How do slow-growing, fire-sensitive conifers survive in flammable eucalypt woodlands?

J. S. Cohn*, I. D. Lunt, K. A. Ross, R. A. Bradstock

*Corresponding author for this work

Research output: Contribution to journalArticle

31 Citations (Scopus)

Abstract

Question: To what extent do low flammability fuel traits enhance the survival and persistence of fire-sensitive (slowing-growing, non-serotinous, non-resprouting) dominant trees in highly flammable landscapes, under varying fire-weather conditions? Location: Mixed forests co-dominated by flammable Eucalyptus species and fire-sensitive Callitris glaucophylla in Pilliga State Forest, southeast Australia. Methods: The influence of vegetation composition (relative abundance of Callitris and flammable Eucalyptus) on fire intensity and survival of fire-sensitive Callitris was assessed across gradients of Callitris abundance in mixed Eucalyptus-Callitris forests that burned under low-moderate and extreme fire-weather conditions. Results: In areas that burned under low-moderate fire-weather conditions, as Callitris abundance increased, fire intensity declined and Callitris survival increased (46%). By comparison, in extreme fire-weather conditions, lower fire intensity at higher levels of Callitris abundance, was not sufficient to increase Callitris survival (4%). Callitris survival was also positively related to trunk diameter. Ground fuel type, but not biomass, varied with vegetation composition. Conclusions: These results demonstrate that flammable feedbacks, mediated by low flammability fuel traits of dominant trees, can provide an important mechanism for enhancing the survival and persistence of slow-growing, non-serotinous, non-resprouting, fire-killed trees in highly flammable landscapes. By modifying vegetation and fuel structure, patches of fire-sensitive Callitris reduce fire intensity, and thereby reduce Callitris mortality, enhancing population persistence. However, this feedback loop is insufficient to ensure Callitris survival under extreme fire-weather conditions, when fire intensity is greater. After burning, stands remain vulnerable to future fires, until trees grow large enough to modify fuel levels and reduce stand flammability.

Original languageEnglish
Pages (from-to)425-435
Number of pages11
JournalJournal of Vegetation Science
Volume22
Issue number3
DOIs
Publication statusPublished - Jun 2011

Keywords

  • Australia
  • Callitris
  • Coexistence
  • Disturbance intensity
  • Fire-weather
  • Fuels
  • Non-resprouter
  • Resprouter
  • Spatial heterogeneity
  • Vegetation composition

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