Postfire recovery trajectories of bulldozed versus burned chaparral eight years postfire

Background

We examined vegetation diversity, structure, and composition on and off fuel breaks established during a 2013 wildfire in California chaparral shrublands. Vegetation was sampled 8 years following the fire to identify any persistent changes in structure or composition caused by this fire management activity, with implications for postfire vegetation recovery.

Results

While species diversity and cover of lifeforms did not differ on and off fuel breaks, species composition and regeneration strategy of dominant shrubs differed significantly. Sites in fuel breaks were dominated by fast-growing subshrubs that regenerate from seeds and are more readily dispersed into sites—species that are typical indicators of the coastal sage scrub community. Sites off fuel breaks were characterized by a mix of resprouting and seeding shrubs typically associated with the chaparral community.

Conclusions

Fuel breaks established by bulldozers during wildland firefighting have impacts on chaparral composition because the actions of the dozer remove soil seed banks and damage resprout “banks” (lignotubers). The permanence of these changes is likely to be related to the frequency and severity of fire suppression actions.