作 者 ：桑卫国, 马克平, 陈灵芝
期 刊 ：植物生态学报 2002年 26卷 5期 页码：543-548
Keywords:Deciduous broad-leaved forest, Carbon cycle,
摘 要 ：森林生态系统碳循环过程与大气中二氧化碳含量有密切的关系，直接影响着大气成分的组成，进而对全球气候变化有重要影响。以我国暖温带落叶阔叶林生态系统近10年的定位研究为基础，初步建立了该类生态系统碳循环数值模式。结果表明：暖温带落叶阔叶林典型生态系统每年从外界主要是大气中吸收的碳是10.3 t·hm-2·a-1，植物呼吸释放到大气中的碳通量为5.5 t·hm-2·a-1。森林植物干物质积存的碳量为4.8 t·hm-2·a-1，通过凋落物分解释放到大气中的碳通量为2.46 t·hm-2·a-1。森林同化的碳绝大部分以活生物呼吸和凋落物分解的形式释放到大气中去了，存留在活生物体和凋落物中的很少。通过对碳现存量的研究发现，所研究的森林生态系统碳现存量为165.05 t·hm-2，其中活生物体碳现存量为61.2 t·hm-2，死生物体碳现存量为104.05 t·hm-2 (包括土壤中碳)，土壤碳现存量为96 t·hm-2。土壤碳储量占总碳储量的58%，土壤是该地区森林生态系统主要的碳库，森林生态系统土壤中碳储量的变化必然引起整个区域碳储量整体动态的变化。
Abstract:Carbon is the main element of biological material, especially of plant matter. The carbon content accounts for half of the total dry biomass, so the biosphere is a big carbon pool and the carbon content of terrestrial ecosystems has significant effects on carbon biogeochemical cycling. When the carbon content of the biosphere decreases, most of the carbon is released to the atmosphere and causes the concentration of carbon dioxide in the atmosphere to increase greatly. CO2 is a green house gas; increased atmospheric concentrations will cause increased warming of the climate. In recent years, with increasing usage of fossil fuel and the destruction of natural ecosystems, the increasing release of CO2 from those processes caused the temperature of the earth’s surface to rise and then gradually level at a higher standard. The carbon cycling in forest ecosystems is closely related to CO2 concentration in atmosphere, has an obvious effect on composition of atmospheric elements, and so can influence global climate change. This study focused on the carbon distribution among each component of a typical temperate forest ecosystem of the Beijing area, China. The forest belongs to the warm temperate zone, with a continental monsoon climate which shows clear seasonal periods, dry and cold in winter, warm and humid in summer. The mean annual temperature averages 4.8℃, -10.1 ℃ in January and 18.3 ℃ in July. The annual precipitation amounts to 611.9 mm, 78 percent occurring in June, July and August. The soil is dominated by mountain brown earth. At the research site, the forest is dominated by Quercus liaotungensis, and also includes Betula dahurica, Acer mono, Populus davidiana, Betula platyphylla, Fraxinus rhynchophylla and other related species.We attempt to set up a numerical estimation of forest carbon cycling that will provide parameters of a future computer model. The carbon cycle includes many processes of a forest ecosystem, and so it is difficult to accurately estimate the amount of forest ecosystem carbon. A numerical model of the carbon cycle in this forest ecosystem was established based on studies of this warm temperate deciduous broad-leaved forest ecosystem over 10 years. The data we used in this paper are forest biomass, productivity, biogeochemical cycle, and related published results. We processed, analyzed, integrated, and transformed all the data. Finally we used a comparative method to get more insight on the carbon cycle among different forest ecosystems.Our results showed that a typical forest ecosystem in warm temperate region absorbed 10.3 t·hm-2·a-1 carbon from the atmosphere through photosynthesis. Carbon released to the atmosphere from plant respiration was 5.5 t·hm-2·a-1, with 4.8 t·hm-2·a-1 accumulated in dry plant biomass, and 2.46 t·hm-2·a-1 emitted to the atmosphere by decomposing plant litter. Most carbon assimilated by forests was respired and decomposed to the atmosphere, with little retention in living or dead biomass. Investigation on C storage of warm temperate forests found that carbon-standing amount was 165.05 t·hm-2, with 61.2 t·hm-2 in living biomass, 104.05 t·hm-2 in dead biomass (including soil carbon), and 96 t·hm-2 stored in the soil. The soil C storage in the forest studied accounted for 58% of total forest carbon, and therefore we concluded that carbon in the forest soil is the main storage pool of the forest. C storage change in the forest soil will definitely affect C change of forests in the entire region greatly.