关键词: 阔叶红松林, 皆伐迹地, 土壤呼吸作用, 温度, 土壤水分

Abstract:

Aims Soil respiration is the second largest flux in the global carbon cycle. Human activity, especially forest cutting, had brought a lot release of soil carbon. But the effect of forest clear-cutting on soil respiration was not inadequately understood. We chose Korean pine forest in Changbai Mountain as the case study area. Our aim is to compare soil respiration in clear-cut fields with that in natural Korean pine forests, and to reveal the effects of clear-cut on the density and pattern of soil respiration.
Methods During the growing seasons from 2003 to 2005, soil respiration was measured by a closed static chamber system in the clear-cut fields and Korean pine forests in Changbai Mountain. Soil temperature and moisture during the upper layers were observed by geothermometer and TDR system.
Important findings The results showed that diurnal variation of soil respiration at clear-cut plot could be expressed as single peak curve, and the times of the maximum and the minimum soil respiration values appeared 2-4 hours earlier than those in forest plot, which consisted with that of soil temperature at 5 cm depth. Soil respiration rate at forest plot was higher with the proportion of 75% than that in clear-cut plot during the growing season. Soil temperature had a significant exponential relationship with soil respiration. Soil water may have negative effect on soil respiration during the growing season with high frequency precipitations. The soil respiration model including the effects of soil water and temperature could explain soil respiration variation much better than temperature-based soil respiration model. The management of clear-cut forest had obvious effect on the dynamic characteristics and intensity of soil respiration due to the decrease in biomass and the change in microclimate in Korean pine forest.

Key words: broad-leaved Korean pine forest, clear-cut, soil respiration, temperature, soil water content