1-6.1%), it is clear that the minimum input scenario would lead to a rapid decrease in soil C stocks for arable farmlands in northern Japan.     

Full accounting of the greenhouse gas budget in the forestry of China

Forest management to increase carbon (C) sinks and reduce C emissions and forest resource utilization to store C and substitute for fossil fuel have been identified as attractive mitigation strategies. However, the greenhouse gas (GHG) budget of carbon pools and sinks in China are not fully understood, and the forestry net C sink must be determined. The objective of this study was to analyze potential forest management mitigation strategies by evaluating the GHG emissions from forest management and resource utilization and clarify the forestry net C sink, and its driving factors in China via constructing C accounting and net mitigation of forestry methodology. The results indicated that the GHG emissions under forest management and resource utilization were 17.7 Tg Ce/year and offset 8.5% of biomass and products C sink and GHG mitigation from substitution effects from 2000 to 2014, resulting in a net C sink of 189.8 Tg Ce/year. Forest resource utilization contributed the most to the national forestry GHG emissions, whereas the main driving factor underlying regional GHG emissions varied. Afforestation dominated the GHG emissions in the southwest and northwest, whereas resource utilization contributed the most to GHG emissions in the north, northeast, east, and south. Furthermore, decreased wood production, improved product use efficiency, and forests developed for bioenergy represented important mitigation strategies and should be targeted implementation in different regions. Our study provided a forestry C accounting in China and indicated that simulations of these activities could provide novel insights for mitigation strategies and have implications for forest management in other countries.