Effect of Fire Disturbances on Short-term Soil Respiration and Its Components of Larix gmelinii and Betula platyphylla Forests in Xiaoxing’an Mountains
Abstract:In burned areas of Larix gmelinii and Betula platyphylla forests in Xiaoxing’an Mountains, with the unburned nearby areas as the control, we examined the rate of soil respiration in burned and control areas, and studied the differences of short-term soil respiration between the burned and control areas. By comparing the rate of soil respiration between the burned and control areas of two forest types in same months, there was significant difference in august(P<0.05), while it was not obvious in other months(P>0.05). The overall mean rate of soil respiration in B.platyphylla forest had a descending trend after fire disturbance, while it was increased after the fire in L.gmelinii forest. The specific performances were as follow: the mean rate of Rs over the growing season in the burned areas(3.91 μmol·m-2·s-1) was lower than the control areas(5.29 μmol·m-2·s-1) in B.platyphylla forest, and Rh, Ra, the overall mean rate of soil respiration over four months were also declined after the fire. The rate of Rs in burned plots(4.62 μmol·m-2·s-1) was higher than that in unburned plots(4.18 μmol·m-2·s-1) over the growing season in L.gmelinii forest, Rh, Ra and the overall mean soil respiration rate in burned plots was also higher than those in control plots. The variation in the soil respiration rate could be explained by soil water content and soil temperature and their interaction at the depth of 5 cm. By regression, fitted T, W and T×W model could explain that Rs rates in control plot of B.platyphylla and L.gmelinii forests were 82.9% and 88.6%, respectively. It was 88.8% in post-fire plot of B.platyphylla forest, higher than the control. While it declined to 72.9% in burned plot of L.gmelinii forest. We found out the change of fire disturbance on soil respiration, and would provide a scientific basic data on the effects of fire disturbance on short-term soil respiration in the soil respiration on the response of fire disturbance.