亚热带常绿阔叶林碳汇转移机制与时空分异规律

The carbon sequestration function of forest ecosystem plays an important role in slowing global climate warming. It didn't segment research different natural zones forest ecosystems on forest ecosystem carbon sequestration. The key scientific issues of temporal-spatial differentiation law，main impact factors and transfer mechanism of forest vegetation and soil carbon sinks will be studied by taking the typical subtropical evergreen broad-leaved forests as the object of study. On the basis of sample-plot inventory, the main impact factors of forest vegetation and soil carbon sequestration of subtropical evergreen broad-leaved forests will be will explained, and the carbon partition coefficient and carbon turnover time of forest vegetation and soil will be determined by the observation and analysis on habitat factors, vegetation biomass, soil physical and chemical nature of subtropical evergreen broad-leaved forests (Castanopissclerophylla forest、Cyclobalanopsis glauca forest、Schima superba forest) in forest ecosystem research observation station of Jiangxi Dagang mountain, Jinggangshan and Qianyanzhou. Then, it will reveal the carbon microcirculation process of subtropical evergreen broad-leaved forests and the carbon transfer mechanism between forest vegetation and forest soil by application related theory of forestry, soil science and ecology. The carbon sequestration scale of subtropical evergreen broad-leaved forests vegetation and soil in Jiangxi Province will be scientific estimated through integrated use the combining method of remote sensing, mathematical model and ground survey. The temporal-spatial distribution characteristics and differences discipline of subtropical evergreen broad-leaved forests carbon sequestration will be also analyzed. It may provide the necessary scientific basis for enhancing the carbon sequestration potential of subtropical forest ecosystem.

森林生态系统碳汇功能在减缓全球气候变暖中起着重要作用。本项目以江西省典型的亚热带常绿阔叶林为研究对象，针对森林植被与土壤碳汇的时空分异规律、影响因子及转移机制等科学问题开展科学研究。通过样地调查，对江西大岗山、井冈山、千烟洲等森林生态系统观测研究站的常绿阔叶林(苦槠栲林、青冈栎林、木荷林)进行样地生境因子、植被生物量、土壤理化性质观测分析，阐释亚热带常绿阔叶林碳汇的主要影响因子，分析森林植被与土壤碳分配系数和碳周转时间，应用林学、土壤学、生态学等学科领域的相关基础理论，揭示亚热带常绿阔叶林碳微循环过程及森林植被与土壤间碳转移机制。综合运用遥感、数学模型、地面调查相结合的方法，科学计量江西省亚热带常绿阔叶林植被与土壤碳汇规模，并分析亚热带常绿阔林碳汇时空分布特征与差异规律,为增强亚热带森林生态系统碳汇潜力提供必要的科学基础。

常绿阔叶林具有强大的碳汇功能，在维持碳循环平衡方面具有重要的作用。因此，研究区域亚热带常绿阔叶林碳汇的规模大小、时空格局、影响因子非常必要。.本项目通过江西省大岗山、井冈山、九连山三个自然保护区内亚热带常绿阔叶林(苦槠栲林、青冈栎林、木荷林) 样地调查，测算江西省亚热带常绿阔叶林碳汇规模，并阐释碳汇能力的主要影响因子；通过建立植被指数遥感估算模型，估算其植被和土壤碳储量与碳密度，分析其时间动态变化；根据标准木各器官和土壤各土层有机碳含量分布，结合植被层和土壤层的碳储量与碳密度，综合分析其空间格局和碳转移机制。.研究表明：(1) 江西省亚热带常绿阔叶林植被碳密度与经度有显著相关性；植被碳密度不受纬度的影响；土壤碳密度与纬度有一定相关性；土壤碳密度与坡度有相关性；植被碳储量与林龄和植被层具有显著的相关性；植被和土壤的碳密度随气温的上升而增加；植被的碳密度随降雨量、日照时长的增加而增加；而土壤碳密度不受降雨量和日照时长的影响。(2) 1985-2015年，江西省亚热带常绿阔叶林植被和土壤的碳储量与碳密度总体呈增加趋势，植被和土壤碳储量分别由1985年的0.1254GtC、0.3820GtC增加到2015年的 0.2092GtC、0.5474 GtC，植被和土壤碳密度分别由1985年的63.071t/hm2、185.99t/hm2增加到2015年的76.31 t/hm2、199.69 t/hm2；赣西和赣东地区植被碳储量相对较高，赣中地区碳储量较低。(3)各树种器官有机碳含量均为叶>枝>干>根；土壤有机碳含量随着土层深度的增加而降低；江西省亚热带常绿阔叶林植被和土壤碳密度平均分别为84.31t/hm2、190.84 t/hm2；其中乔木层(78.96t/hm2)>灌木层(2.34t/hm2)>凋落层(1.97t/hm2 )>草本层(1.04t/hm2)；各土壤层碳密度分别为40.19t/hm2、29.78t/hm2、23.29t/hm2、40.06 t/hm2、57.53 t/hm2；(4)有机碳以净初级生产力（NPP）形式进入森林生态系统的地上植被层生物量碳库，同时部分以枯落物形式周转到 DOM 碳库，通过分解释放、采伐移除后存留在森林生态系统。.项目的研究结果可增强对不同自然地带森林生态系统结构功能的理解和认识，可为亚热带常绿阔叶林增强碳汇潜力提供必要的科学基础。