长白山四种林分土壤CO_2释放通量的研究

Soil CO_2 flux in several typical forests of Mt.Changbai.

对长白山地区 4种典型林分下土壤释放CO2 通量的研究表明 ,在较短的时间尺度上 ,4种林型在CO2 释放通量上有显著的差别 ,各林型CO2 通量的释放表现出明显的空间异质性 ,其释放顺序为 :山杨白桦混交林 >原始阔叶红松林 >白桦林 >山杨林 ,其中山杨白桦混交林对CO2 释放的贡献最大 ,而山杨林最小。 4种林分土壤CO2 通量的全日变化过程并不一致 ,除山杨白桦混交林和气温有较一致性的规律 ,呈较明显的单峰型外 ,其余并无明显的变化规律。凋落物对林地CO2 释放通量的变化有显著的影响 ,有凋落物覆盖的林地土壤CO2 释放量明显大于无凋落物覆盖的林地 ,其平均通量为 2 6 2 86～ 5 5 6 5 5mgC·m-2 ·h-1,而无凋落物覆盖林地土壤CO2 的平均通量为 2 0 5 85～ 395 6 9mg·m-2 ·h-1。凋落物排放CO2 量占林地总排放量的14 %～ 30 % ,并且改变了林地CO2 释放通量大小的排序。

The soil CO 2 flux of four temperate forest types was studied in Mt.Changbai. The soil CO 2 flux in the four typical forests was significantly different at short time scale. The released CO 2 flux of the four typical forest indicated obvious spatial heterogeneity. The rate of released CO 2 flux was the highest in Populus-Betula mixed forest and the lowest in populus forest. The sequence was: Populus-Betula mixed forest > broad leaved-Korean pine forest > Betula forest > Populus forest. Daily course of soil CO 2 flux was very different in the four forest types. Except for Populus-Betula mixed forest, in which the changes of CO 2 flux exhibited a single peak and showed relative consistency with changes of temperature, there were no regular changes of CO 2 flux in other forest types. The litter influenced the CO 2 flux significantly in each forest type. The CO 2 flux in the forest where soil was covered with litter was higher than that with out litter. The average value was 262.86～556.55 mgC·m -2·h -1 in the forests with the litter and 205.85～395.69 mg·m -2·h -1 in the forests without litter. The contribution of litter to total soil CO 2 flux was 14 %to 30%.