Strong Legacy Effects of Prior Burn Severity on Forest Resilience to a High-Severity Fire

Lucas B. Harris, Stacy A. Drury, Alan H. Taylor

Research output: Contribution to journalArticlepeer-review

1 Scopus citations

Abstract

Legacy effects from one disturbance may influence successional pathways by amplifying or buffering forest regeneration after the next disturbance. We assessed vegetation and tree regeneration in non-serotinous Sierra lodgepole pine (Pinus contorta var. murrayana) stands after a 1984 wildfire which burned with variable severity and again after a high-severity subsequent fire in 2012. The legacy effects of the 1984 fire were amplified; seedlings and saplings were abundant in areas initially burned at low severity (1267 stems ha−1) despite high reburn severity, but regeneration was low in areas twice burned at high severity (31 stems ha−1). Our results suggest that the severity of the 1984 fire may have influenced post-2012 tree regeneration by creating variable fuel loading, which may have affected soils, litter cover and shade after the 2012 fire and therefore affected seedling establishment and survival. A canopy seed bank of unburnt cones from trees killed by the 2012 fire potentially contributed to a strong effect of prior burn severity on regeneration after the 2012 fire despite a lack of serotinous or resprouting tree species, although the influence of this canopy seedbank was likely limited to the year following the fire. Our results suggest that a low- to moderate-severity fire increases forest resilience relative to a high-severity fire even when the next fire burns at high severity.

Original languageEnglish (US)
Pages (from-to)774-787
Number of pages14
JournalEcosystems
Volume24
Issue number4
DOIs
StatePublished - Jun 2021

All Science Journal Classification (ASJC) codes

  • Ecology, Evolution, Behavior and Systematics
  • Environmental Chemistry
  • Ecology

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