吉林省森林植被固碳现状与速率

通过对吉林省森林植被的普遍调查、典型调查以及植被样品含碳率测定, 结合吉林省2009年和2014年森林清查数据, 估算了区域森林植被的碳储量、碳密度及固碳速率。研究结果表明: 林下植被的生物量在不同林分和同类林分中存在较大的差异, 整体不足乔木层生物量的3%, 灌木植物的生物量略高于草本植物和幼树。不同林分类型的乔木含碳率介于45.80%-52.97%之间, 整体表现为针叶林高于阔叶林; 灌木和草本植物分别为39.79%-47.25%和40%左右。吉林省森林植被碳转换系数以0.47或0.48更为准确, 若以0.50或0.45作为植被的碳转换系数计算碳储量, 会造成±5.26%的偏差。吉林省森林植被不仅维持着较高的碳库水平, 而且极具碳汇能力; 2009年和2014年碳储量分别为471.29 Tg C和505.76 Tg C, 累计碳增量34.47 Tg C, 平均每年碳增量6.89 Tg C·a^-1; 碳密度由64.58 t·hm^-2增至66.68 t·hm^-2, 平均增加2.10 t·hm^-2, 固碳速率0.92 t·hm^-2·a^-1。森林植被碳储量的增长主体是蒙古栎(Quercus mongolica)林和阔叶混交林, 合计碳增量占总体的90.34%。受植被发育引起的生物量增长、林分龄组晋级以及森林经营所引起的面积变化影响, 各龄组植被碳增量为幼龄林>过熟林>近熟林>中龄林, 成熟林表现为负增长; 固碳速率为过熟林>幼龄林>近熟林>中龄林>成熟林。森林植被碳储量和碳密度的市/区分布整体表现为自东向西明显的降低变化; 碳增量以东北和中东部地区较高, 西部地区较低; 固碳速率整体以南部的通化地区和白山地区相对较高, 中部的吉林地区和东部的延边地区次之, 西部的白城地区、松原地区等地呈负增长。     

Current stocks and rate of sequestration of forest carbon in Gansu Province,China

Aims
Carbon sequestration is the basic function and most primary service of forest ecosystems, and plays a vital role in mitigating the global climate change. However, carbon storage and allocation in forest ecosystems have been less studied at regional scales than at forest stand levels, and the results are subject to uncertainty due to inconsistent methodologies. In this study we aim to obtain relatively accurate estimates of forest carbon stocks and sequestration rate at a provincial scale (regional) based on plot surveys of plants and soils.
Methods
In consideration of the areas and distributions of major forest types, 212 sampling plots, covering different age classes and origins (natural forests vs. planted forests), were surveyed in Gansu Province in northern China. Field investigations were conducted for vegetation layers (trees, shrubs, herbs and litter), soil profiles, and sampling of both plant materials and soils for laboratory analyses. Regional carbon stocks were calculated by up-scaling the carbon densities of all forest types with their corresponding areas. Carbon sequestration rate was estimated by referencing the reports of national forest inventory data for different periods.
Important findings Forest carbon stocks at the provincial scale were estimated at 612.43 Tg C, including 179.04 Tg C in biomass and 433.39 Tg C in soil organic materials. Specifically, natural forests stored 501.42 Tg C, approximately 4.52 times than that of the plantations. Biomass carbon density in both natural forests and plantations showed an increasing trend with stand age classes, and was greater in natural forests than in plantations within the same age classes. Soil carbon density also increased with stand age classes in natural forests, but the highest value occurred at the pre-mature stage in plantations. The weighted average of regional biomass carbon density was at 72.43 Mg C·hm^-2, with the average value of 90.52 Mg C·hm^-2 in natural forests and 33.79 Mg C·hm^-2 in plantations, respectively. In 1996, vegetation stored 132.47 Tg C in natural forests and 12.81 Tg C in plantations, respectively, and the values increased to 152.41 and 26.63 Tg C in 2011, with the mean carbon sequestration rates of 1.33 and 0.92 Tg C·a^-1. Given that young and middle-aged forests account for a large proportion (62.28%) of the total forest areas, the region is expected to have substantial potential of carbon sequestration.     

Current forest carbon stocks and carbon sequestration potential in Anhui Province,China

Aims
This study was conducted to investigate carbon stocks in forest ecosystems of different stand ages in Anhui Province, and to identify the carbon sequestration potential of climax forests controlled by the natural environment conditions.
Methods
Data were collected based on field investigations and simulations were made with the BIOME4 carbon cycle model.
Important findings
Currently, the total forest carbon stocks in Anhui Province amounts to 714.5 Tg C: 402.1 Tg C in vegetation and 312.4 Tg C in soil. Generally, both the total and vegetation carbon density exhibit an increasing trend with the natural growth of forest stands. Soil carbon density increases from young to near mature forests, and then gradually decreases thereafter. Young and middle-aged forests account for 75% of the total forest area in Anhui Province, with potentially an additional 125.4 Tg C to be gained after the young and middle-aged forests reach near mature stage. Results of BIOME4 simulations show that potentially an additional 245.7 Tg C, including 153.7 Tg C in vegetation and 92 Tg C in soil, could be gained if the current forests are transformed into climax forest ecosystems in Anhui Province.     

甘肃省森林碳储量现状与固碳速率

针对森林碳平衡再评估的重要性和区域尺度森林生态系统碳库量化分配的不确定性, 该研究依据全国森林资源连续清查结果中甘肃省各森林类型分布的面积与蓄积比重以及林龄和起源等要素, 在甘肃省布设212个样地, 经野外调查与采样、室内分析, 并对典型样地信息按照面积权重进行尺度扩展, 估算了甘肃省森林生态系统碳储量及其分布特征。结果表明: 甘肃省森林生态系统总碳储量为612.43 Tg C, 其中植被生物量碳为179.04 Tg C, 土壤碳为433.39 Tg C。天然林是甘肃省碳储量的主要贡献者, 其值为501.42 Tg C, 是人工林的4.52倍。天然林和人工林的植被碳密度均表现为随林龄的增加而增加的趋势, 同一龄组天然林植被碳密度高于人工林。天然林土壤碳密度从幼龄林到过熟林逐渐增加, 但人工林土壤碳密度最大值主要为近熟林。全省森林植被碳密度均值为72.43 Mg C·hm^-2, 天然林和人工林分别为90.52和33.79 Mg C·hm^-2。基于森林清查资料和标准样地实测数据, 估算出全省天然林和人工林在1996年的植被碳储量为132.47和12.81 Tg C, 2011年分别为152.41和26.63 Tg C, 平均固碳速率分别为1.33和0.92 Tg C·a^-1。甘肃省幼、中龄林面积比重较大, 占全省的62.28%, 根据碳密度随林龄的动态变化特征, 预测这些低龄林将发挥巨大的碳汇潜力。     

Current stocks and potential of carbon sequestration of the forest tree layer in Qinghai Province,China

为阐明青海省森林生态系统乔木层植被碳储量现状及其分布特征, 该研究利用240个标准样地实测的乔木数据, 估算出青海省森林生态系统不同林型处于不同龄级阶段的平均碳密度, 并结合青海省森林资源清查资料所提供的不同龄级的各林型面积, 估算了青海省森林生态系统乔木层的固碳现状、速率和潜力。结果表明: 1) 2011年青海省森林乔木层平均碳密度为76.54 Mg·hm ^-2, 总碳储量为27.38 Tg。云杉(Picea spp.)林、柏木(Cupressus funebris)林、桦木(Betula spp.)林、杨树(Populus spp.)林是青海地区的主要林型, 占青海省森林面积的96.23%, 占青海省乔木层碳储量的86.67%, 其中云杉林的碳储量(14.78 Tg)和碳密度(106.93 Mg·hm ^-2)最高。按龄级划分, 乔木层碳储量表现为过熟林>中龄林>成熟林>近熟林>幼龄林。2)青海省乔木层总碳储量从2003年的23.30 Tg增加到2011年的27.38 Tg, 年平均碳增量为0.51 Tg·a ^-1。乔木层固碳速率为1.06 Mg·hm ^-2·a ^-1, 其中柏木林的固碳速率最大(0.44 Mg·hm ^-2·a ^-1); 桦木林的固碳速率为负值(-1.06 Mg·hm ^-2·a ^-1)。3)青海省乔木层植被固碳潜力为8.50 Tg, 其中云杉林固碳潜力最高(3.40 Tg)。该研究结果表明青海省乔木层具有较大的固碳潜力, 若对现有森林资源进行合理管理和利用, 将会增加青海省森林的碳固存能力。     

安徽省森林碳储量现状及固碳潜力

为阐明安徽省不同林龄的森林生态系统的碳储量现状, 以及现有自然环境条件下顶极森林生态系统的固碳潜力, 采用野外样地调查和BIOME4模型方法对此进行研究。安徽省森林生态系统的现状总碳储量为714.5 Tg C, 其中植被碳402.1 Tg C、土壤碳312.4 Tg C。从幼龄林至过熟林的生长过程中, 森林生态系统的总碳密度和植被碳密度都呈现增长趋势。但土壤碳密度从幼龄林至近熟林阶段呈增加趋势, 近熟林以后出现减少趋势。安徽省幼龄林和中龄林占森林总面积的75%, 若幼、中龄林发展到近熟林阶段, 将增加125.4 Tg C。BIOME4模拟显示: 当森林发展到气候顶极森林时, 安徽省森林生态系统将增加245.7 Tg C, 即总固碳潜力包括植被固碳153.7 Tg C, 土壤固碳92.0 Tg C。     

Carbon storage and its distribution of forest ecosystems in Zhejiang Province,China

Aims
The concentration of CO₂ and other greenhouse gases in the atmosphere has considerably increased over last century and is set to rise further. Forest ecosystems play a key role in reducing CO₂ concentration in the atmosphere and mitigating global climate change. Our objective is to understand carbon storage and its distribution in forest ecosystems in Zhejiang Province, China.
Methods
By using the 8th forest resource inventory data and 2011-2012 field investigation data, we estimated carbon storage, density and its distribution in forest ecosystems of Zhejiang Province.
Important findings
The carbon storage of forest ecosystems in Zhejiang Province was 602.73 Tg, of which 122.88 Tg in tree layer, 16.73 Tg in shrub-herb layer, 11.36 Tg in litter layer and 451.76 Tg in soil layer accounting for 20.39%, 2.78%, 1.88% and 74.95% of the total carbon storage, respectively. The carbon storage of mixed broadleaved forests was 138.03 Tg which ranked the largest (22.90%) among all forest types. The young and middle aged forests which accounted for 70.66% of the total carbon storage were the main body of carbon storage in Zhejiang Province. The carbon density of forest ecosystems in Zhejiang Province was 120.80 t·hm^-2 and that in tree layer, shrub-herb layer, litter layer and soil layer were 24.65 t·hm^-2, 3.36 t·hm^-2, 2.28 t·hm^-2 and 90.51 t·hm^-2, respectively. The significant relationship between soil organic carbon storage and forest ecosystem carbon storage indicated that soil carbon played an important role in shaping forest ecosystem carbon density. Carbon density of tree layer increased with age in natural forests, but decreased in the order over-mature > near-mature > mature > middle-aged > young forest in plantations. The proportions of young and middle aged forests were larger than any other age classes. Thereby, the carbon storage of forest ecosystems in Zhejiang Province could be increased through a proper forest management.     

四川省森林植被固碳经济价值动态

<正>确估算森林植被固碳经济价值可为森林生态系统的生态效益评价提供基础数据。利用1997年和2014年两期四川省森林资源清查数据,依据不同森林类型的生物量与蓄积量回归方程和支付意愿法,估算了四川省两个时期森林植被的固碳经济价值。结果表明,从1997年到2014年,四川省森林植被固碳经济价值由703.17亿元增长到865.75亿元,净增长162.58亿元,年均增长9.56亿元,年均增长率为1.36%;在两个时期,云冷杉林的固碳经济价值比重最大,分别占总固碳经济价值的54.82%和46.62%,表明云冷杉森林植被类型在全省森林植被固碳经济价值中占有重要的地位;四川省天然林和人工林植被的固碳经济价值均呈增加趋势,并且人工林植被固碳经济价值年均增长速率(7.42%)明显高于天然林(1.03%);四川省森林植被固碳经济价值总体上随林龄的增加而增加。研究结果说明,实施包括天然林保护工程在内的森林保护和经营管理措施对提高森林植被的固碳经济价值具有重要的作用。     

Soil carbon storage and its determinants in the forests of Shaanxi Province,China

Aims The bank of soil carbon of forests plays an important role in the global carbon cycle. Our aim is to understand the characteristics of soil carbon storage and its determinants in the forests in Shaanxi Province.Methods The data of forest inventory in 2009 and resampling in 2011 were used to analyze the characteristics of soil carbon storage and its determinants in the forest soil in Shaanxi Province.Important findings The soil carbon storage in the forests in Shaanxi Province was 579.68 Tg. Soil carbon storage of Softwood and Hardwood forests were the highest among all forest types, accounting for 36.35% of the whole province forest soil carbon storage. The forest soil carbon storage was 4.15 times greater in the natural forest (467.17 Tg) than that in the plantations. The young and middle-aged forests were the main contributors to the total carbon storage across all age groups, accounting for about 57.30% of the total forest soil carbon storage. The average soil carbon density of forests in Shaanxi Province was 90.68 t∙hm^-2, in which the soil carbon density of Betula forests was the highest (141.74 t∙hm^-2). Soil carbon density of different forest types were gradually decreased with soil depth. In addition, it was highest in middle-aged forest. Soil carbon density was higher in the natural forest ecosystems than that in the plantations within the each age group, indicating natural forest ecosystems have higher capacity of carbon sequestration. Differences in the spatial patterns between carbon storage and density indicated that carbon storage was related to forest coverage. The soil carbon density and storage of forests in Yulin were the lowest across the province. This suggests that, in order to enhance the regional carbon sequestration capacity in this region, we need to appropriately strengthen artificial afforestation activities and manage them scientifically and rationally. The soil carbon density of forests in Shaanxi Province decreased with the increase of longitude, latitude, and annual temperature, but increased with the increase of altitude and annual rainfall. This study provides data basis for provincial estimation of forest soil carbon bank in China.     

青海省森林乔木层碳储量现状及固碳潜力

为阐明青海省森林生态系统乔木层植被碳储量现状及其分布特征, 该研究利用240个标准样地实测的乔木数据, 估算出青海省森林生态系统不同林型处于不同龄级阶段的平均碳密度, 并结合青海省森林资源清查资料所提供的不同龄级的各林型面积, 估算了青海省森林生态系统乔木层的固碳现状、速率和潜力。结果表明: 1) 2011年青海省森林乔木层平均碳密度为76.54 Mg·hm ^-2, 总碳储量为27.38 Tg。云杉(Picea spp.)林、柏木(Cupressus funebris)林、桦木(Betula spp.)林、杨树(Populus spp.)林是青海地区的主要林型, 占青海省森林面积的96.23%, 占青海省乔木层碳储量的86.67%, 其中云杉林的碳储量(14.78 Tg)和碳密度(106.93 Mg·hm ^-2)最高。按龄级划分, 乔木层碳储量表现为过熟林>中龄林>成熟林>近熟林>幼龄林。2)青海省乔木层总碳储量从2003年的23.30 Tg增加到2011年的27.38 Tg, 年平均碳增量为0.51 Tg·a ^-1。乔木层固碳速率为1.06 Mg·hm ^-2·a ^-1, 其中柏木林的固碳速率最大(0.44 Mg·hm ^-2·a ^-1); 桦木林的固碳速率为负值(-1.06 Mg·hm ^-2·a ^-1)。3)青海省乔木层植被固碳潜力为8.50 Tg, 其中云杉林固碳潜力最高(3.40 Tg)。该研究结果表明青海省乔木层具有较大的固碳潜力, 若对现有森林资源进行合理管理和利用, 将会增加青海省森林的碳固存能力。     

Carbon storage and potentials of the broad-leaved forest in alpine region of the Qinghai- Xizang Plateau,China

Aims
Our objective was to explore the vegetation carbon storages and their variations in the broad-leaved forests in the alpine region of the Qinghai-Xizang Plateau that includes Qinghai Province and Xizang Autonomous Region.
Methods
Based on forest resource inventory data and field sampling, this paper studied the carbon storage, its sequestration rate, and the potentials in the broad-leaved forests in the alpine region of the Qinghai-Xizang Plateau.
Important findings
The vegetation carbon storage in the broad-leaved forest accounted for 310.70 Tg in 2011, with the highest value in the broad-leaved mixed forest and the lowest in Populus forest among the six broad-leaved forests that include Quercus, Betula, Populus, other hard broad-leaved species, other soft broad-leaved species, and the broadleaved mixed forest. The carbon density of the broad-leaved forest was 89.04 Mg·hm^-2, with the highest value in other hard broad-leaved species forest and the lowest in other soft broad-leaved species forest. The carbon storage and carbon density in different layers of the forests followed a sequence of overstory layer > understory layer > litter layer > grass layer > dead wood layer, which all increased with forest age. In addition, the carbon storage of broad-leaved forest increased from 304.26 Tg in 2001 to 310.70 Tg in 2011. The mean annual carbon sequestration and its rate were 0.64 Tg·a^-1 and 0.19 Mg·hm^-2·a^-1, respectively. The maximum and minimum of the carbon sequestration rate were respectively found in other soft broad-leaved species forest and other hard broad-leaved species forest, with the highest value in the mature forest and the lowest in the young forest. Moreover, the carbon sequestration potential in the tree layer of broad-leaved forest reached 19.09 Mg·hm^-2 in 2011, with the highest value found in Quercus forest and the lowest in Betula forest. The carbon storage increased gradually during three inventory periods, indicating that the broad-leaved forest was well protected to maintain a healthy growth by the forest protection project of Qinghai Province and Xizang Autonomous Region.     

森林演替在南亚热带森林生态系统碳吸存中的作用

研究了鼎湖山南亚热带森林同一演替系列中3个不同演替阶段(马尾松针叶林、马尾松荷木混交林和季风常绿阔叶林)生态系统碳贮量和分配格局特征,并探讨了该地区森林演替过程中生态系统碳吸存潜力和速度。结果表明:(1)针叶林各组分碳素含量高于阔叶林对应组分的碳素含量(后者是前者的72.0%～94.5%)。两个森林植物碳素含量,不同层次比较,均为乔木层>灌木层>草本层,不同器官比较,以根或干最高。(2)乔木层生物量随森林演替进展而增加。针叶林、混交林和阔叶林乔木层生物量分别为:143.5t/hm2、270.1t/hm2和407.8t/hm2,其中大部分由干和皮组成(各器官占乔木层生物量的比例平均为:叶2.8%、枝19.3%、干和皮混合57.0%、根20.9%)。林下层生物量为4.23～14.10t/hm2,是乔木层的1.0%～9.8%,随森林演替进展而减少。(3)土壤容重随深度增加而增加,但随森林演替进展而减少。与土壤容重相反,土壤有机碳含量随深度增加而明显减少,但随森林演替进展而增加。(4)3种类型森林生态系统碳总贮量分别为135.8t/hm2、215.1t/hm2和259.7t/hm2。生态系统碳贮量在各组分的格局十分相似,植被、土壤和凋落物层所占比例均分别约为67.6%、30.2%和2.2%。与其它地带森林比较,鼎湖山保护区森林植被与土壤碳贮量之比和表层(0～20cm)的土壤碳占整个     

吉林省森林生态系统的碳储量、碳密度及其分布

利用森林资源二类调查汇总数据和标准地实测数据,研究吉林省森林生态系统的碳密度、碳储量及其组分和分布特征.结果表明:吉林省森林生态系统碳储量为1827.293TgC,其中乔木层、灌草层、枯落物层和土壤层的碳储量分别为439.152、5.195、45.600和1330.466TgC,分别占总碳量的24.1%、0.3%、2.5%和73.1%.吉林省森林生态系统碳密度为225.304MgC.hm-2,各层碳密度的大小顺序为土壤层(164.666MgC.hm-2)>乔木层(54.352MgC.hm-2)>枯落物层(5.644MgC.hm-2)>灌草层(0.643MgC.hm-2).不同类型森林生态系统碳储量在9.357～959.716TgC,碳密度在180.648～254.627MgC.hm-2之间,各林型分配特征表现为土壤层最大、灌草层最小.全省森林生态系统碳储量和碳密度的空间分布总体上为东部山区高、中西部平原地区低.吉林省森林中中龄林分比重大,若对现有森林加以更好的管理,可以增加其碳吸存潜力.     

Response of vegetation and soil carbon accumulation rate for China’s mature forest on climate change

Aims
This study aims to evaluate the impacts of future climate change on vegetation and soil carbon accumulation rate in China’s forests.
Methods
The vegetation and soil carbon storage were predicted by the atmosphere-vegetation interaction model (AVIM2) based on B2 climate change scenario during the period of 1981-2040. This study focused on mature forests in China and the forested area maintained constant over the study period. The carbon accumulation rate in year t is defined as the carbon storage of year t minus that of year t-1.
Important findings
Under B2 climate change scenario, mean air temperature in China’s forested area was projected to rise from 7.8 °C in 1981 to 9.0 °C in 2040. The total vegetation carbon storage was then estimated to increase from 8.56 Pg C in 1981 to 9.79 Pg C in 2040, meanwhile total vegetation carbon accumulation rate was estimated to fluctuate between -0.054-0.076 Pg C·a^-1, with the average of 0.022 Pg C·a^-1. The total soil carbon storage was estimated to increase from 30.2 Pg C in 1981 to 30.72 Pg C in 2040, and total soil carbon accumulation rate was estimated to vary in the range of -0.035-0.072 Pg C·a^-1, with the mean of 0.010 Pg C·a^-1. The response of vegetation and soil carbon accumulation rate to climate change had significant spatial difference in China although the two time series did not show significant trend over the study period. Our results also showed warming was not in favor of forest carbon accumulation, so in the northeastern and southeastern forested area, especially in the Changbai Mountain, with highest temperature increase in the future, the vegetation and soil carbon accumulation rate were estimated to decrease greatly. However, in the southern of southwestern forested area and other forested area, with relatively less temperature increase, the vegetation and soil carbon accumulation rate was estimated to increase in the future.     

四川森林植被碳储量的时空变化

利用平均木法建立森林生物量与蓄积量模型,结合四川森林资源二类调查数据,研究了森林碳密度和碳储量的时空变化.结果表明 四川森林碳储量从1974年的300.02 Tg增加到2004年的469.96 Tg,年均增长率1.51%,表明其是CO2的"汇".由于人工林面积的增加,森林植被的平均碳密度从49.91 Mg·hm-2减少到37.39 Mg·hm-2.四川森林碳储量存在空间差异性,表现为川西北高山峡谷区＞川西南山区＞盆周低山区＞盆地丘陵区＞川西平原区.森林碳密度由东南向西北呈现逐渐增加趋势,即盆地丘陵区＜川西平原区＜川西南山区＜盆周低山区＜川西北高山峡谷区.通过分区森林经营与管理将提高四川森林的碳吸存能力.     

基于森林清查资料的江西和浙江森林植被固碳潜力

以我国江西、浙江两省的森林植被为研究对象,基于1999-2003年间第六次全国森林清查数据及收集的1030个亚热带森林样地文献资料,依据林分生长的经验方程,估算了两个地区森林2004-2013年的固碳潜力,并基于455个样点的调查数据研究了不同森林管理措施(纯林间种、间伐、施肥)对森林未来固碳潜力的影响.结果表明:第六次森林清查以来的10年(2004-2013)间,江西森林植被年均自然固碳潜力约11.37 Tg C·a-1(1Tg=1012g),而浙江省森林植被年均自然固碳潜力约4.34 Tg C·a-1.纯林间种对江西、浙江两省森林植被固碳潜力影响最大,其次为间伐抚育,施肥的影响最小,纯林间种、间伐和施肥3种森林管理措施使江西省森林植被固碳潜力分别提高(6.54±3.9)、(3.81±2.02)和(2.35±0.6) Tg C·a-1,浙江省森林植被固碳潜力分别提高(2.64±1.28)、(1.42±0.69)和(1.15±0.29) Tg C·a-1.     

碳中和目标下中国森林固碳量跨期分配及成本

我国实现碳中和路线图的“碳排放达峰”、“快速降低碳排放”、“深度脱碳实现碳中和”3阶段具有复杂且差异的减排形势。森林固碳作为我国实现碳中和目标的重要手段,其跨期分配是平衡产业减排与森林固碳关系、降低我国实现碳中和的成本代价、以最优成本分步实现碳中和目标的重要途径。本研究从成本优化分配理论出发,引入森林边际固碳成本理论,结合国内现有产业边际减排理论,对我国实现碳中和3个阶段的成本变化过程进行模拟。结果表明: 我国在“碳排放达峰”、“快速降低碳排放”、“深度脱碳实现碳中和”3个阶段,实现成本最优的森林年固碳量分别为0.20、7.75、19.82亿t,分别占当期总减排量的1.8%、17.5%、37.6%。相较于仅依赖产业减排,在成本最优设计下发挥森林固碳成本优势,使得碳中和3个阶段的总成本分别降低0.48、791.36、9092.53亿美元。在“碳排放达峰”阶段,森林固碳的成本优势十分有限,应当主要依靠产业减排;在“快速降低碳排放”阶段,森林固碳的成本优势逐渐凸显;在“深度脱碳实现碳中和”阶段,应当充分发挥森林固碳的成本优势实现“零碳”目标,否则将会面临十分高昂的成本代价,尤其对于脱碳成本十分高昂或永远无法完全脱碳的产业。最优成本设计下森林固碳可以节约9884.37亿美元的碳中和成本。     

林火干扰对北方针叶林林下植被的影响

林下植被在北方针叶林植被群落中的物种多样性最高, 且具有较高的生物量周转率和地上部分净初级生产力, 对北方针叶林生态系统功能起着重要作用。火干扰是决定北方针叶林林下植被结构与功能的一个重要景观过程。该文综述了火干扰是如何通过与地形、火前林冠组成的交互作用而影响环境资源和林下植被的。最近的研究表明: 林下植被能够影响火后树木更新苗的定植、重建速率及森林演替轨迹; 林下植被还会通过影响元素的生物地球化学过程(凋落物降解和养分循环)影响林下环境资源的数量与异质性。因此, 研究火后初期北方针叶林林下植被的动态变化, 对于物种多样性保护和森林管理具有重要意义。     

辽宁省森林植被碳储量和固碳速率变化

利用CBM-CFS3模型,结合森林资源相关数据,研究辽宁省森林植被碳储量和固碳速率;并基于是否造林的两种假设情境,预测了未来辽宁省森林植被碳储量、碳密度和固碳速率的时空变化趋势.结果表明： 2005年辽宁省森林植被碳储量为133.94 Tg,碳密度为25.08 t·hm^-2,其中,栎类的碳储量最大,刺槐碳储量最小;落叶松和阔叶林碳密度较大,油松、栎类和刺槐碳密度基本相当.全省森林植被碳密度呈东高西低的分布规律,辽东地区由于森林多为成熟林和过熟林,未来植被碳密度增加潜力不大,辽宁南部和北部的中幼龄林未来将成为植被碳密度增长的高值区.在假设未来不造林的情景下,辽宁省森林植被碳储量上升缓慢,固碳速率下降较快;在无林地造林情景下,全省森林植被碳储量、固碳速率将明显提高.说明造林在增加森林植被碳储量和碳密度、提高森林的固碳速率中起到了重要作用.     

湖南省森林植被碳储量、碳密度动态特征

利用湖南省4次(1983—1987年、1990—1995年、2003—2004年和2009年)森林资源清查数据,采用材积源-生物量法,结合湖南省现有森林植被主要树种碳含量实测数据,研究近20多年来湖南省森林植被碳储量、碳密度的动态特征。结果表明:从1987年到2009年,湖南省乔木林植被碳汇为66.40×106tC,碳密度提高了5.65 tC/hm~2,阔叶林碳汇最大(48.43×10~6tC),其次是杉木林(9.54×10~6tC)和松木林(6.68×10~6tC),各乔木林植被碳密度波动较大;除过熟林外,各龄组乔木林均为碳汇,中龄林碳汇最大,幼龄林、中龄林、近熟林植被碳密度依次提高了4.75、4.09、0.83 tC/hm~2,成熟林、过熟林分别下降了6.87、13.88 tC/hm~2;天然林、人工林植被碳汇分别为41.01×10~6tC、25.39×10~6tC,碳密度分别提高了7.19、4.91 tC/hm~2。湖南省森林植被(包括疏林)碳汇为84.87×10~6tC,乔木林碳汇最大,其次是竹林,分别占湖南省森林植被碳汇的78.24%和33.31%,碳密度提高了6.24 tC/hm~2,各森林类型植被碳储量随其面积变化而变化。表明近20多年来,湖南省乔木林植被单位面积储碳能力明显提高,天然林在湖南省乔木林植被碳储量占有重要地位。