CDM造林再造林项目源汇估计的不确定性源及其估算方法

从CDM造林、再造林项目人为净温室气体汇清除量估算值不确定性源的产生过程、各种不确定性源的不确定性分析以及量化不确定性的方法等方面论述与人为净温室气体汇清除不确定性有关的问题,提出量化人为净温室气体汇清除不确定性的方法和建议,以期对CDM-AR项目开发商选择合适的方法学以及确定未来改进方法学准确性的优先努力方向提供帮助。     

湖南省2010年 LUCF 温室气体排放清单编制研究

利用湖南省森林资源清查数据,运用生物量法,从森林和其它木质生物质生物量碳储量变化及森林转化碳排放两方面对省级 LUCF 温室气体排放清单编制进行研究。结果表明：湖南省2010年 LUCF 净吸收温室气体1720．54万 t CO2当量,其中森林和其它木质生物质生物量碳储量变化净吸收温室气体1764．54万 t CO2当量,森林转化净排放温室气体44．0万 t CO2当量;通过增加乔木林碳储量,相当于吸收 CO24195．64万 t 。湖南省2008年的特大冰灾导致2010年 LUCF 活动吸收温室气体量比2005年减少了30．93％。     

森林经营增汇减排计量研究——以思茅松林分为例

通过对清水河56号国有林进行小班区划,利用标准地调查获取思茅松林平均胸径、林分密度、林龄,采用思茅松林分密度控制模型和地位级指数,结合生物量扩展因子法,估量不同森林抚育强度下项目区思茅松的碳汇量。得出基线情景的碳汇量累计为5 0424.50 t CO_2-e,项目情景的碳汇量累计为63 961.69 t CO_2-e,是基线情景的1.3倍;项目净碳汇量为13 537.20 t CO_2-e,年均增汇减排量为676.86 t CO_2-e/年。结论表明,通过科学经营和人工抚育,选择合适的采伐量和采伐方式,是挖掘森林固碳潜力一种有效途径,运用林分密度控制模型和地位级指数,结合生物量扩展因子法,体现了不同森林经营模式下的林龄、立地条件和林分密度等因素的协同作用,为估量不同森林抚育强度下的碳汇量提供了有益示范。     

CDM林业碳汇项目的非持久性风险分析

对导致CDM林业碳汇项目人为净温室气体汇清除发生逆转的人为风险、自然风险以及碳逆转所带来的经济风险和环境风险进行分析,提出应对和减少这些风险的管理策略.     

基于温室气体自愿减排交易意愿的国有林场森林经营碳汇估算

以福建省罗源、连江两县的省属国有林场为研究对象,基于温室气体自愿减排交易法对其森林经营碳汇进行估算,结果表明,两县省属国有林场森林经营年均项目减排量为14340 t CO_(2)-e,第一监测期内实际减排量72742 t CO_(2)-e。     

重庆万州马尾松林经营碳汇项目计量研究

对重庆万州马尾松林经营碳汇项目进行计量研究的结果表明:项目期30年,基线情景下碳汇量累计为57 552 tC,项目情景下碳汇量累计为180 572 tC,是基线情景下的3.13倍;项目净碳汇量为123 020 tC,换算成CO2当量为451 074 tCO2-e,年均每hm2碳汇量为2.89 tCO2-e。通过森林经营可以有效增加碳储量,增强碳汇能力,对于建立碳汇效益补偿机制,完善碳汇交易市场,改善生态环境和应对区域气候变化有着重要意义。     

贵州省森林碳汇及潜力分析

区域层面的森林碳汇估算研究有利于为整体层面持续固碳增汇的森林经营提供科学参考,评估森林碳汇对减少区域内碳排放的贡献。采用温室气体清单估算法,对2000、2005和2010年贵州省森林碳汇进行估算,分别为1 538.0万t、2 244.7万t、2 431.4万t CO2当量,呈稳定增长趋势,占全省碳排放量的10.32%～14.47%。贵州省尚有161.70万hm2宜林地,如果能用于发展碳汇林业,每年可吸收CO2237.9万t,30年内将吸收CO2达7137.0万t。贵州省正处于碳排放增长阶段,相对于森林碳汇而言,本区域碳减排工作任重道远,森林碳汇能力有很大的提升空间。     

广州市城市森林生态系统碳汇功能研究

基于广州市2006年森林资源清查资料,结合实地测定数据,分析了广州市城市森林生态系统碳固定的生态功能.结果表明广州市各森林类型间CO2固定能力差异很大,变化范围为6.444 7～32.618 9 t·hm-2a-1;2005年广州市城市森林生态系统净固定CO2量为7 493 811 t,其中地上部分固定CO2量为6 391 232 t,土壤固定CO2量为1 102 579 t;在不同森林类型中,阔叶树固定CO2量最大,为4 216 106 t,占总净固定CO2量的56.30%,城区园林固定CO2量为974 010 t.占13%,针阔混交林固定CO2量为716 756 t,占9.6%,马尾松林固定CO2量为662 336 t,占8.8%,竹林固定CO2量为209 250 t,占2.8%,经济林固定CO2量为206 412 t,占2.7%,湿地松固定CO2量为170 973 t,占2.3%.针叶混交林固定CO2量为135 769 t,占1.8%,杉木林固定CO2量为115 368 t,占1.5%,灌丛疏林固定CO2量为86 831 t,占1.2%.     

基于LUCF变化的福建省林业碳汇潜力分析

土地利用变化和林业(LUCF)变化是观测林业碳汇变动的重要指南,林业碳汇潜力分析是实现碳中和的决策基础。选取福建省森林资源一类清查数据,采用2011年《省级温室气体清单编制指南》方法,在定量分析2013年及2018年福建省LUCF变化的基础上,探讨了福建省林业碳汇的提升潜力及方向。结果表明,福建省2013年森林生物量生长碳吸收总量为8023.73万tCO_(2)-e,乔木林固碳占总固碳量的90.89%,采伐消耗温室气体排放3598.37万tCO_(2)-e,占总排放量的83.64%。2018年相对2013年固碳量增长36.74%,采伐消耗温室气体排放减少4.50%。     

森林碳汇与区域环境保护

笔者以恩施州为例,运用生物量清单法估算森林碳汇量,运用数学模型估算CO2年排放量。计算出2015年恩施州森林碳汇量100.80万t,CO2年排放量237.61万t,净排放量136.41万t。得出按目前的经济发展速度和恩施州森林年增长量,在2015年CO2不会成为恩施州经济发展的制约因素。但从环境保护这方面出发,同时考虑发展以碳汇为目的的林业经济,恩施州应该加大对森林的管理力度,实行增汇减排措施,并对恩施州森林碳汇发展方向提出相关建议与措施。     

Greenhouse gas emissions between 1993 and 2002 from land-use change and forestry in Mexico

In this paper we present the Mexican inventory of greenhouse gas (GHG) emissions from the land-use sector. It involved integration of forest inventory, land-use and soil data in a GIS to estimate the net flux of GHG between 1993 and 2002.     

Elevated CO₂ enhances leaf senescence during extreme drought in a temperate forest

In 2007, an extreme drought and acute heat wave impacted ecosystems across the southeastern USA, including a 19-year-old Liquidambar styraciflua L. (sweetgum) tree plantation exposed to long-term elevated (E(CO(2))) or ambient (A(CO(2))) CO(2) treatments. Stem sap velocities were analyzed to assess plant response to potential interactions between CO(2) and these weather extremes. Canopy conductance and net carbon assimilation (A(net)) were modeled based on patterns of sap velocity to estimate indirect impacts of observed reductions in transpiration under E(CO(2)) on premature leaf senescence. Elevated CO(2) reduced sap flow by 28% during early summer, and by up to 45% late in the drought during record-setting temperatures. Modeled canopy conductance declined more rapidly in E(CO(2)) plots during this period, thereby directly reducing carbon gain at a greater rate than in A(CO(2)) plots. Indeed, pre-drought canopy A(net) was similar across treatment plots, but declined to ～40% less than A(net) in A(CO(2)) as the drought progressed, likely leading to negative net carbon balance. Consequently, premature leaf senescence and abscission increased rapidly during this period, and was 30% greater for E(CO(2)). While E(CO(2)) can reduce leaf-level water use under droughty conditions, acute drought may induce excessive stomatal closure that could offset benefits of E(CO(2)) to temperate forest species during extreme weather events.     

Decadal trends in net ecosystem production and net ecosystem carbon balance for a regional socioecological system

Carbon sequestration is increasingly recognized as an ecosystem service, and forest management has a large potential to alter regional carbon fluxes − notably by way of harvest removals and related impacts on net ecosystem production (NEP). In the Pacific Northwest region of the US, the implementation of the Northwest Forest Plan (NWFP) in 1993 established a regional socioecological system focused on forest management. The NWFP resulted in a large (82%) decrease in the rate of harvest removals on public forest land, thus significantly impacting the regional carbon balance. Here we use a combination of remote sensing and ecosystem modeling to examine the trends in NEP and net ecosystem carbon balance (NECB) in this region over the 1985-2007 period, with particular attention to land ownership since management now differs widely between public and private forestland. In the late 1980s, forestland in both ownership classes was subject to high rates of harvesting, and consequently the land was a carbon source (i.e. had a negative NECB). After the policy driven reduction in the harvest level, public forestland became a large carbon sink − driven in part by increasing NEP − whereas private forestland was close to carbon neutral. In the 2003-2007 period, the trend towards carbon accumulation on public lands continued despite a moderate increase in the extent of wildfire. The NWFP was originally implemented in the context of biodiversity conservation, but its consequences in terms of carbon sequestration are also of societal interest. Ultimately, management within the NWFP socioecological system will have to consider trade-offs among these and other ecosystem services.     

Country-level carbon balance of forest soils: a country-specific model based on case studies in Hungary

International agreements require countries to annually report on greenhouse gas emissions and removals. For the land-use sector, this includes estimating stock changes in various carbon pools. For carbon pools like mineral forest soil where a country-level statistical inventory based on measurements is very difficult, models are usually applied together with data from case studies. In this paper, we present a country-specific model together with case studies that aim at capturing major soil processes due to forestry activity. These processes include “hot moments”, e.g., disturbances that occur rarely but might result in relatively high emissions. The model only aims at developing a conservative estimate, rather than a central one, of net country-level carbon stock change with emissions overestimated and removals underestimated. The model is partially parameterised using paired sampling of soil organic carbon in the uppermost 30-cm layer, applying standard methods including those suggested by IPCC, in afforestations on former croplands and in artificial regenerations. Results show that soils of afforested croplands act as a sink, and carbon stock after regeneration might decrease due to disturbance by forest operations, but might also increase due to transfer of carbon from dead roots to soil depending on disturbance levels. The estimation at the country level, which involves additional considerations and data from the literature, suggests that overall, forest soils are a net sink in Hungary, but also that artificially limiting soil organic carbon changes estimation to the uppermost 30-cm layer as applied in the IPCC methodology might lead to artefacts.     

Seasonal CO(2) assimilation and stomatal limitations in a Pinus taeda canopy

Net CO(2) assimilation (A(net)) of canopy leaves is the principal process governing carbon storage from the atmosphere in forests, but it has rarely been measured over multiple seasons and multiple years. I measured midday A(net) in the upper canopy of maturing loblolly pine (Pinus taeda L.) trees in the piedmont region of the southeastern USA on 146 sunny days over 36 months. Concurrent data for leaf conductance and photosynthetic CO(2) response curves (A(net)-C(i) curves) were used to estimate the relative importance of stomatal limitations to CO(2) assimilation in the field. In fully expanded current-year and 1-year-old needles, midday light-saturated A(net) was constant over much of the growing season (5-6 &mgr;mol CO(2) m(-2) s(-1)), except during drought periods. During the winter season (November-March), midday A(net) of overwintering needles varied in proportion to leaf temperature. Net CO(2) assimilation at light saturation occurred when daytime air temperatures exceeded 5-6 degrees C, as happened on more than 90% of the sunny winter days. In both age classes of foliage, winter carbon assimilation accounted for approximately 15% of the daily carbon assimilation on sunny days throughout the year, and was relatively insensitive to year-to-year differences in temperature during this season. However, strong stomatal limitations to A(net) occurred as a result of water stress associated with freezing cycles in winter. During the growing season, drought-induced water stress produced the largest year-to-year differences in seasonal CO(2) assimilation on sunny days. Seasonal A(net) was more drought sensitive in current-year needles than in 1-year-old needles. Relative stomatal limitations to daily integrated A(net) were approximately 40% over the growing season, and summer drought rather than high temperatures had the largest impact on summer A(net) and integrated annual CO(2) uptake in the upper crown. Despite significant stomatal limitations, a long duration of near-peak A(net) in the upper crown, particularly in 1-year-old needles, conferred high seasonal and annual carbon gain.     

加拿大林业发展战略

文中首先对温室气体排放市场的形成和特征等做了简要的回顾和描述，并根据市场发展状况，将迄今为止的森林碳汇市场划分为3个阶段。然后，对阻碍森林碳汇市场的政策环境、买方和卖方的相关制约因素进行了讨论。最后，对森林碳汇市场的前景进行了展望。     

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.