Abstract: Carbon dioxide releases from stem surface and soil are important parts of forest ecosystem carbon cycle, but how pruning treatment impacts stem surface and soil CO₂ effluxes is unclear. In this paper, we examined the effect of photosynthate supply on stem surface and soil CO₂ effluxes in a Chinese fir plantation forest by pruning branches (CK, light pruning, and heavy pruning). Stem surface and soil CO₂ effluxes were measured with the LI-6400-09 portable photosynthesis system for a month. The results showed that pruning had no significant effect on stem surface CO₂ efflux, although the maximum sap flow velocity decreased slightly. Pruning treatment decreased soil CO₂ efflux slightly, with reductions by 11.8% and 17.9% for light and heavy pruning treatments, respectively compared to the control. However, there was no significant difference among the three treatments. Our results indicated that shortterm effects of pruning on stem surface and soil CO₂ effluxes were negligible in the Chinese fir plantation forest.

Key words: obstacle degree, vulnerability, Haiyuan County, set pair analysis, agro-household livelihood