Resilience of forests to past fire disturbance in the Changbai Mountains, Northeastern China

Recent increases in wildfire in many parts of the world have raised awareness of the need to understand what controls post-fire forest resilience. Palaeo-records of fire and vegetation can provide a much needed perspective on ecosystem resilience to fires. Here, we used simulations of forest biomass and tree numbers in response to climate changes and compare these simulations with a 13,000 year long record of fire and vegetation changes from Gushantun (GST) peatland in the Changbai Mountains, to examine the stability and resilience of forest trees after fires. Changes in the characteristics of the fire regime through time were used to explore the consequences of different fire regimes on ecosystems and address the question of which aspects of the fire regime have the highest impact on the degree of disturbance and the loss of forest resilience. Our analyses indicate that the severity and frequency of fires were much higher in the early Holocene than in other periods, and that the study area experienced different types of fire disturbances throughout the period. Fire severity and frequency have a similar impact on forest biomass in the Changbai Mountains, with the largest changes resulting during intervals of frequent severe fires. High severity fires were more destructive to forest openness and were closely related to forest recruitment, while the effect of frequency on openness is not reflected in this study. All species exhibited low stability following high severity fires. Frequent severe fires can cause a shift in forest community composition and loss of resilience.