青海森林固碳及其他生态系统功能的潜力和挑战--最终.doc

青海省森林植被固碳现状、潜力及其意义王长庭， 王根绪， 刘伟摘要：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。利用我国第三次 (19891993年) 至第六次 (20042008 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246 500 hm2 增加到2008年的355 000 hm2。（2）青海省4 次森林资源清查中森林植被整体碳储量分别是8 143 436.42 t 、9 115 234.11 t 、10 205 627.95 t 和11 182 642.22 t，总体呈上升的趋势。从1989年的8 143 436.42 t增加到2008年的11 182 642.22 t，增加了3 039 205.799 t，年均增加 (19a) 159 961.05 t，年均增长率1.68%，说明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柏木桦木杨树云杉，可见这几种森林植被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。关键词：森林生物量；森林碳储量；固碳现状；固碳潜力；青海省Carbon sequestration, potential and its importance by forest vegetation in Qinghai ProvinceAbstract: To evaluate forest carbon stock dynamics, carbon sequestration and carbon sink capacity of regional forest scientifically is of great importance to understand terrestrial ecosystem carbon cycle and carbon source and sink function. Based on the national forest inventory data from 1989 to 2008, the carbon storage of forests in Qinghai Province was estimated by the linear relationship between stand biomass and volume. The results showed that (1) the forest area increased 246 500 hm2 in 1989 to 355 000 hm2 in 2008. (2) the total carbon storage of forest vegetation in 19891993, 19941998, 19992003 and 20042008 was 8 143 436.42 t 、9 115 234.11 t 、10 205 627.95 t and 11 182 642.22 t, respectively, with an increasing trend in general. Forest carbon stock in Qinghai increased 3 039 205.799 t from 8 143 436.42 t in 1989 to 11 182 642.22 t in 2008 and by 1.68% annually during the study period，indicating that the forests in Qinghai Province play a role as a sink of atmospheric carbon dioxide, carbon sink and sequestration was strengthened with forest area increasing during the last 19 years. (3) Carbon sink increment of main forest type ranged as Cypress Betula Populus Picea, the results indicated that these several kinds of forest played an important role in carbon sink function in Qinghais forest vegetation. If the current forest in managed well, it would become a huge potential carbon sink in the future. Key words: Forest biomass; Forest carbon stock; Carbon sequestration status; Carbon sequestration potential; Qinghai province1. Introduction 哥本哈根气候大会昭示着气候变暖问题已严重威胁到人类的生存和发展（UNCCC，2009）。气候变暖与陆地碳循环动态及其反馈效应密切相关，森林作为大气CO2最大的陆地碳库，在陆地碳循环中占主导地位，其碳汇功能对碳收支平衡起着不可替代的作用（Nabuurs et al., 2003; Woodall et al., 2008; Woodbury et al., 2007）。有研究表明，森林植物在其生长过程中可通过同化作用吸收大气中的C02，以生物量的形式将其固定在植物体和土壤中，使森林成为陆地生态系统最重要的碳汇或碳库（Cials, 1995b）。全球的森林面积只占土地面积的27.6%，但森林植被碳贮量却占全球植被的77%，森林土壤的碳贮量约占全球土壤的39%；单位面积森林生态系统碳储量是农地的1.9- 5倍(Bousquet, 2000)。森林生态系统在全球碳循环中具有重要的意义, 主要表现在: (1)森林是陆地生态系统中最大的碳库，贮存了陆地生态系统总碳库的56%( Dixon et al., 1994); (2)森林单位面积的碳贮存密度很大，达到198Mg hm-2( Dixon et al., 1994), 森林的面积变化直接影响到陆地生态系统的碳源碳汇作用; (3)森林植被的碳积累速度快, 即森林固定大气CO2的速率大(Houghton et al., 2000)。为此森林生态系统的固碳措施, 包括造林、森林采伐和再造林, 已经被纳入到旨在减少全球大气CO2排放的京都议定书中。世界各国科学家都在不断探讨和估算全球和区域的森林生态系统的固碳能力。中国森林植被的固碳能力一直受到国际社会的高度关注，目前已经有不同的作者对中国森林植被的碳贮量(Fang et al., 2001; Wang et al., 2001; Zhao et al., 2004; Zhou et al., 1996)、固碳现状(Fang, 2000; Liu et al.,2000; Houghton et al., 1999; Houghton, 2003)和潜力(Zhang and Xu, 2003)进行了估算, 但这些研究大都基于1998年前的全国森林普查资料。In recent years，with increasing scientific and political interest in regional aspects of the global carbon cycle, there is a strong impetus to better understand the carbon balance of China (Houghton, 2007)。加之一系列新的林业举措, 如森林禁采和限采政策的推行和六大林业工程(天然林资源保护工程、退耕还林工程、三北长江流域等重点防护林建设工程、环北京地区防沙治沙工程、全国野生动植物保护及自然保护区建设工程和重点地区速生丰产用材林基地建设程)( Zhou, 2005)的展开, 对森林资源的开发强度有所减缓, 森林的面积逐步扩大。中国的森林覆盖率由1998年的16.55%增加到2003年的18.21% ( State Forestry Administration, 2003)。2009年9月22日，胡锦涛主席在联合国气候变化峰会上宣布，除了努力节约能源和提高能效，大力发展可再生能源和核能以及研发和推广气候友好技术外，中国将通过大范围植树造林来应对气候变化。在增加森林碳汇方面，他指出中国争取到2020年森林面积比2005年增加4000万hm2。森林蓄积量增加13亿 m3 (Liu et al., 2010)。这些变化都会影响到森林生态系统的碳源碳汇特征和固碳潜力。作为整个森林生态系统运行的能量基础和营养物质来源，森林生物量大小和变化是森林植被自身的生物学、生态学特征及其他自然因素与区域人类活动综合作用的表现，是度量森林生态系统结构和功能变化的重要指标之一，并已成为森林固碳能力的重要标志，以及评估森林碳收支的重要参数(Feng et al., 1999)。因此，准确估算区域森林的生物量对研究区域陆地生态系统的生产力、碳循环、全球气候变化具有十分重要的意义。我国大区域森林的生物量研究始于20世纪90年代末期 ，许多学者在这方面进行了研究，先后建立了主要树种的生物量测定相对生长方程，估算了它们的生物量与生产力，初步总结了全国不同类型森林的生物量与生产力及其格局（Liu et al., 2000; Zhou et al., 2000; Luo et al., 1998; Fang et al., 1996; Luo et al., 1999; Luo et al., 2002）。基于森林资源清查数据进行大区域森林生物量的估算一直是人们关注的焦点(Guang, 2007)，现已成为区域森林植物生物量和碳储量估测的发展趋势(Jiao and Hu, 2005)。近年来，国内较多学者基于区域性的森林资源清查资料，开展了不同区域范围内的森林生物量和碳储量研究工作(Cao et al., 2002; Yang and Guan, 2007; Wang and Wei, 2007; Yu et al., 2008; Zeng, 2005; Fan et al., 2008; Fang et al., 2007; Fang et al., 2002; Fang et al., 1996; Zhou et al., 2007; Wang et al., 2008; Huang et al., 2008Ye and She, 2010; Zhang et al., 2011)，为评价区域尺度的生态质量和研究我国森林生态系统的碳汇能力提供了重要参考。青海省至2007年已完成第7次森林资源清查，并积累了多期可比性强的清查数据，这为该区森林植被碳动态的研究提供了重要条件。笔者利用青海省第3、4、5、6次森林资源清查数据, 对全省森林植被碳储量动态变化、固碳潜力进行了初步的评述和对比分析, 旨在为区域碳循环研究积累基础资料，对于今后开展全省森林植被CDM（Clean Development Mechanism）碳汇功能评价和森林碳生态效益补偿机制的建立，同时也为全球变暖背景下制定减排增汇的相关区域环境决策提供参考。 Copenhagen Climate Summit makes it more obvious that climate warming has threatened the survival and development of human seriously(UNCCC，2009).Climate warming closely related to the terrestrial ecosystem carbon cycle dynamics and its feedback effect. As the largest carbon pool of carbon dioxide, forest holds a leading position in the terrestrial cycle and whose carbon sink function to carbon budget balance is irreplaceable( Nabuur et al.,2003;Woodall et al.,2008;Woodall et al.,2007).Researches have showed that forest plants can absorb C02 from the atmosphere by assimilation in the process of growing and fix it into frond and soil with the form of biomass so as to make forest be the most important carbon sink or carbon pool(Cials,1995b).The whole world forest area just accounted for 27.6% of the area of land,but the forest vegetation carbon storage accounted for 77% of the whole vegetation and the carbon stock of forest soil accounted for about 39% of the whole world soil;carbon storage of the elemental area forest ecosystem was1.9 to 5 times of the farmland(Bousquet,2000).Forest ecosystem plays an very important role in the whole world carbon cycle, mainly performs as follows:(1)forest wasthe largest carbon pool in the terrestrial ecosystem and stored 56% of the total carbon pool of terrestrial ecosystem (Dixon et al .,1994);(2)carbon storage density of forest elemental area was very large, reaching up to 198Mg hm-2 (Dixon et al.,1994),the change of forest area affects the carbon origion and sink function of terrestrial ecosystem directly;(3)the carbon deposition rate of forest vegetation was swift,that is to say,the forest can fix carbon dioxide with high rates（Houghton et al.,2000). Thus the fixing carbon measures,including afforest,forest cut and reafforest had been brought into Kyoto Protocol which aims at decreasing the emission of carbon dioxide. Scientists throughout the world are exploring and estimating the fixing carbon capacity of forest ecosystem of the whole world and area endlessly. Community of nations has been has great concern on the capacity of fixing carbon of forest vegetation in China, there has been so many different scholars have evaluated the carbon stock (Fang et al., 2001; Wang et al., 2001; Zhao et al., 2004; Zhou et al., 1996), carbon sequestratin status (Fang, 2000; Liu et al.,2000; Houghton et al., 1999; Houghton, 2003) and carbon sequestratin potential(Zhang and Xu, 2003) at present, but most of these researches all based on the nationwide forest general survey datas before 1998. In recent years，with increasing scientific and political interest in regional aspects of the global carbon cycle, there is a strong impetus to better understand the carbon balance of China (Houghton, 2007). Additionally, a series of new forestry measures, for example, the development of practice of prohibition and limitation of forest cutting, six major forestry projects, including Natural Forest Protection program, Conversion of Cropland into Forestland Program,Central Government in Beijing against Sand Project, Construction of the Three-North and Yangtze River Basin and other key Shelterbelt Project, National Wildlife and Nature Protection Construction Project and Key areas of fast Growing Timber Base Construction Process has decreased the exploitation intensity of forest resource in some extent and the area of forest enlarged gradually. Forest coverage in China increased 16.55% in 1998 to 18.21% in 2003 ( State Forestry Administration, 2003). President, Hu jintao,announced that China would face the climate change by large-scale afforestation except trying to save energy and improve energy efficiency, devote major efforts to developing renewable energy, nuclear power and research and popularize climate-friendly technique at the United Nations Summit on Climate Change on september 22，2009. On the aspect of increasing forest carbon sink, he Pointed out that China would strive for increasing forest area 400000000 hm2 and forest accumulationm3 (Liu et al., 2010) in 2020 than 2005. All these changes will have an influence on the feature of carbon source and sink and carbon sequestration potential of forest ecosystem. As energy foundation and nutrition substance source of operation of the whole forest ecosystem, the amount of forest biomass and change is the comprehensive representation of forest vegetation itself whose feature about biology and other natural causes and human activity and one of the important quotas to measure forest ecosystem structure and change of function, in addition, it has been a very important symbol of forest carbon sequestration capacity and parameter of estimating the forest budget (Feng et al., 1999). Therefore，to evaluate the biomass of regional forest truly is of great significance to research the productivity, carbon cycle and climate change throughout the world of terrestrial ecosystem. The large-scale forest biomass research in our country started in the late 1990s and many scholars have studied on it, moreover, they built biomass inventory relative growth equation of the major tree species one after another and evaluated biomass and productivity and briefly concluded the biomass and productivity of different kinds of forest and its arrangement（Liu et al., 2000; Zhou et al., 2000; Luo et al., 1998; Fang et al., 1996; Luo et al., 1999; Luo et al., 2002）. to evaluate the large-scale forest biomass based on the forest resource inventory data has always been attaching peoples attention (Guang, 2007) and now it has been the development trend of regional forest plants biomass and carbon stock caculationn (Jiao and Hu, 2005). In recent years, based on regional forest resource inventory data, many domestic scholars started to work to research forest biomass and carbon storage in different areas (Cao et al., 2002; Yang and Guan, 2007; Wang and Wei, 2007; Yu et al., 2008; Zeng, 2005; Fan et al., 2008; Fang et al., 2007; Fang et al., 2002; Fang et al., 1996; Zhou et al., 2007; Wang et al., 2008; Huang et al., 2008Ye and She, 2010;Zhang et al., 2011)，provided with reference to appraise ecology quality of regional scale and study carbon sink capacity of forest ecosystem of our country. Qinghai had accomplished the seventh forest resource inventory until 2007 and accumulated inventories data which was more authentic than any other inventory data in different period, offering a key term to research forest vegetation carbon dynamics for Qinghai province. Employed the third, fourth, fifth, sixth forest resource inventory data, the author briefly calculated and relatively analysed the change of forest vegetation carbon stock dynamics and carbon sequestration potential in Qinghai province, aiming at accumulating basic data to study regional carbon cycle and evaluating the whole province carbon storage of forest vegetation CDM（Clean Development Mechanism）in the future and setting compensation mechanism of forest carbon ecological benefits, meanwhile, providing reference to take measures to reduce emission and increase sink under the background of global warming.2. 材料与方法Materials and Methods2.1 区域概况Regional Overview青海省位于青藏高原的东北部（31393919N，89351034E），东西长约1200 km，南北宽约800 km，总土地面积超过72万km2，占全国总土地面积的13.15。燕山运动奠定地形复杂多样，高山high mountain、丘陵/knap、河谷/ralley、盆地basin交错分布，平均海拔3 000 m以上，属典型高原大陆性气候plateau continental climate。年均气温3.76.0 ，年日照2 3403 550 h，年降水量l6.7776.1 mm(大部分400 mm以下)，年蒸发量1 1184 3 5362 mm (Dong, 2009)。森林植被分布于东经96以东，主要江河及其支流的河谷两岸，森林分布海拔大多在25004200 km，以寒温带常绿针叶林亚型为主，其次为落叶林植被型(多为原始林破坏后的次生类型)。植被地域上跨青藏高原、温带荒漠和温带草原3个植被区，具有高寒和旱生的特点，以寒温性常绿针叶林为主,常见的针叶树种有云杉Picea、圆柏等，阔叶树种 有杨树 Populus、桦木等 Betula，灌木有金露梅 L. 、杜鹃、锦鸡儿、高山柳等(Zhang et al., 2007; Dong, 2009)。 Qinghai province lies in the northeast of Qinghai-tibet plateau (31393919N，89351034E）,about 1200 kilometers long from east to west ,800 kilometers wide from south to north. The total land area of Qinghai province more than 72 square kilometres which accounts for the 13.15% of the whole China. Yangshan movement lay the complex and varied terrain that high mountain, hill, river ralley and basin crisscross distribution , its a typical kind of plateau continental climate with an average altitude of over 3000 meters and annual temperature of minus 3.7 to 6.0 ,in 2 3403 550 hours of sunshine , l6.7776.1 mm rainfall(most under 400mm), evaporation capacity of 1 1184 3 5362 mm (Dong, 2009). Forest vegetation distributes in the east longitude 96, valley cross-straits of major rivers and their branches; most of forests distribution with an altitude of over 25004200 km and frigid temperate evergreen coniferous subtype base, followed by deciduous vegetation(mostly secondary after the destruction of the original forest type). The vegetation With frigid temperate evergreen coniferous base which extends three vegetation zones ,Qinghai-tibet plateau, temperate deserts and grasslands and which is highly cold and extremely dry, the commonly seen conifer trees are picea, juniper etc, the broadleaf trees are populus and betula and the bushes are potentilla fruticosa L.,cuckoo, golden pheasant children, mountain willow and so on(Zhang et al., 2007; Dong, 2009). 2.2 研究资料Research Data本研究所使用的森林资源数据是19891993年、19941998、19992003 和 20042008年4次青海省森林资源清查资料。The forest resource data used in this research is from the year 1989 to 1993，1994 to 1998，1999 to 2003 and 2004 to 2008 four forest resources inventories data in Qinghai province.2.3 研究方法Research Methods2.3.1 森林生物量测定Inventory of Forest Biomass 由于森林资源清查资料提供了(林分forest stands)各优势树种各龄组的面积和蓄积。森林蓄积量是森林生长的立地条件、气候条件和森林年龄及其他各因素的综合反映,大量森林实测生物量与蓄积量的关系研究表明,在不同林分类型中二者均存在着良好的回归关系(Wang et al.,2001; Wang and Wei, 2007; Yu et al.,2008)，因而材积源生物量法弥补了平均生物量法所带来的一些人为差异,基本上能很好地体现实际情况(Liu et al.,2000) . 本文采用Fang et al (1996、1998 )、Liu et al (2000)所建立的各个林分生物量与蓄积量之间的回归关系(表1)，来估测青海省森林生物量。 As forest resource forest inventory data provided that the area and volume of each priority species biomass and groups of age of forest stands. Forest volume is a combination of reactions of the ground，climate，forest age and other factors for the growing of forest, research on the relationship between a great deal of forest biomass and volume shows that there is a favorable regression relationship between biomass and volume with different forest stands (Wang et al.,2001; Wang and Wei, 2007; Yu et al.,2008)，therefore volume-derived method offsetted the factititious distinctions caused by method of average biomass and can basically well reflect the reality .To evaluate the the forest biomass in Qinghai province, we use the regression equation between biomass and volume with different forests built by Fang et al (1996、1998 )、Liu et al (2000)(Table 1) in this text.表1 不同林分类型生物量与蓄积量回归方程Table 1 The regression equation (RQ) between biomass and volume with different forests林分类型Type of forest stands生物量（B）-蓄积量（V）回归方程RG of biomass-volume样本数Number of sample相关系数Correlation coefficient落叶松 LarixB=0.9671V+5.7598130.99云杉 PiceaB=0.4642V+47.499190.99冷杉 AbiesB=0.4642V+47.499190.99油松 P. tabulaeformisB=0.7554V+5.0928900.98华山松 P. armandiB=0.5856V+18.7435100.95柏木 CypressB=0.6129V+26.1451190.98栎类 QuercusB=1.3288V3.899961.00杨树 PopulusB=0.4754V+30.6034160.93桦木 BetulaB=0.9644V+0.848560.98软阔类 SoftwoodB=1.1595V1.5306*500.93*Luo et al (1998) 2.3.2 森林植被碳储量计算 Count of Forest Vegetation Carbon Stock 森林植被碳储量由乔木层、灌木层、草本层和枯枝落叶层的组成。森林植被碳储量为森林生物量乘以转换系数，本文采用目前国际上常用的转换系数0.5(即每克干物质的碳储量)（Murillo, 1997; Brown et al., 1999）；本文计算的森林植被碳储量指乔木层碳储量，未包括灌木层、草本层和枯枝落叶层的碳储量。另外，本研究中的碳增汇量是指生物量增加部分的碳汇储量，碳密度则是碳储量与森林面积的比值。Forest vegetation carbon stock is the result that biomass multiplied by the conversion factor which made of the carbon stock of tree layer, shrub layer, herbaceous layer and litter layer. We use the conversion factor 0.5 which commonly used by the international people in this text(namely the carbon storage of per gram dry matter)( Murllo,1997;Brown et.1999);the forest vegetation carbon storage counted n this text refers to the carbon storage of the tree layer instead of the carbon stock of shrub layer, herbaceous layer and litter layer. In addition, the carbon sink increment in the study refers to the increased part carbon sink storage of the biomass and the carbon density refers to the ratio between carbon storage and forest area.3. 结果与分析Results and Analysis3.1 各时期的森林植被碳储量Forest Vegetation Carbon Stock in Different Period 青海森林植被碳储量从1989年的8 143 436.421 t增加到2008年的11 182 642.22 t (表2)，增加了3 039 205.799 t，年均增加 (19a) 159961.05 t，年均增长率1.68% 。从1989年到1993年的5a five years ?中，森林植被碳储量增加971 797.693 t；从1994年到1998年的5a中，森林植被