不同林龄杉木人工林碳储量及其分配格局

基于广西北部杉木主产区45块1000 m²样地的调查,研究幼龄林、中龄林、近熟林、成熟林、过熟林5种林龄杉木植被与土壤碳储量的分配格局.结果表明: 杉木人工林生态系统总碳储量表现为过熟林(345.59 t·hm^-2)>成熟林(331.14 t·hm^-2)>近熟林(299.11 t·hm^-2)>幼龄林(187.60 t·hm^-2)>中龄林(182.81 t·hm^-2).不同林龄碳储量分布格局均为土壤层>植被层>凋落物层,地下部分>地上部分.其中,植被层为34.80～134.55 t·hm^-2,占总碳储量的18.6%～38.9%,随林龄的增加而增加;凋落物层为1.26～2.07 t·hm^-2,占总碳储量的0.4%～1.1%;土壤层为149.24～206.02 t·hm^-2,占总碳储量的61.9%～80.0%.植被层碳储量以乔木层(33.51～133.7 t·hm^-2)最大,占92.8%～98.9%.其中,乔木层各器官碳储量以树干(20.98～95.68 t·hm^-2)最大,占乔木层碳储量的62.6%～72.6%,随林龄的增加而增加;枝、叶碳储量分别占4.8%～11.0%和11.1%～14.2%,随林龄的增加而减小,在过熟林阶段有所上升;根的碳储量占11.3%～12.3%,波动较小,比较稳定.     

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。     

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。     

浙江省森林生态系统碳储量及其分布特征

利用2011-2012年野外标准地实测资料, 结合第八次全国森林资源清查资料, 研究了浙江省森林生态系统碳储量及其分布特征。结果表明: 浙江省森林生态系统碳储量为602.73 Tg, 其中乔木层、灌草层、凋落物层和土壤层碳储量分别为122.88 Tg、16.73 Tg、11.36 Tg和451.76 Tg, 分别占生态系统碳储量的20.39%、2.78%、1.88%和74.95%; 在各森林类型中, 阔叶混交林碳储量为138.03 Tg, 所占比例最大(22.90%); 在森林各龄组中, 幼、中龄林约占浙江省森林生态系统碳储量的70.66%, 是碳储量的主要贡献者。浙江省森林生态系统平均碳密度为120.80 t·hm^-2, 乔木层、灌草层、凋落物层和土壤层碳密度分别为24.65 t·hm^-2、3.36 t·hm^-2、2.28 t·hm^-2和90.51 t·hm^-2。浙江省森林生态系统土壤层碳储量和生态系统碳储量呈极显著相关关系, 说明土壤层碳储量对浙江省森林生态系统碳储量贡献较大。浙江省天然林乔木层碳密度整体表现为过熟林>成熟林>近熟林>中龄林>幼龄林, 而人工林乔木层碳密度表现为过熟林>近熟林>成熟林>中龄林>幼龄林。浙江省幼、中龄林林分面积占比重较大, 占全省森林面积的76.76%, 若对现有森林进行更好的经营和管理, 可以增加浙江省森林的碳固存能力。     

湖南省杉木人工林生态系统碳储量分配格局及固碳潜力

人工林生态系统碳储量的空间分配格局对全球陆地碳循环有重要的影响,但湖南省杉木人工林生态系统碳储量的分配格局并不清楚。本研究在湖南省样地野外调查的基础上,结合第八次全国森林资源清查的结果,计算出湖南省杉木人工林生态系统的碳储量空间分布格局。结果表明:杉木人工林生态系统碳密度随着林龄增加而增加,幼龄林、中龄林和成熟林分别为125.70、138.57、193.72 Mg·hm~(-2);其中,幼龄林、中龄林和成熟林的植被生物量碳密度分别为18.72、38.86、62.48 Mg·hm~(-2);土壤碳密度随着林分发育先降低后增加,幼龄林为105.49 Mg·hm~(-2)、中龄林为97.23 Mg·hm~(-2)、成熟林126.7 Mg·hm~(-2);湖南省杉木人工林生态系统碳储量为307.48 Tg,其中幼龄林为90.57 Tg,中龄林为91.87 Tg,成熟林为125.31 Tg;湖南省杉木人工林生态系统的固碳潜力为85.56 Tg,其中,植被固碳潜力为47.19 Tg,土壤的固碳潜力为34.82 Tg。确定杉木人工林固碳潜力有助于量化人工林对碳汇的贡献及其制定实现潜力的森林经营管理措施。     

广西不同林龄喀斯特森林生态系统碳储量及其分配格局

基于广西喀斯特地区45块1000 m²样地的调查,研究幼龄林、中龄林、近熟林、成熟林、过熟林5个林龄阶段喀斯特森林植被与土壤碳储量的分配格局.结果表明: 广西不同林龄喀斯特森林总碳储量表现为幼龄林(86.03 t·hm^-2)＜近熟林(110.63 t·hm^-2)＜中龄林(112.11 t·hm^-2)＜成熟林(149.1 t·hm^-2)＜过熟林(244.38 t·hm^-2);各林龄阶段植被不同层碳储量分配均不同,乔木层所占比例占绝对优势,达到92.3%～98.7%,随林龄的增加而增长,灌木层、草本层、凋落物层所占比例分别为0.3%～1.9%、0.3%～1.2%和0.3%～2.5%,细根所占比例为0.3%～3.3%.土壤有机碳密度随土层深度的增加而递减,土壤层碳储量为51.75～81.21 t·hm^-2,所占生态系统比例为33.2%～66.2%,其随林龄的增大呈减小趋势.生态系统地上、地下部分碳储量分别为22.80～141.72和62.30～102.66 t·hm^-2,除过熟林外均为地下部分＞地上部分,地上碳储量随林龄的增大呈逐渐增加的趋势,地下碳储量的变化规律与土壤碳储量变化趋势一致.土壤层和乔木层为生态系统的主要碳库,二者所占比例达到了96%以上.     

青藏高原高寒区阔叶林植被固碳现状、速率和潜力

为明晰青藏高原高寒区阔叶林植被碳储量现状及其动态变化特征, 利用森林资源清查数据和标准样地实测数据, 估算了青藏高原高寒区(青海和西藏两省区)阔叶林植被的碳储量、固碳速率和固碳潜力。结果表明: 2011年青藏高原高寒区阔叶林植被碳储量为310.70 Tg, 碳密度为89.04 Mg·hm^-2。六类阔叶林型(栎(Quercus)林、桦木(Betula)林、杨树(Populus)林、其他硬阔林、其他软阔林和阔叶混交林)中, 阔叶混交林的碳储量最大, 杨树林碳储量最小; 其他硬阔林碳密度最大, 其他软阔林碳密度最小。空间分配上碳储量和碳密度表现为: 乔木层>灌木层>凋落物层>草本层>枯死木层。不同龄级碳储量和碳密度总体表现为随林龄增加逐渐增大的趋势。阔叶林碳储量从2001年的304.26 Tg增加到2011年的310.70 Tg, 平均年固碳量为0.64 Tg·a^-1, 固碳速率为0.19 Mg·hm^-2·a^-1。不同林型固碳速率表现为其他软阔林最大, 其他硬阔林最小; 不同龄级表现为成熟林最大, 幼龄林最小。阔叶林乔木层固碳潜力为19.09 Mg·hm^-2, 且不同林型固碳潜力表现为栎林最大, 桦树林最小。三次调查期间阔叶林碳储量逐渐增加, 主要原因是近年来森林保护工程的开展使阔叶林生长健康良好。     

祁连山青海云杉林生物量和碳储量空间分布特征

根据野外调查资料、祁连山地区青海云杉林相图和气象资料,在GIS技术的支持下估算了祁连山地区青海云杉林的生物量和碳储量及其空间分布.结果表明：2008年,研究区青海云杉林平均生物量为209.24 t·hm^-2,总生物量为3.4×10⁷ t;研究区水热条件的差异使青海云杉生物量在地理空间上存在较大的差异性;经度每增加1°,青海云杉生物量增加3.12t·hm^-2;纬度每增加1°,生物量减少3.8 t·hm^-2;海拔每升高100 m,生物量减少0.05 t·hm^-2;2008年,研究区青海云杉林碳密度在70.4～131.1 t·hm^-2,平均碳密度为109.8 t·hm^-2,幼龄林、中龄林、近熟林、成熟林和过熟林的平均碳密度分别为83.8、109.6、122、124.2和117.1 t·hm^-2,研究区青海云杉林总碳储量为1.8×10⁷ t.     

长白落叶松人工林乔木层生物量分布特征及其固碳能力研究

基于8~56 a长白落叶松人工林样地生物量调查数据,建立了长白落叶松林各器官生物量模型,探讨了不同林龄长白落叶松人工林干材、树皮、树枝、树叶、树根的生物量分布与变化规律及单木与林分乔木层的固碳能力。结果表明:随着林龄的增大,长白落叶松人工林林木及各器官生物量均呈现不同程度的增加趋势,单株木生物量由8 a时的0.174 kg增加至56 a时的328.196 kg,林分乔木层生物量由8 a时的0.519 t·hm-2增加至56 a时的251.39 t·hm-2,其中树干所占比例最大,且增幅最大。长白落叶松人工林单木平均碳储量为74.822 kg,56 a林分乔木层碳密度为130.455 t·hm-2,平均碳密度达63.113 t·hm-2,各器官碳储量变化规律明显。长白落叶松人工林幼龄林、中龄林、近熟林、成熟林林分乔木层的年平均固碳量分别为0.087、1.193、1.703、2.124 t·hm-2,固碳量年平均增长率排序为中龄林幼龄林成熟林近熟林。研究认为,长白落叶松人工林单株木及林分各器官生物量随林龄增加具有明显的变化规律,成熟林分固碳水平最高,中龄林分后期固碳潜力最大。     

小兴安岭7种典型林型林分生物量碳密度与固碳能力

森林生物碳储量作为森林生态系统碳库的重要组成部分, 在全球碳循环中发挥着重要作用。以小兴安岭7种典型林型为研究对象, 通过外业样地调查与室内实验分析相结合的方法, 从林分尺度对林分生物量与碳密度进行计量, 分析了林分生物碳储量的空间分配格局, 并对林分年固碳能力与碳汇潜力进行了探讨。结果表明: 小兴安岭不同林型从幼龄林到成熟林的乔木层碳密度增长速率为: 蒙古栎(Quercus mongolica)林>兴安落叶松(Larix gmelinii)林>云冷杉(Picea-Abies)林>樟子松(Pinus sylvestris var. mongolica)林>山杨(Populus davidiana)林>红松(Pinus koraiensis)林>白桦(Betula platyphylla)林。7种典型林型不同龄组(幼龄林、中龄林、近熟林和成熟林)林分生物量碳密度分别为: 红松林31.4、74.7、118.4和130.2 t·hm^-2; 兴安落叶松林28.9、44.3、74.2和113.3 t·hm^-2; 樟子松林22.8、52.0、71.1和92.6 t·hm^-2; 云冷杉林23.1、44.1、77.6和130.3 t·hm^-2; 白桦林18.8、35.3、66.6和88.5 t·hm^-2; 蒙古栎林25.0、20.0、47.5和68.9 t·hm^-2; 山杨林19.8、28.7、43.7和76.6 t·hm^-2。红松林、兴安落叶松林、樟子松林和蒙古栎林在幼龄林时林分年固碳量较高, 其他林型在成熟林时林分年固碳量较高。7种典型林型不同龄组的林分生物量碳密度均随林龄增长而增加, 但不同林型的碳汇功能存在差异, 同一林型不同林龄的生物量碳密度增幅差异也较大。林分年固碳量在0.4-2.8 t·hm^-2之间, 碳汇能力较强、碳汇潜力较大。尤其是小兴安岭目前林分质量较差, 幼龄林和中龄林所占的比重较大, 具有较大的碳汇潜力。研究结果可为森林经营管理及碳汇功能评价提供参考。     

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 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.     

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.     

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.     

宁夏回族自治区森林生态系统固碳现状

根据宁夏回族自治区森林资源清查资料以及野外调查和室内分析的结果,研究了宁夏地区森林生态系统固碳现状,估算了该区森林生态系统的碳密度、碳储量,并分析了其空间分布特征.结果表明: 宁夏森林各植被层生物量大小顺序为: 乔木层(46.64 Mg·hm^-2)>凋落物层(7.34 Mg·hm^-2)>细根层(6.67 Mg·hm^-2)>灌草层(0.73 Mg·hm^-2).云杉类(115.43 Mg·hm^-2)和油松(94.55 Mg·hm^-2)的单位面积植被生物量高于其他树种.不同林龄乔木层碳密度中,过熟林最高,但由于幼龄林面积所占比例最大,其乔木层碳储量(1.90 Tg C)最大.宁夏地区森林生态系统平均碳密度为265.74 Mg C·hm^-2,碳储量为43.54 Tg C,其中,植被层平均碳密度为27.24 Mg C·hm^-2、碳储量为4.46 Tg C,土壤层碳储量是植被层的8.76倍.宁夏地区的森林碳储量整体呈南高北低分布,总量较低.这与其森林面积小和林龄结构低龄化有很大关系.随着林龄结构的改善和林业生态工程的进一步实施,宁夏森林生态系统将发挥巨大的固碳潜力.