Temporal patterns of soil CO2 efflux in a temperate Korean Larch (Larix olgensis Herry.) plantation, Northeast China

There is little information available regarding seasonal and annual variations in soil CO2 efflux from Korean Larch plantations, which are an important component of forests' carbon balance in temperate China. In this study, the soil respiration rate (R (s)), soil temperature (T (10)) and soil moisture (SM10) at 10 cm depth were observed in a Korean Larch (Larix olgensis Herry.) plantation in Northeast China from 2008 to 2012. Mean R (s) in growing season (GS) varied greatly, ranged from 2.32 +/- A 0.08 to 3.88 +/- A 0.09 mu mol CO2 m(-2) s(-1) (mean +/- A SE) over the period of 2008-2012. In comparison with T-model, the increase of explained variability by applying both T (10) and SM10 to the T-M model is very small. It is indicated that R (s) was controlled largely by T (10) in the present study. By accounting for 22.2 and 17.7 % of the total soil CO2 emissions in 2010/2011 and 2011/2012, respectively, the soil CO2 efflux in dormant season (DS) was an essential component of the total soil CO2 efflux. The Q (10) value in the study period was always smaller for GS than DS, suggesting that soil carbon cycling may be more sensitive to the temperature changes at low than at high temperature range. These results indicated that climate changes may have great potential impacts on temperate Larch plantations in Northeast China, owing to soil carbon emissions of Larch plantation during the long period of DS being more sensitive to T (10) than in GS, and played a significant role in the annual forest ecosystems carbon budget.