广西罗城不同土地利用方式与林地碳储量的变化研究

【作者】 陶玉华；

【导师】 冯金朝；

【作者基本信息】 中央民族大学 ， 民族生态学， 2012， 博士

【摘要】 CO2浓度增加引起的温室效应和气候变暖正威胁着全球经济、社会、生态环境和人类生存,气候变化适应与减缓成为各国政府和科学家关注的热点问题。森林作为陆地最大的碳库,其碳储量分配的动态变化影响着全球碳循环的平衡,而土地利用方式变化对生态系统碳储量的分配具有重要的影响,仅次于化石燃料燃烧使大气CO2浓度增加的最主要的人为活动。评价不同土地利用方式下生态系统的碳汇贡献率不仅可以为生态系统碳循环的研究提供基础资料,而且对制定森林生态系统的管理策略和森林的可持续发展都具有重要的意义。本文研究和评价了人工林、神山和荒山三种不同的土地利用方式下其生态系统碳汇的贡献率及其影响因素,探讨少数民族的生态伦理思想在保护森林、维持生态平衡和增加碳汇方面的作用,对传承和弘扬少数民族传统文化和恢复生态都具有重要的意义。本研究以广西罗城仫佬族自治县人工林、神山和荒山为研究对象,通过设立样地对生态系统各组分的生物量、含碳率和碳储量的分配进行了深入的分析和讨论,同时通过访谈形式对神山进行了民族志调查,主要结论如下：1.植被组成与结构样地调查共记录人工林林下植被物种数为64种,隶属于42科63属；其中桉树(Eucalyptus sp.)人工林植物有37种,马尾松(Pinus massoniana)人工林植物有34种,杉木(Cunninghamia lanceolata)人工林植物有34种。神山植被物种数为35,隶属于20科34属；荒山植被物种数为32,隶属于21科32属。植被丰富度计算结果表明,荒山最大,其次为神山和马尾松人工林。三种类型的生态系统人工林植被的垂直结构较为明显,从上到下依次表现为：乔木冠层、灌木层、草本层和地被层。人工林植被生活型的构成以高位芽为主。2.人工林生态系统的碳储量广西罗城马尾松、杉木和桉树人工林生态系统的碳储量分别为135.61t·hm-2、144.3t·hm-2和87.54t·hm-2。三种人工林生态系统碳储量的平均值均低于我国森林生态系统的平均碳储量(258.83t·hm~-2)乔木层是人工林生态系统中重要的碳库。广西罗城县马尾松、杉木和桉树人工林的乔木层碳储量均表现为随着林龄的增加而增大的趋势。其中马尾松林乔木层的碳储量为0.45～106.47t·hm-2,杉木林为0.18～87.44t·hm-2,桉树林为2.68～31.62t·hm-2。乔木层碳储量大小依次为马尾松林>杉木林>桉树林。除了幼龄林乔木层的碳储量较低外,其他林龄的乔木层在人工林生态系统总碳储量中的贡献率较高,占其生态系统总碳储量的比例为28.22%～62.43%。马尾松、杉木和桉树人工林林下植被的碳储量分别为0.39～1.67t·hm-2、1.34~3.14t·hm-2和0.83～3.93t·hm-2,占其生态系统总碳储量的0.23%-3.73%。马尾松、杉木和桉树人工林枯落物的碳储量分别为1.5~2.55t·hm-2、1.95~16.04t·hm-2和0.85～2.36t·hm~-2,占其总碳储量的0.85%-10.86%。在林下植被层和地被层中,杉木枯落物碳储量最高,马尾松林下植被碳储量最低。与乔木层和土壤相比较,林下植被和枯落物的碳汇贡献率较小。马尾松、杉木和桉树人工林的土壤碳储量分别为74.13t·hm-286.48t·hm-2和62.95t·hm-2,占其生态系统总碳储量的60.6%-76.96%,在0-60cm深度范围内均随着土壤土层深度的增加而降低,三者0-20cm土层的土壤碳储量占其土壤总碳储量的41.24%～62.54%,可见土壤碳储量是人工林生态系统的重要碳库,表层土碳储量是土壤碳库的重要组成部分。马尾松、杉木和桉树人工林土壤碳储量的比例均表现为随着林龄的增加而减小的趋势。3.神山生态系统的碳储量广西罗城神山生态系统的总碳储量为137.06t·hm~-2。其中乔木层的碳储量为35.41t·hm-2,占生态系统碳储量的25.83%；灌草和枯落物碳储量分别为2.81t·hm-2和2.24t·hm-2,占总生态系统碳储量的2.05%和1.63%；0-20cm土层土壤碳储量为41.01～88.92t·hm-2,20～40cm土壤碳储量为33.19～47.4t·hm-2,土壤总碳储量占其生态系统碳储量的70.48%。神山生态系统土壤和乔木层是神山森林生态系统碳储量主要的碳库,其中土壤碳储量是乔木层的2.73倍。4.荒山生态系统的碳储量广西罗城荒山生态系统包括荒山灌草地生态系统和荒山草地生态系统,其中荒山灌草地生态系统的总碳储量为126.53t·hm-2,荒山草地生态系统为60.93t·hm-2。荒山灌草地灌草和枯落物的碳储量分别为8.43和0.32t·hm~-2,草地为1.86和0.44t·hm~-2。荒山灌草地和荒山草地的土壤碳储量分别为117.78和58.63t·hm-2,占其生态系统碳储量的93.08%和96.23%。荒山生态系统的碳储量主要集中在土壤,灌草地和草地土壤碳储量分别是其地上植被碳储量的13.15和25.49倍。5.人工林、神山和荒山生态系统碳储量的比较马尾松和杉木人工林乔木层的碳储量分别高于神山,神山和荒山灌草和枯落物碳储量则分别高于马尾松、杉木和桉树人工林,神山土壤碳储量高于荒山、马尾松和桉树人工林,但低于杉木林。杉木和马尾松人工林多数林分(杉木中龄林、近熟林、成熟林、过熟林和马尾松近熟林)生态系统的碳储量均高于神山,由于其幼龄林的存在,马尾松人工林生态系统的平均碳储量略低于神山。马尾松和杉木人工林生态系统碳储量均高于荒山。桉树人工林生态系统碳储量分别低于荒山和神山,归因于其树龄小导致的乔木层碳储量低。6.神山保护的民族生态学调查通过查阅文献、半结构访谈和关键人物访谈,结果表明广西罗城四堡村的村民通过长期形成的传统文化,万物有灵的朴素意识来保护神山的自然植被,使处于喀斯特地貌环境下的神山森林生态系统得以很好的保存至今,这对村社水平的森林植被保护具有重要参考价值和研究意义。同时国家政策也影响着神山森林生态系统的发展,采取国家生态补偿机制和与气候变化相关的碳汇项目与村民保护神山的传统文化结合起来将会是保护神山森林生态系统的同时又使村民受益的好方法。更多还原

【Abstract】 The potential effects of global warming are threatening the global economy, society, the ecological environment and even human survival. These threats have caused governments and scientists to examine and research as a top priority methods and policies regarding the adaptation and mitigation of climate change. Since forests contain the world’s largest terrestrial carbon pool, activities that change the carbon dynamics of forests can affects the balance of the global carbon cycle. Land use change is one such activity that has great potential to change the carbon storage, sinks and sources of these ecosystems. Subsequently, terrestrial carbon emissions resulting from land use change has the potential to be only second to the carbon emitted from the combustion of fossil fuels. Therefore, evaluating ecosystem carbon stocks and dynamics within the context of different land use patterns not only provides basic data for ecosystem carbon cycle research, but also important knowledge necessary for development of strategies for forest ecosystem management and sustainable forestry.The carbon storage contribution of forest ecosystems in plantations, Karst holly hill and barren hill forests, and factors influencing this storage were studied in this dissertation. Also studying the ecological ethics of minority groups in regard to forest protection, and maintaining ecological balance and sequestered carbon is important in regard to future land use changes. The status of their traditional cultures and land inheritance in the future has the potential to impact future land use. Accordingly, a summary of the main conclusions of this research are as follows:1. The Composition and structure of vegetation measured in this studyA total number of66species, belonging to21families and representing35genera, were recorded in the plantation forests, with37species of eucalyptus (Eucalyptus sp.),34species of Masson pine (Pinus massoniana) and34Species of Chinese fir (Cunninghamia lanceolata). In the Karst holly hill ecosystem a total of35species belonging to20families and representing34genera were recorded. This was comparable to the Karst barren hill ecosystem where a total of32species, belonging to21families and representing32genera, were recorded. The species richness of Karst barren hill vegetation was the highest, followed by the Karst holly ecosystem and the Masson pine plantation in descending order.Evident vertical structure in three plantation ecosystems are as follows from top to botton:tree layer, shrub, herb and litter. Macrophanerophytes dominated the vegetation communities in all three ecosystems.2. The carbon storage of plantation ecosystemThe carbon storage of Masson pine, Chinese fir and eucalyptus plantation ecosystems are135.61t·hm-2,144.3t·hm-2and87.54t·hm-2respectively. The mean carbon stocks in these ecosystems are lower than average carbon stock reported for all of China’s forest ecosystems (258.83t·hm-2).Tree layers were the important carbon pools in plantation ecosystems, the carbon stored in the tree layer of these plantations ranged from0.45~106.47t·hm-2,0.18~87.44t·hm-2, and2.68~31.62t·hm-2for Masson pine, Chinese fir, and eucalyptus, respectively, and increased with age. The average tree carbon storage of these plantations displayed a relationship of Masson pine> Chinese fir> eucalyptus. Except for young plantations, the tree carbon stocks contribute a significant portion to the total ecosystem, accounting for28.22%-62.43%of total ecosystem carbon storage.The understory carbon storage of Masson pine, Chinese fir and eucalyptus ranged from0.39~1.67t·hm-2,1.34~3.14t·hm-2and0.83~3.93t·hm-2respectively, accounting for0.23%-3.73%of total ecosystem carbon. The litter carbon stocks of Masson pine, Chinese fir and eucalyptus ranged from1.5~2.55t·hm-2,1.95~16.04t·hm-2and0.85~2.36t·hm-2respectively, accounting for0.85%~10.86%of the total ecosystem carbon.The soil carbon storage of Masson pine, Chinese fir and eucalyptus plantations are74.13,86.48and62.95t·hm-2respectively, accounting for60.6%~76.96%of total ecosystem carbon storage. The soil carbon sequestered within0-60cm depth decreases as soil depth increases. Carbon sequestered within0-20cm depth accounts for41.24%-62.54%of total soil carbon, and contributes the most to the total soil carbon pool. The carbon stored in the soil component of these plantation forests accounts for the highest carbon pool within these ecosystems. The total soil carbon stocks in all plantations decreases as plantations become older.3. The carbon storage of Karst holly hill ecosystemIt was determined that the total carbon stock within the Karst holly hill ecosystem was137.06t·hm-2. The tree carbon storage was35.41t·hm-2, accounting for25.83%of total ecosystem carbon. The carbon stored in the understory and litter layers is2.81t·hm-2and2.24t·hm-2, accounting for2.05%and1.63%of total ecosystem carbon, respectively. The carbon storage within the soil layers at depths of0-20cm and20-40cm ranged from41.01~88.92t·hm-2and33.19~47.4t·hm-2, respectively. The total soil carbon storage accounted for70.48%of total Karst holly hill ecosystem. The carbon stored in the tree and soil layers combined comprised the majority of the carbon stored in Karst holly hill ecosystem. The soil carbon layer contained2.73times more carbon than what was found in the tree layer.4. The carbon storage of Karst barren hillThe Karst barren hill vegetation was divided into two successional stages for the purpose of this study, represented by the herb community and the herb-shrub community. Each stage was separated into three layers for carbon analysis-the vegetation layer, the litter layer, and the soil layer. The total ecosystem carbon storage within the herb-shrub community was determined to be126.53t·hm-2, compared to60.93t·hm-2found in the herb community.Within the herb community, the carbon stock in the vegetation and litter layers was determined to be1.86t·hm-2and0.44t·hm-2, respectively. The carbon stock in the vegetation and litter layers within the herb-shrub community were determined to be8.43t·hm-2and0.32t·hm-2, respectively. The soil carbon stocks in the herb-shrub community and the herb community are117.78t·hm-2and58.63t·hm-2, accounting for 93.08%and96.23%of the total carbon within each of ecosystem, respectively. The carbon stored in the soil accounted for the majority of the carbon stock in the barren hill ecosystem.5. The comparsion of ecosystem of carbon storage in plantation, Karst holly hill and Karst barren hillThe amount of tree carbon stored in Masson pine and Chinese fir plantations was higher than the tree carbon stored in the Karst holly hill forests, with Masson pine forests displaying the highest of the three forests. However, the carbon stored in the vegetation and litter layers of the Karst holly hill and barren hill ecosystems was found to be higher than the understory layers in all the plantation forests. The carbon stored in the soil of the Karst holly hill was higher than that of the barren hill ecosystem, and the Masson pine and eucalyptus plantations, respectively, but lower than Chinese fir. The total carbon stocks found in middle-aged to over-mature Chinese fir and middle-aged to near mature Masson pine plantations were higher than the total carbon stocks found in the Karst holly hill ecosystem. The average value of carbon stored in the Masson pine ecosystem is lower than carbon found in the Karst holly hill ecosystem due to the number of young Masson pine plantations that were sampled. The total eucalyptus ecosystem carbon stocks were lower than what was found in the Karst holly hill and barren hill ecosystems due to the fact that young eucalyptus plantations were sampled in this study.6. Ethnography of protection of holly hillThrough literature review, semi-structured and key informant interviews, this study revealed that the traditional culture of animism has been formed in Sibao village over a long period of time. During this long period of time the vegetation of Karst holly hill ecosystem was well protected under their simple ecological ethic in this harsh Karst environment. This has played a significant role in protecting the vegetation of this ecosystem at the village level. Meanwhile, national policy has also affected the development of the Karst holly hill forest ecosystem. The combination of a national ecological compensation mechanisms and development of carbon sequestration projects to mitigate climate change will provide a better way to not only protect the Karst ecosystems but also improve living conditions of local villagers.更多还原