Understanding the effects of forest management practice on soil respiration (Rs) 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 his team of restoration ecologists from Chengdu Institute of Biology conducted a study to evaluate the impact of forest thinning on Rs 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 Rs 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 Rs and Q10. But during the relative dry period soil moisture played an important role in controlling Rs. Although there was a slight increase in Rs and Q10 shortly after thinning, the difference in Rs between the control and thinned stands disappeared one year after thinning. Therefore, they concluded 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.
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