Emulating natural fire effects using harvesting in an eastern boreal forest landscape of northeast China

Questions: Efforts to emulate natural fire effects through harvesting have met with limited success due to insufficient consideration of variable fire severities and spatial heterogeneity of fire regimes (e.g. mean return interval and fire size) in boreal ecosystems. What is the relative importance of fire severity and spatial heterogeneity on tree species composition, age structure and spatial pattern? Location: An eastern boreal forest landscape of northeast China, consisting of larch and birch forests. Methods: We constructed a factorial design of forest management alternatives and conducted simulation experiments using a landscape disturbance and succession model, LANDIS. We used a management area delineation method to simulate spatial heterogeneity of fire regime and a silvicultural regeneration method to simulate variable fire severity. Results: Management area delineation had a greater influence on tree species composition, age structure and spatial pattern of the boreal forests than the silvicultural regeneration method. The silvicultural regeneration method had more influence on the age structure of larch than birch, due to the variable severity of fire on larch. Conclusions: Spatial heterogeneity of fire regime has a more important influence on ecosystem characteristics than fire severity in this eastern boreal landscape. Efforts to emulate natural fire effects through harvesting should first account for the effects of spatial heterogeneity of the fire regime. It is necessary to delineate the landscape into fire management units and incorporate variable fire severities in harvest prescriptions for each unit. Spatial heterogeneity of fire regime plays more important influence on ecosystem characteristics than fire severity in an eastern boreal landscape of Northeast China. To emulate natural fire effects, delineating landscape into fire management units and incorporate variable fire severities in harvest prescriptions for each unit are necessary.