中国亚热带森林土壤呼吸的基本特点

中国亚热带森林在全球森林生态系统中具有独特的植被类型及结构,长期受人类活动干扰(毁林、造林等),森林土壤碳呼吸特征不明确,较难准确估算土壤碳的分配情况.分析了我国亚热带森林土壤呼吸在不同森林类型、不同退化和恢复演替阶段,以及造林再造林等的影响条件下的变化规律.结果表明:我国亚热带区域中的天然林的土壤呼吸通常表现为针叶林(如马尾松林)<松阔或针阔混交林<季风常绿阔林;马尾松与杉木人工林广布中国亚热带地区,两种林分的CO2年通量相当,中龄林较之幼龄林,土壤有机碳库呈现减少趋势;不同研究区域相同林分的土壤呼吸效率初步表现为南强北弱;我国亚热带森林的土壤呼吸通量与世界其他地区的热带森林土壤呼吸通量相差无己,其释放的碳量对全球碳通量的影响应加以重视.

Elementary Characteristics of Soil Respiration in Chinese Subtropical Forests

Chinese subtropical forests, which have unique plant type and construction in global forest sys- tem, are disturbed by human activities, such as deforestation and forestation. It is difficult to estimate soil carbon distribution of Chinese forestry accurately for the characteristics of carbon soil respiration. To under- stand the great potential role of SR of Chinese subtropical forests playing in global forest soil carbon pool, the trends of SR fluctuation under different circumstances of forest types, different succession and recover stages, forestation and deforestation, and so on were analyzed. The findings show that first, the soil in nee- die-leaved plants（such as masson pine） covered area can respire less carbon than that of mixed broadleaf- conifer forests. The soil covered by broad-leaf evergreen forests has the highest respiration ability;second, Chinese red pine and man-made fir forests are the main species grown widely in Chinese subtropical zone. These two types of forests contain equal fluxes of C02 and the fluxes of SR of sapling forest are higher than that of middle-aged forests,because soil organic carbon mass decrease;third,the fluxes of the same forest stands in different areas are different from one another and southern part is higher than northern part;last, annual mean fluxes of SR in Chinese subtropical forest are no less than that of tropical forest or tropical lowland forest in the other world areas. The influence of efflux per year emitted from Chinese subtropical forests on the world flux of C02 cannot be ignored.