Environmental relationships with the interannual and seasonal variation of soil respiration in a cedar (Platycladus orientalis) plantation in northern China

The relationships between soil respiration and environmental factors determine the effect of warming soil on the carbon balance in temperate forest ecosystems and on changes in atmospheric CO2 concentrations. Here, we used 3 years of data regarding soil respiration rates (R-s), soil temperature (T-s), and soil volumetric water content (theta) from a 50-year-old mature cedar (Platycladus orientalis L.) plantation at Jiufeng Mountain, Beijing, China, to demonstrate the seasonal and interannual variation of R-s dependence on T-s and theta throughout the period 2008-2010. We used the exponential model to calculate the temperature sensitivity indicator Q(10) and we examined the annual and seasonal patterns of R-s and Q(10). The R-s correlated with T-s annually (p < 0.05). The R-s-T-s exponential relationship was significant in the autumn and winter (p < 0.05), while the combined T-s and theta relationships with R-s were significant in the spring and summer (p < 0.001). The spring R-s anomalies caused by drought appeared to have carryover effects that translated to R-s anomalies in the following summer. Finally, the summer R-s, which was influenced by the coincident precipitation and theta anomalies, determined the magnitude of the annual total amount of soil respiration. This result has implications for how abiotic factors may drive shifts in seasonal patterns of soil respiration under a changing climate.