森林在减缓全球气候变暖中的重要作用

温室效应引起全球变暖和气候变化,影响社会经济的发展,危及人类的生存,是当今世界最重要的生态问题之一。减缓和控制这一过程的最重要的手段之一就是造林固碳。1温室气体与气候变暖包裹着地球表面的大气层中,含有少量的二氧化碳、甲烷等气体。它们含量虽低,但作用巨大。它们通过吸收地球反射的太阳能而温暖了大气,并稳定了地球表面的温度。这就是温室效应。《联合国气候变化框架公约》把温室气体定义为:“大气中那些吸收和重新放出红外幅射的自然和人为的气体。”其中主要成分是二氧化碳,约占温室气体总量的61%。温室气体的存在使地球表面的…     

增加森林碳汇是应对气候变化的重要途径

最近，一系列科学研究证实，二氧化碳等温室气体排放与全球气候变化之间存在着直接的关系。工业革命开始前，大气中二氧化碳浓度基本维持在280ppm（1ppm为百万分之一）左右，现在已经上升到387ppm左右。大气中的二氧化碳等温室气体会阻碍地面的逆辐射（长波辐射），导致地球表面热量不能正常散发，使气温上升，这就是所谓的“温室效应”。为了应对全球气候变暖，最主要的措施之一就是努力减少二氧化碳的排放。     

我国湿地生态系统温室气体排放的研究现状

温室气体是指大气中自然或人为产生的的气体成分,它们能够吸收和释放地球表面、大气和云发出的热红外辐射光谱内特定波长的辐射。该特性导致温室效应。水汽（H2O）、二氧化碳（CO2）、氧化亚氮（N2O）、甲烷（CH4）和臭氧（O2）是地球大气中主要的温室气体。此外,大气中还有许多完全人为产生的温室气体等,如卤烃和其它含氯和含溴的物质,六氟化硫（SF6）、氢氟碳化物（HFC）和全氟化碳（PFC）也定为温室气体。     

浅谈“温室效应”与未来的林火管理

随着现代化工业的迅速发展,大量的化石燃料,如煤、石油和其它薪炭柴被燃烧利用,加之地球上森林资源日益减少,使得大气中二氧化碳的含量急剧增加,它和其它气体如甲烷类、二氧化氮等一道加厚了地球表面大气中的保温层,阻止地     

不可忽视的地球升温

太阳光照到地球表面 ,使地球变热 ,同时地球也向空间散发热量 ,大气中的水气 ,二氧化碳。甲烷及其它一些气体即温室气体 ,它们不会阻挡太阳能传给地球 ,但能储存一部分地球向外散发的热量 ,使地球表面具有较高的温度 ,这是地球上能够出现生命和维持生命存在的原因之一 ,这种吸热散热在现代工业出现以前是相对平衡的 ,那时地球的平均温度一直维持在１３℃左右。近几十年来 ,大规模的人类活动以及现代工业的发展使大气组成发生了惊人的变化 ,大量温室气体正在大气下层集聚 ,这种趋势继续下去 ,很可能导致全球气候变暖 ,这种现象叫做温室效应。…     

全球碳循环

<正>全球碳循环指碳在地球各个圈层(大气圈、水圈、生物圈、土壤圈、岩石圈)之间的迁移转化和循环周转的过程。在大气中,二氧化碳是含碳的主要气体,也是碳参与物质循环的主要形式。它的主要过程包括:(1)生物的同化过程和异化过程,主要是光合作用和呼吸作用;(2)大气和海洋之间的二氧化碳交换;碳酸盐的沉淀作用。碳循环途径主要有:(1)在光合作用和呼吸作用之间的细胞水平上的循环;(2)大气二氧化碳和植物之间的个体水平上     

全球碳循环

<正>全球碳循环指碳在地球各个圈层(大气圈、水圈、生物圈、土壤圈、岩石圈)之间的迁移转化和循环周转的过程。在大气中,二氧化碳是含碳的主要气体,也是碳参与物质循环的主要形式。它的主要过程包括:①生物的同化过程和异化过程,主要是光合作用和呼吸作用;②大气和海洋之间的二氧化碳交换;碳酸盐     

亚热带典型丘陵坡地马尾松林土壤N2O的年通量特征

由人类活动所造成的大气中温室气体浓度急剧增加而引起的全球气候变暖和环境变化已引起全世界的广泛关注。氧化亚氮(N2O)是仅次于二氧化碳(CO2)和甲烷(CH4)的一种温室气体,在大气中含量较低却十分稳定,具有较大的增温潜能(其单分子的增温潜能是CO2的310倍)和较快的浓度增加速率(以每年0.25%的速率增加)(IPCC,2007)。N2O可吸收红外线,减少地球表面通过大气向外层空间的热辐射,导致地球表面温度增加。N2O能参与大气中许多光化学反应,破坏臭氧层(Crutzen,1970),导致到达地球表面的紫外线明显增加,给人类健康和生态环境带来多方面的危害。     

遏制地球变暖的新思路:人造森林

全球气候变暖的原因之一是人类排放的二氧化碳等温室气体太多,减少大气中的二氧化碳是遏制全球气候变暖的重要方法.     

植绿护绿从我做起保护我们共有的家园

近年来,全球生态环境形势严峻,尤以气候变暖表现突出。由于全球工业化造成大量二氧化碳等温室气体排放到大气中,使地球生态失衡,气候变暖。温室气体的过量排放,打破了大气平衡,导致温度升高,使得北极冰川融化速度加快,由此引发的两种可怕后果正在逐步显现。一种是海平面上升,威胁沿海地区经济社会发展。据统计,近百年来,我国平均气温升高了0．5℃-0．8℃,近50年变暖尤其明显,使海平面上升了十几厘米。     

Forest carbon offsets and carbon emissions trading: Problems of contracting

The process of monitoring and measuring the carbon fluxes associated with forestry is complex and costly, and the process is subject to asymmetric information, perverse incentives and inadequate institutions. The upshot is that any trade in forestry related carbon credits is likely to involve unwarranted acts of faith. This means that, since carbon credits are a de facto fiat currency, their exchange value is likely to be unstable. Contracting requires good governance, which is often lacking. Meanwhile, parties to a contract to provide offsets for sale in carbon markets have misaligned incentives in addition to asymmetric information. This leads to a principal-agent problem that delays successful contracting and quite often leads to incompatible claims regarding the creation of carbon offsets. At worse, it results in corruption.     

Ecophysiological responses and carbon distribution ofPinus koraiensis seedlings to elevated carbon dioxide

The net CO₂ assimilation rate, stomatal conductance, RuBPcase (ribulose 1,5-biphosphate carboxylose) activity, dry weight of aboveground and belowgroud part, plant height, the length and diameter of taproot ofPinus koraiensis seedlings were measured and analyzed after six-week exposure to elevated CO₂ in an open-top chamber in Changbai Mountain of China from May to Oct. 1999. Seedlings were planted in four different conditions: on an open site, control chamber, 500 μL·L⁻¹ and 700 μL·L⁻¹ CO₂ chambers. The results showed that the total biomass of the seedlings increased whereas stomatal conductance decreased. The physiological responses and growth to 500 μL·L⁻¹ and 700 μL·L⁻¹ CO₂ varied greatly. The acclimation of photosynthesis was downward to 700 μL·L⁻¹ CO₂ but upward to 500 μL·L⁻¹ CO₂. The RuBPcase activity, chlorophyll and soluble sugar contents of the seedlings grown at 500 μL·L⁻¹ CO₂ were higher than that at 700 μL·L⁻¹ CO₂. The concentration 500 μL·L⁻¹ CO₂ enhanced the growth of aboveground part whereas 700 μL·L⁻¹ CO₂ allocated more carbon to belowground part. Elevated CO₂ changed the carbon distribution pattern. The ecophysiological responses were significantly different between plants grown under 500 μL·L⁻¹ CO₂ and 700 μL·L⁻¹ CO₂. Foundation Item: This paper was supported by Chinese Academy of Sciences. Biography: HAN Shi-jie (1956-), male, Ph. Doctor, Professor in Laboratory of Ecological Process of Trace Substance in Terrestrial Ecosystem, Institute of Applied Ecology, Chinese Academy of Sciences. Responsible editor: Chai Ruihai     

Ecophysiological responses and carbon distribution of Pinus koraiensis seedlings to elevated carbon dioxide

The net CO2 assimilation rate, stomatal conductance, RuBPcase (ribulose 1,5-biphosphate carboxylose) activity, dry weight of aboveground and belowground part, plant height, the length and diameter of taproot of Pinus koraiensis seedlings were measured and analyzed after six-week exposure to elevated CO2 in an open-top chamber in Changbai Mountain of China from May to Oct. 1999. Seedlings were planted in four different conditions: on an open site, control chamber, 500 μ L.L-1 and 700 μL.L-1 CO2 chambers. The results showed that the total biomass of the seedlings increased whereas stomatal conductance decreased. The physiological responses and growth to 500 μL.L-1 and 700 μ L.L-1 CO2 varied greatly. The acclimation of photosynthesis was downward to 700 μL.L-1 CO2 but upward to 500 μ L.L-1 CO2. The RuBPcase activity, chlorophyll and soluble sugar contents of the seedlings grown at 500 μL.L-1 CO2 were higher than that at 700 μ L.L-1 CO2. The concentration 500 μ L.L-1 CO2 enhanced the growth of aboveground part whereas 700 μL.L-1 CO2 allocated more carbon to belowground part. Elevated CO2 changed the carbon distribution pattern. The ecophysiological responses were significantly different between plants grown under 500 μL.L-1 CO2 and 700 μL.L-1 CO2.     

Potential impacts of carbon taxes on carbon flux in western Oregon private forests

This study considers a carbon tax system as a policy tool for encouraging carbon sequestration through modification of management in existing forests and examines its welfare impacts and costs of the carbon sequestered. The simulated carbon tax leads to reduced harvest and increased carbon stock in the standing trees and understory biomass. Changes in the level of silvicultural investments vary by owner, depending on the nature of their initial inventory. In general investment under the tax is concentrated in regimes that establish faster growing plantations. Average rotation age increases, varying in extent across ownerships and site qualities. The carbon tax reduces both consumer and producer surpluses in regional timber markets. Producers are compensated by the carbon subsidies, except at low carbon tax levels. Not all rates of carbon tax will attract interest from private owners if participation is voluntary. Estimates of the marginal cost of sequestering carbon in western Oregon private forests are shown to be within the range of costs for projects considering afforestation alone in some eastern regions of the United States.     

DESPOT, a process-based tree growth model that allocates carbon to maximize carbon gain

We present a new model of tree growth, DESPOT (Deducing Emergent Structure and Physiology Of Trees), in which carbon (C) allocation is adjusted in each time step to maximize whole-tree net C gain in the next time step. Carbon gain, respiration and the acquisition and transport of substitutable photosynthetic resources (nitrogen, water and light) are modeled on a process basis. The current form of DESPOT simulates a uniform, monospecific, self-thinning stand. This paper describes DESPOT and its general behavior in comparison to published data, and presents an evaluation of the sensitivity of its qualitative predictions by Monte Carlo parameter sensitivity analysis. DESPOT predicts determinate height growth and steady stand-level net primary productivity (NPP), but slow declines in aboveground NPP and leaf area index. Monte Carlo analysis, wherein the model was run repeatedly with randomly different parameter sets, revealed that many parameter sets do not lead to sustainable NPP. Of those that do lead to sustainable growth, the ratios at maturity of net to gross primary productivity and of leaf area to sapwood area are highly conserved.     

红树林碳储量及碳汇效能研究的发展趋势和特征

为了解红树林碳储量及碳汇效能研究的发展趋势和特征,使用文献计量分析方法对基于Web of Science和中国知网(CNKI)数据库检索获得的文献进行统计分析。有关红树林碳汇效能研究的发文量逐年增加。美国和澳大利亚是该研究领域的两大强国,占据领先地位;这两个国家在世界排名前10位机构和作者上均占据明显的优势,其中发文量前10名机构中有5个来自美国,有3个来自澳大利亚,并且排列前4名的机构均来自美国和澳大利亚;国际上发文量超过10篇的作者中有2个来自美国,有3个来自澳大利亚,并且发文量前3名的作者中有2个来自澳大利亚。另外,高被引论文前10名中有4篇的作者来自美国,说明其在该领域具有较强的科研实力和较高的影响力。我国有关红树林碳汇效能研究的论文发文量逐年增加,在发文量前10名国家中排列第4,但总被引频次和篇均被引频次均较低。我国在国际排名前10位机构、发文量前10名作者和高被引论文前10篇中均占有一席之位,说明近年来我国在该领域发展迅速,科研实力不断增强,但在今后的发展中还需加强科研经费投入,引进高水平人才,加强国际合作,大力推动我国红树林碳汇的研究,提高我国在国际上的影响力。     

Forest soils and carbon sequestration

Soils in equilibrium with a natural forest ecosystem have high carbon (C) density. The ratio of soil:vegetation C density increases with latitude. Land use change, particularly conversion to agricultural ecosystems, depletes the soil C stock. Thus, degraded agricultural soils have lower soil organic carbon (SOC) stock than their potential capacity. Consequently, afforestation of agricultural soils and management of forest plantations can enhance SOC stock through C sequestration. The rate of SOC sequestration, and the magnitude and quality of soil C stock depend on the complex interaction between climate, soils, tree species and management, and chemical composition of the litter as determined by the dominant tree species. Increasing production of forest biomass per se may not necessarily increase the SOC stocks. Fire, natural or managed, is an important perturbation that can affect soil C stock for a long period after the event. The soil C stock can be greatly enhanced by a careful site preparation, adequate soil drainage, growing species with a high NPP, applying N and micronutrients (Fe) as fertilizers or biosolids, and conserving soil and water resources. Climate change may also stimulate forest growth by enhancing availability of mineral N and through the CO₂ fertilization effect, which may partly compensate release of soil C in response to warming. There are significant advances in measurement of soil C stock and fluxes, and scaling of C stock from pedon/plot scale to regional and national scales. Soil C sequestration in boreal and temperate forests may be an important strategy to ameliorate changes in atmospheric chemistry.     

Preparation of Magnetic Activated Carbon

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