Effects of cutting on soil respiration in a mixed broadleaf-Korean pine forest in western foothill of Changbai Mountain, northeast China

The objective of this study was to explore the difference in soil respiration rate under different intensities of cutting as well as the effects of soil temperature and moisture content on soil respiration rate. We measured soil respiration using infrared gas exchange analyzer of Li-Cor 8100 in the daytime during the growing seasons (May-October) of 2013-2015 in a mixed broadleaf-Korean pine (Pinus koraiensis) forest with heavy (50%), medium (25%) and light (15%) intensity cutting and uncut control (0%) plots in Jiaohe, Jilin Province in northeast China. We found that with cutting intensity increasing, soil temperature increased, and soil moisture reduced. Cutting significantly affected soil respiration and soil temperature, while there were no significant differences in soil moisture under different cutting intensities. During the growing seasons, a positive correlation was found between soil respiration and soil temperature at all sites. The best fitting model with temperature explained 73% of the variation in soil respiration in the heavy cutting treatment, 65% in the light cutting treatment,58% in the control sites, and 43% in medium cutting treatment during the measuring periods.In order to predict both soil moisture and soil temperature dependency, four two-variable linear/non-linear models were developed and evaluated.By use of those models it is possible to predict the soil respiration as a function of both temperature and moisture, with R values ranging from 45%-74%. The Q10 values were increased in the treatments of medium (2.46), heavy (2.44) and light (2.39) intensity cutting relative to the control (2.39). Our findings suggest that in order to reduce the forest soil surface CO2 emission after cutting, a reasonable cutting intensity about 15% should be adopted.