Above-Ground Carbon Sequestration during Restoration of Upland Evergreen Forest in Northern Thailand

Tropical deforestation reduces the global terrestrial carbon sink and substantially contributes towards global climate change. Conversely, tropical forest restoration could help to mitigate the problem, but few measurements of how much carbon can be absorbed by forest restoration have been published. Therefore, this study used a partial harvesting method to compare carbon sequestration among 11 framework tree species (selected to accelerate forest regeneration by suppressing weeds and attracting seed dispersers), in a restoration trial in northern Thailand. The goal was to enable restoration practitioners to factor in carbon sequestration, when selecting tree species to plant. Above-ground carbon sequestration was derived from wood density, tree volume and above-ground biomass of 3 trees of each of 12 tree species, in 5, 10 and 14-year old restoration plots (RF5, RF10 and RF14, respectively). Wood density did not vary significantly with tree age (p ≤ 0.05), but it did differ significantly among tree species (p ≤ 0.05). Gmelina arborea wood was the densest (0.57 ± 0.10 g/cm3). Carbon concentration of stem wood did not vary significantly among tree species or age (p ≤ 0.05), averaging 44.67% (±0.54). Tree volume varied among the species in the youngest plot, but such variation declined with tree age. In the oldest plot (RF14), Erythrina subumbrans and Spondias axillaris grew significantly larger than the other species and sequestered the most above-ground carbon: 135.23 and 115.87 kgC/tree respectively. Bischofia javanica sequestered the least, only 9.80 kgC/tree. An even framework species mix would sequester 13.2, 44.3 and 105.8 tC/ha, 5, 10 and 14 years respectively after planting and would achieve carbon storage levels similar to those of nearby natural forest in 16 - 17 years. The framework species method is therefore capable of rapidly accumulating carbon, a property which, along with its acceleration of biodiversity recovery and provision of a wide range of forest products and ecological services to local people, meets both the requirements and safeguards of REDD+ projects.

Future biomass carbon sequestration capacity of Chinese forests

Chinese forests, characterized by relatively young stand age, represent a significant biomass carbon （C） sink over the past several decades. Nevertheless, it is unclear how forest biomass C sequestration capacity in China will evolve as forest age, climate and atmospheric CO2 concentration change continuously. Here, we present a semi-empirical model that incorporates forest age and climatic factors for each lbrest type to estimate the effects of forest age and climate change on total forest biomass, under three different sce-narios based on the fifth phase of the Coupled Model Intercomparison Project （CMIPS）. We estimate that age-related forest biomass C sequestration to be 6.69 Pg C （~0.17 Pg C a^-1） from the 2000s to the 2040s. Climate change induces a rather weak increase in total forest biomass C sequestration （0.52-0.60 Pg C by tile 2040s）. We show that rising CO2 concentrations could further increase tile total forest biomass C sequestration by 1.68-3.12 Pg C in the 2040s across all three scenarios. Overall, the total forest biomass in China would increase by 8.89-10.37 Pg C by the end of 2040s. Our findings highlight the benefits of Chinese afforestation programs, continued climate change and increasing CO2. concentration in sustaining the forest biomass C sink in the near future, and could therefore be useful for designing more realistic climate change mitigation policies such as continuous forestation programs and careful choice of tree species.

Carbon Sequestration Effects of Shrublands in Three-North Shelterbelt Forest Region, China

Three-North Shelterbelt Forest （TSF） program, is one of six key forestry programs and has a 73-year construction period, from 1978 to 2050. Quantitative analysis of the carbon sequestration of shrubs in this region is important for understanding the overall function of carbon sequestration of the forest and other terrestrial ecosystems in China. This study investigated the distribution area of shrubland in the TSF region based on remote sensing images in 1978 and 2008, and calculated the carbon density of shrubland in combination with the field investigation and previous data from published papers. The carbon sequestration quantity and rate from 1978 to 2008 was analyzed for four sub-regions and different types of shrubs in the TSF region. The results revealed that： 1） The area of shrubland in the study area and its four sub-regions increased during the past thirty years. The area of shrubland for the whole region in 2008 was 1.2 × 10^7 ha, 72.8% larger than that in 1978. The Inner Mongolia-Xinjiang Sub-region was the largest shrubland distribution area, while the highest coverage rate was found in the North China Sub-region. 2） In decreasing order of their carbon sequestration, the four types of shrubs considered in this study were Hippophae rhamnoides, Caragana spp., Haloxylon ammodendron and Vitex negundo vat. heterophylla. The carbon sequestration of/-/, rhamnoides, with a maximum mean carbon density of 16.5 Mg C/ha, was significantly higher than that of the other three species. 3） The total carbon sequestration of shrubland in the study region was 4.5 x 107 Mg C with a mean annual carbon sequestration of 1.5× 10^6 Mg C. The carbon density in the four sub-regions decreased in the following order： the Loess Plateau Sub-region, the North China Sub-region, the Northeast China Sub-region and the Inner Mongolia-Xinjiang Sub-region. The paucity of studies and data availability on the large-scale carbon sequestration of shrub species suggests this study provides a baseline reference for future research in this area.

Huge Carbon Sequestration Potential in Global Forests

Forests play an important role in mitigating climate change by absorbing carbon from atmosphere. The global forests sequestrated 2.4±0.4 Pg C y^-1 from 1990 to 2007, while the quantitative assessment on the carbon sequestration potential （CSP） of global forests has much uncertainty. We collected and compiled a database of site above-ground biomass （AGB） of global mature forests, and obtained AGB carbon carrying capacity （CCC） of global forests by interpolating global mature forest site data. The results show that： （i） at a global scale, the AGB of mature forests decline mainly from tropical forests to boreal forests, and the maximum AGB occurs in middle latitude regions; （ii） temperature and precipitation are main factors influencing the AGB of mature forests; and （iii） the above-ground biomass CCC of global forests is about 586.2±49.3 Pg C, and with CSP of 313.4 Pg C. Therefore, achieving CCC of the existing forests by reducing human disturbance is an option for mitigating greenhouse gas emission.

Carbon Sequestration in Forest Vegetation of Beijing at Sublot Level

Based on forest inventory data (FID) at sublot level,we estimated the carbon sequestration in forest vegetation of Beijing,China in 2009.In this study,the carbon sequestration in forest vegetation at sublot level was calculated based on net biomass production (ΔB) which was estimated with biomass of each sublot and function relationships between ΔB and biomass.The biomass of forested land was calculated with biomass expansion factors (BEFs) method,while those of shrub land and other forest land types were estimated with biomass,coverage and height of referred shrubs and shrub coverage and height of each sublot.As one of special forested land types,the biomass of economic tree land was calculated with biomass per tree and tree number.The variation of carbon sequestration in forest vegetation with altitude,species and stand age was also investigated in this study.The results indicate that the carbon sequestration in forest vegetation in Beijing is 4.12 × 106 tC/yr,with the average rate of 3.94 tC/(ha·yr).About 56.91% of the total carbon sequestration in forest vegetation is supported by the forest in the plain with an altitude of < 60 m and the low mountainous areas with an altitude from 400 m to 800 m.The carbon sequestration rate in forest vegetation is the highest in the plain area with an altitude of < 60 m and decreased significantly in the transitional area from the low plain to the low mountainous area with an altitude ranging from 200 m to 400 m due to intensive human disturbance.The carbon sequestration of Populus spp.forest and Quercus spp.forest are relatively higher than those of other plant species,accounting for 25.33% of the total.The carbon sequestration in vegetation by the forest of < 40 years amounts to 45.38% of the total.The carbon sequestration rate in forest vegetation peaks at the stand age of 30–40 years.Therefore,it would be crucial for enhancing the capability of carbon sequestration in forest vegetation to protect the forest in Beijing,to limit human disturbance in the transitional area from the plain to the low mountain area,and to foster the newly established open forest.

Carbon storage in evergreen broad-leaf forests in mid-subtropical region of China at four succession stages

To better understand the effect of forest succession on carbon sequestration, we investigated carbon stock and allocation of evergreen broadleaf forest, a major zonal forest in subtropical China. We sought to quantify the carbon sequestration potential. We sampled four forest types, shrub （SR）, pine （Pinus massoniana） forest （PF）, pin~ and broadleaf mixed forest （Mr） and evergreen broadleaf forest （BF）. A regression equation was constructed using tree height and diameter at breast height （DBH） and elements of total tree biomass. The equation was subse- quently utilized to estimate tree carbon storage. The carbon storage of understory, litter, and soil was also estimated.

森林固碳计量方法研究综述

森林在全球碳循环中扮演着关键角色,不仅有助于减缓气候变化,还在改善生态环境、促进社会经济可持续发展等方面发挥着重要作用。虽然以往的研究也探讨了森林固碳计量方法,但大多数集中在地上部分,且缺乏对基础理论的深入探讨。本研究针对前人研究的不足,从基础理论分析出发,探讨森林固碳的特点、过程及其影响机制,重点分析了植物、土壤和凋落物的固碳计量方法。综述了各方法在不同测算尺度下的应用效果,系统比较了各方法的优势和局限性。最后,讨论了当前研究重点和发展趋势。研究表明,各种森林固碳计量方法皆有一定的局限性,估算精度各异。因此,研究者应根据现有数据、计量尺度和精度需求,合理选择最适宜的计量方法。本文有助于深入理解森林固碳机制、掌握森林固碳计量方法,可为森林经营管理和应对气候变化策略提供科学依据。

油松主要分布区林分碳储量特征与固碳潜力

根据北京市、河北省、辽宁省、陕西省、内蒙古自治区的油松(Pinus tabuliformis)资源二类调查数据,使用材积源生物量法结合油松含碳率计算中国油松主要分布区油松林碳储量与碳密度,分析不同地区、龄组、林种、起源的油松林碳储量分布特征与固碳潜力。结果表明:油松5个主要分布区的油松林总面积为243.09万hm^(2)、总蓄积为11175.75万m^(3)、总碳储量为5043.38万t,平均碳密度为20.75 t·hm^(-2)。油松天然林碳储量为1660.14万t,碳密度为25.77 t·hm^(-2)。油松人工林碳储量为3383.24万t,碳密度为18.94 t·hm^(-2)。油松人工林碳储量高于天然林,占全部碳储量的67.08%。不同龄组中,碳储量最大是油松中龄林,为2032.38万t,占全部碳储量的40.30%;碳储量最小的为过熟林,占全部碳储量的2.32%。油松各龄组平均碳密度随林龄的增加而增加。不同林种中,碳储量来源主要为防护林及用材林,共为4360.45万t,占全部碳储量的86.46%。5处主要分布区的油松林固碳潜力为5285.63万t,相当于现有油松碳储量的1.88倍,其中,中幼龄林固碳潜力为4904.46万t,是油松林固碳潜力所在。油松林具有明显的固碳增汇能力,其人工林为油松碳库的主体,中幼龄油松林具有巨大的固碳潜力,需加强油松人工中幼龄林的抚育及管理。

浙江省竹林碳汇测算研究

采用生物量法测算浙江省竹林固碳量,运用能源活动二氧化碳排放测算法估算浙江省碳排放量,将二者进行对比分析竹林碳汇贡献。结果表明:1973—2021年浙江竹林固碳量从1820.64万t增长到3570.88万t,净增长量为1750.24万t,增长率高达96.13%,总体呈现增加的趋势,其中毛竹林为主要固碳林种;浙江省碳排放量呈现出稳定增长的趋势,增长率在2004—2021年有所下降;竹林固碳量与碳排放量呈现趋同的增长趋势,但竹林固碳量对于整体的碳排放量而言占比较小,固碳贡献小。为有效助力浙江省碳达峰、碳中和目标进程,提出应注重稳定竹林碳汇增量、切实巩固竹林碳汇发展,规范引导碳汇经营方案、合理提高竹林碳汇潜力,有效结合企业碳汇主体、科学管控企业排放数量,以此有效发挥竹林碳汇价值。

中国森林乔木林碳储量及其固碳潜力预测

加强对我国森林碳储量和固碳潜力的研究,是制定中国增汇减排政策的重要依据,对我国国际气候谈判和全面了解森林碳汇潜力具有重要作用。利用我国第七次和第八次森林资源清查中各优势树种的面积和蓄积量数据,采用IPCC材积源生物量法(volume-biomass method),估算了我国森林(乔木林)碳储量和碳密度及其分布,分析我国不同省份天然乔木林和人工乔木林碳储量龄组结构特征;建立分区域、分起源主要优势树种的单位面积蓄积-林龄Logistic生长方程,结合我国森林2020年和2030年面积蓄积增长目标,预测我国乔木林2010—2050年间碳汇潜力。结果表明:第八次清查期间中国乔木林总碳储量为6135.68 Tg,碳密度为37.28 Mg/hm2;天然乔木林和人工乔木林的碳储量分别为5246.07 Tg和889.61 Tg,分别占总碳储量的85.50%和14.50%。到2050年,中国乔木林和新造林的总碳储量和平均碳密度将分别达到11125.76 Tg和52.52 Mg/hm2,与2010年相比分别增加81%和41%。分析结果表明中国乔木林有很大的碳汇潜力,将在应对和减缓全球气候变化中发挥重要作用。

施肥对巨桉幼树生长及生物固碳量的影响

桉树Eucalyptus作为世界三大速生树种之一,广泛用于营造人工林,其中巨桉Eucalyptus grandis以生长速度快和经济效益好而成为目前栽培面积最大的一种桉树。以不施肥为对照,研究不同施肥水平(含氮、五氧化二磷和氧化钾各15%的复合肥0,90,180,270 g·株-1)下巨桉的生长及生物固碳量。结果表明:施肥90～270 g·株-1与不施肥条件下相比,巨桉地径、冠径、树高、整株生物量和根冠比分别增加16.3%～38.3%,17.1%～44.5%,15.8%～45.5%,21.8%～59.5%和2.1%～5.8%,且地径、冠径、整株生物量以及生物固碳量都显著大于不施肥处理;施肥180 g·株-1的地径和树高与270 g·株-1和90 g·株-1差异均不显著,但施肥270 g·株-1均显著高于90 g·株-1,施肥90 g·株-1的树高与不施肥处理间的差异不显著;各施肥水平下的冠径之间存在显著性差异。地径、冠径和树高生长速度与施肥量呈极显著正相关关系(P<0.01),且在7月和8月的生长速度相对较快。除施肥270.株-1外,其他施肥处理的根冠比与不施肥处理差异不显著,各施肥水平的整株生物量和生物固碳量之间均存在显著性差异。说明在试验地条件下0～270 g·株-1肥料用量范围内增加施肥量有利于促进巨桉生长,提高生物量和生物固碳量以及根冠比。这对巨桉林的科学施肥管理以及缓解全球气候变化具有重要的作用。

浙江省杉木生态公益林碳储量效益分析

研究浙江省3个年龄级杉木优势林和含杉木混交林的生物量及其分布和碳储量。结果表明:杉木优势林依靠高密度种植和人工管理,在前10年乔木层生物量达到47t·hm-2以上,在中龄林(11～20年)及成熟林(21～30年)阶段杉木优势林乔木层生物量增加很少,且都低于同龄级的含杉木混交林;含杉木混交林乔木层的生物量随着林龄增加明显增加,中龄林比幼龄林增长了147%,成熟林比中龄林增长了28.1%;若杉木优势林改造为含杉木的混交林,碳储量至少增加0.84t·hm-2a-1;若不改良,碳储量至多增加0.21t·hm-2a-1。

青海省森林生态系统植被固碳现状研究

科学评估区域森林碳储量动态、固碳现状及其增汇潜力对理解陆地生态系统碳循环以及源汇功能具有重要意义。利用青海省第三次(1989-1993年)至第六次(2004-2008年)森林资源清查资料,以及不同树种生物量和蓄积量之间的线性关系,对青海省近19年来森林碳储量进行了求和估算。结果表明:1青海省森林面积从1989年的246.5×104hm2增加到2008年的355.0×104hm2。2青海省4次森林资源清查中森林植被整体碳储量从1989年的814.34×104t增加到2008年的1118.26×104t,增加了303.92×104t,年均增加(19a)159.96×104t,年均增长率1.68%,表明19年间青海森林植被碳汇作用不断增强,储碳能力将随森林面积的增加逐渐增加,青海省的森林是CO2的"汇"。3青海省1989-2008年间主要森林类型碳增汇量为柏木>桦木>杨树>云杉,可见这几种林分类型在全省森林植被碳汇功能中占有重要的地位。如果对现有森林进行更好地抚育和管理,青海省森林作为CO2"汇"的潜力很大。

南亚热带3种常绿阔叶次生林的生物量结构和固碳现状

相对准确地计量地带性森林碳库大小是估算区域森林碳汇潜力的前提。选择我国南亚热带地区受生态公益林保护近三四十年的3种常绿阔叶次生林:鹿角锥(Castanopsislamontii)+木荷(Schimasuperba)次生林(简称为LJZ)、华润楠(Machiluschinensis)+小红栲(C.carlesii)+黄杞(Engelhardtiaroxburghiana)次生林(简称为HRN)、罗浮栲(C.faberi)+木荷+黎蒴(C.fissa)次生林(简称为LFK),开展完整的植被生物量和土壤碳库调查,并对其碳库结构进行分析。结果表明,(1)鹿角锥+木荷林、华润楠+小红栲+黄杞林、罗浮栲+木荷+黎蒴林植被总生物量分别为235.0、231.0、261.9 t·hm^(-2),0~100cm土壤碳库分别为126.6、148.1、104.6 t·hm^(-2);采用0.45植物含碳率计算生物量碳库,则整个生态系统碳库分别为232.4、252.1、222.5 t·hm-2。(2)3种次生林总生物量的组成中,乔木层生物量比例最大,介于87%~93%,接下来为枯死木生物量比例,灌木层、草本层、凋落物层和细根(≤2 mm)的生物量比例大多在1%~2%之间。(3)3种林型乔木层生物量胸径级分布存在差异,其中,鹿角锥+木荷林和罗浮栲+木荷+黎蒴林近似正态分布,最大比例胸径级为15~20 cm,分别占总生物量的30%和36%。华润楠+小红栲+黄杞林则表现为随胸径级增加比例增大的趋势,其最大比例胸径级为35 cm以上,占总生物量的37%。(4)3种林型乔木层生物量不同组分比例大小顺序一致,即树干>树根>树枝>树叶,且同一组分在不同林型所占比例相差较小,树干、树枝、树叶和树根比例分别约为46%、19%、3%和32%。(5)参照南亚热带顶极演替阶段季风常绿阔叶林,该研究的3种次生林碳汇潜力主要在植被固碳上,而土壤固碳潜力有限。该研究全面地计量了我国南亚热带地区3种不同群落组成的常绿阔叶次生林碳库现状,这对评估该地区较大面积的仍受干扰的次生林、低效改造林和新造乡土树种混交林等低效森林未来几十年的固碳潜力具有重要参考价值。

森林碳蓄积量估算方法及其应用分析

近些年来,森林锐减、土地退化、环境污染、生物多样性丧失,特别是人类活动产生的C02浓度急剧上升和由此导致的温室效应等是目前人类面临最严峻的全球环境变化问题,所以全球碳循环问题日益成为全球变化与地球科学研究领域的前沿与热点问题,其中陆地生态系统碳循环又是全球碳循环中最复杂、受人类活动影响最大的部分。而森林生物量占整个陆地生态系统生物量的90%,因此,为了正确评估森林在全球碳平衡中的作用,了解森林生态系统在碳循环中的作用,森林的碳动态研究正日益成为人们关注的重点。本文总结了估算森林固碳量的几种方法——样地清查法、模型模拟法和遥感估算法,分析了它们的特点及应用等有关问题。

基于森林资源二类调查数据的重庆市森林碳储量估算研究

根据重庆市2010年森林资源规划设计调查数据资料,采用森林蓄积量扩展法等对重庆市森林植被碳储量进行了分析研究。结果表明:重庆市森林植被碳储量达15 918.95万t,折合CO2约为58 422.55万t。其中乔木林碳储量为13 697.22万t,占总碳储量的86.04%;乔木经济林75.12万t,占总碳储量的0.47%;竹林1 838.23万t,占总碳储量的11.55%;国家特别规定灌木林308.38万t,占总碳储量的1.94%。表明重庆市森林碳储量较大,碳汇能力强。

湖南主要森林类型碳汇功能及其经济价值评价

利用湖南省森林资源主要数据汇编(1999—2003年),依据不同森林类型生物量与蓄积量之间的回归方程,对湖南省几种主要森林类型的生物量和碳贮量进行了推算,分析了不同林龄结构的碳密度以及天然林与人工林的碳贮量,并对整个湖南省的森林经济价值进行估算。结果表明:湖南省主要森林类型的总碳贮量为94.935 Tgc,碳汇总经济价值为70 723.26万元,固定CO2的经济效益达259 554.36万元。阔叶树的碳汇能力最强,其次是杉木和马尾松;湖南省的天然林和人工林的碳贮量相差不大,不同龄组碳密度高低排序的基本规律是:过熟林>成熟林>近熟林>中龄林>幼龄林;而中龄林的碳贮量最多,过熟林碳贮量最少。

重庆市渝北区森林碳汇量估算研究

碳汇一般是指从空气中清除二氧化碳的过程、活动、机制。在林业中主要是指植物吸收大气中的二氧化碳并将其固定在植被或土壤中,从而减少该气体在大气中的浓度。重庆市渝北区作为国家级开发区"两江新区"的重要组成部分,对区域内的森林碳汇量进行估算将提供重要参考与实践意义,本文应用目前比较成熟的森林碳汇量计算方法,在计算出森林生物量的基础上,针对渝北全区进行了碳汇量的计算。结果表明:碳汇总量已达到724 301.019 63 t。

森林经营碳汇项目计量研究——以重庆万州马尾松林分为例

以重庆万州马尾松林分为例,对森林经营碳汇项目进行碳汇计量研究。结果表明,项目期30年基线情景下的碳汇量累计为57552 tC,项目情景下的碳汇量累计为180572 tC,是基线情景下的3.13倍;项目净碳汇量为123020 tC,换算成CO2当量为451074tCO2-e,年均碳汇量为2.89t CO2-e/hm2。通过森林经营可有效增加碳储量,增强碳汇能力,对建立碳汇效益补偿机制、完善碳汇交易市场、改善生态环境、应对区域气候变化有着重要意义。

黄山松天然林生物量动态预估模型及碳汇价值潜力研究

为解决异龄林平均年龄不易确定的问题,以理查德方程为基础模型,通过推导,构建了以间隔期为自变量、立地质量等级为哑变量的林分生物量动态预估模型,根据哑变量的取值特点,引入了免疫进化算法来估计模型参数,拟合效果较佳,并通过了适用性检验。在此基础上,利用林分实测数据说明了模型的运用,计算了不同间隔期和立地质量等级下的林分生物量,分析了林分碳汇的变化情况,根据碳汇价值计算公式估算了不同立地质量等级下的碳汇价值潜力,为国家节能减排政策的制定、应对气候变化、环境监测提供技术保障。