Understanding the effects of forest management practice on soil respiration (R_s) and its temperature sensitivity (Q₁₀) is crucial for the accurate estimation of the global carbon budget. However, the dynamics of Rs and Q₁₀ resulting from plantation thinning are not well understood.

Professor BAO Wei-Kai and team of restoration ecology from Chengdu Institute of Biology conduct a study to evaluate the impacts of forest thinning on R_s and Q₁₀ in a pine plantation at Maoxian mountain Ecosystem Research Station, Chinese Academy of Sciences in Sichuan, China, located in the eastern Tibetan Plateau (31° 37' N and 103° 54' E). They applied the technique of thinning by simulating gap formation and measured R_s monthly before (from July to November 2008) and after (from December 2008 to June 2012) thinning, combining with monthly microclimatic factors.

The study found that forest thinning by gap formation could slightly increase soil temperature and moisture immediately following thinning. Soil temperature was the dominant factor controlling R_s and Q₁₀. But during the relative dry period soil moisture played an important role in controlling R_s. Although there was a slight increase in R_s and Q₁₀ shortly after thinning, the difference in R_s between the control and thinned stands disappeared one year after thinning. Therefore, they conclude that forest thinning has a relatively small impact on soil CO₂ emissions and Q₁₀ as compared to the greater role of inter-annual climatic variability.

The study entitled “Responses of soil respiration and its temperature sensitivity to thinning in a pine plantation” has been published in Agricultural and Forest Meteorology. (http://www.sciencedirect.com/science/article/pii/S0168192312003619).