Objective The spatiotemporal changes of soil moisture content under different fire intensities were analyzed by sequentially monitoring at the fixed points in the mild-, moderate-, severe-burned area of the Larix gmelinii forest, and the forming mechanism was discussed in order to understand the effects of soil moisture variation on vegetation restoration and provide references for artificial regulation in the early years after forest fire.
Method The fixed monitoring points were conducted by latticed co-coupled sampling method, then set fire. The burned sample plots were divided into the mild-, moderate-, severe-burned according to the fire intensity class, and soil moisture content was determined by the oven drying method before the burning, afer the burning, following the snowmelt season, and in the growing season, respectively.
Result After the fire, (1) soil moisture content decreased immediately in the mild-, moderate-, severe-burned area following the burning, further decreased sharply in the next spring, and rose in the growing season. (2) Soil moisture content in the severe-burned area was significantly lower than those in the mild-, moderate-burned area before the growing season, and no difference was found among the three areas in the growing season. (3) There was significantly negative correlation between the spatial pattern of soil moisture content or its relative change and fire intensity before the growing season.
Conclusion In the early years of post-fire coniferous forest restoration in the cold temperate zone, soil moisture content maybe limit vegetation restoration and regeneration in the severe-burned area in spring, and the regulation of rainwater harvesting and water conservation should be strengthened.