Forest and fire risk dynamics in the Great Xing'an Mountains, Northeastern China: A spatial simulation study

Natural disturbance-based forest management, based primarily on the understanding of natural disturbance regimes and forest dynamics, provide sustainable forest management paradigms to maintain biodiversity and essential ecological function in managed forested regions. So understanding how forest ecosystem and fire dynamics respond to historic and current fire regime pose great significance in designing scientifically sound management plans for Great Xing'an Mountains in the Northeast China. We used a spatially explicit landscape dynamics model, LANDIS, to simulate the long-term forest response and fire dynamics under historic fire regime (before 1950s) and the fire suppression (after 1950s). Specifically, we compare how the fuel loads and fire hazards, and forest tree species abundance response under the two scenarios. Under the fire suppression scenario, fire risk will quickly increased to a dangerous level, about 80% of the landscape will carrying a high level of fire risk at the end of the simulation; both fine fuel and coarse fuel will rise to medium-high level after a few decades' suppression. Generally, fires tend to be more catastrophic and less frequent. Fire suppression results in less frequent, but more intense fires. Fire suppression can also decrease the proportion of coniferous forests, increase the proportion of deciduous forests and alter forest age structures. The results suggest that extensive additional forest management activities, such as prescribe burned, fuel load reduction, uneven-aged harvesting should be implemented to maintain low level of fire risk and forest type diversity. Further studies are needed to evaluate the effects of prescribed burning and fuel load reduction under the fire suppression, and to find the fine balance among fire suppression, maximal timber production, and sound ecological function.