Abstract: Fire is a major disturbance in boreal forest ecosystems, affecting not only forest productivity and species diversity but also biogeochemical processes. In this study, we investigated the effects of fire (one year after fire) on soil physicochemical properties, microbial biomass and nutrients (N, P, and K) availability in a boreal Dahurian larch forest that was burned in year 2010 at the Huzhong Natural Reserve in the Great Xing’an Mountains of Northeast China. Our results showed that fire significantly decreased soil moisture, organic matter depth, dissolved organic carbon content, total C∶N ratio and microbial biomass in burned plots, but increased soil pH significantly, as compared with the control plots. However, no significant differences were observed in these soil properties between different fire intensities. After light and heavy fires, the soil N availability was significantly higher than the control, but less difference was found between the two fire intensities. Soil P availability was also significantly higher after fire, and there existed significant difference between the two fire intensities. Fire showed no significant effects on soil K availability.

Key words: the Yellow River Delta, coastal wetland, soil respiration, change in precipitation amount, photosynthesis.