Soil Respiration Of Larix Gmelinii Rupr. Forest In The Da Xing’an Mountain And The Responses To The Fire Disturbances

Soil respiration is one way of CO2emissions from ecosystems to the atmospheric. The soil respiration of boreal forest which is widely distributed occupies a pivotal position in the global carbon cycle. Wildfire is a very important disturbance in northern Chinese forest, which also is an important factor affecting the carbon cycle, but most of researches of carbon cycle little regard for the impact of forest fire disturbance. Soil respiration of Larix gmelinii forest of northern and southern Da Xing’an Mountain was compared in this study, and the effects of different intensity fire disturbance (severe, moderate, mild) were analyzed. The specific content of the study was:(1) Comparing Rs and Rh of Da Xing’an Mountain southern and northern Larix gmelinii;(2) estimating the impact of different fire disturbance intensity on Rs and Rh of the Da Xing’an Mountain Larix gmelinii;(3) analyzing the relationship between Rs/Rh and soil temperature/soil moisture content, and building the models.The results were as follows:1) Southern sample:Rs ranged from2.59to9.33μmol·m-2·s-1, Rh ranged from1.79to6.78μmol·m-2·s-1;northern sample:Rs ranged from1.47to6.63μmol·m-2·s-1, Rh ranged from1.34to5.32μmol·m-2·s-1;severe sample:Rs ranged from1.32to7.50μmol·m-2·s-1, Rh ranged from0.65to5.69μmol·m-2·s-1; moderate sample:Rs changes in the range of1.43～7.27μmol·m-2·s-1, Rh ranged from1.28to5.89μmol·m-2·s-1;mild sample:Rs ranged from1.77to6.02μmol·m-2·s-1,Rh ranged from1.79to6.78μmol·m-2·s-1.2) The ranges of variation of soil temperature and Q10were as follows:southern sample: soil temperature of total soil respiration for1～17℃, Q10for3.16, soil temperature of heterotrophic respiration for3～15℃, Q10for3.59; northern sample:soil temperature of total soil respiration ranged from4to10°C, Q10for3.74, soil temperature of heterotrophic respiration ranged from3to11℃, Q10for2.78; severe sample:soil temperature of total soil respiration for3～23℃, Q10for3.25,soil temperature of heterotrophic respiration for3-22℃, Q10for1.49; moderate sample:soil temperature of soil total respiration for1～19℃, Q10for3.85, soil temperature of heterotrophic respiration for2～19℃, Q10for2.81; mild sample: soil temperature of total soil respiration for2～18℃, Q10for3.03, soil temperature of heterotrophic respiration for2～18℃,Q10for2.65.3) In this study, the prediction model of soil respiration taking into account soil temperature and humidity and their interaction effect, explained70.90%and87.78%of Rs and Rh changes of the south sample, explained32.41%and42.38%of Rs and Rh changes of the northern sample, explained76.87%and60.56%of Rs and Rh changes of the severe sample, explained70.52%and69.06%of Rs and Rh changes of the moderate sample, explained 53.59%and49.45%of Rs and Rh changes of the mild sample.