Fire is one of major natural disturbances in terrestrial ecosystem and has profound impacts on structure and functions of forest ecosystems. With increases in temperature and extreme weather events, fire occurrence and burned area in boreal forests have increased markedly over past decades. Understanding how fire regimes will change in the future climate conditions have important implications for adaptation to climate change in forest management. The existing fire predictions are mostly based on climate-fire linkages accounted for climate-related changes such as temperature, precipitation, fuel moisture, and fire weather index, vegetation are assumed to remain relatively static in these studies. Recent studies have shown that changes in species composition have an indirect effects on fire regimes through altering fuel types and fuel distribution. Without accounting for the vegetation feedbacks, the fire regimes predicted based on climate-fire linkages may overestimate the frequency and size of fire disturbances, because fuel type and structure moderate climate-fire linkages. In this study, we incorporate vegetation feedbacks into fire prediction to determine whether future fire regimes of boreal forests in northeastern China can be mitigated by the changes in forest composition. To do this, we apply a model coupling framework to integrate the dynamics of forest succession, climate-fire linkages and vegetation feedback to fire regimes for projecting fire occurrence and burned area under the future climate conditions.
Results/Conclusions
Our results suggested that climate change will increase fire occurrence density and burned area of boreal forests in the first 100 years. Whereas, the changes of forest composition will cause a reduction in fire occurrence density and burned area as deciduous species replace coniferous species in the next 150 years. Under climate change scenarios, the changes in fire regimes will accelerate the shifts of species composition in boreal forests. Vegetation feedbacks can override the direct effects of climate change on fire regimes when the shifts of forest composition significantly modify landscape flammability in the period 2100-2250. Our study demonstrates that vegetation feedbacks could reduce the effects of climate change on fire regimes in boreal forests of northeastern China. Thus, the effects of vegetation feedbacks on fire regimes should be taken into consideration for promoting boreal forests adapt to climate change and reducing the frequency fire disturbance. Plant appropriately deciduous species such as aspen may be a good option for reducing fire occurrence probability and promoting boreal forest ecosystem adapt to climate change.