Abrupt fire regime change may cause landscape-wide loss of mature obligate seeder forests

• Published in: Global change biology Vol. 20; no. 3; pp. 1008 - 1015
• Main Authors: Bowman, David M. J. S., Murphy, Brett P., Neyland, Dominic L. J., Williamson, Grant J., Prior, Lynda D.
• Format: Journal Article
• Language: English
• Published: Oxford Blackwell Publishing Ltd 01.03.2014; Wiley-Blackwell
• Subjects: adults; Alps region; Animal and plant ecology; Animal, plant and microbial ecology; Ash; Austria; Biological and medical sciences; Biomass; Carbon; climate change; Climatology. Bioclimatology. Climate change; deforestation; Earth, ocean, space; Eucalyptus; Eucalyptus - growth & development; Eucalyptus delegatensis; Exact sciences and technology; External geophysics; Extreme weather; fire management; fire regime; fire severity; fire weather; Fires; Flammability; forest; Forest & brush fires; Forest and land fires; forest trees; Forestry; forests; fuels (fire ecology); Fundamental and applied biological sciences. Psychology; General aspects; General forest ecology; Generalities. Production, biomass. Quality of wood and forest products. General forest ecology; growth & development; Landscape ecology; Meteorology; mortality; Phytopathology. Animal pests. Plant and forest protection; shrubs; sowing; Terrestrial ecosystems; Trees; Trees - growth & development; Weather damages. Fires; wildfire; Austria; Australia; Alps region; Deforestation; Forests; forest; Landscape; Loss; Woody plant; Dynamical climatology; Climate change; Eucalyptus; Fire ecology; fire management; Dicotyledones; Fires; wildfire; Angiospermae; Myrtaceae; Spermatophyta; Vegetation fire; climate change; deforestation
• ISSN: 1354-1013; 1365-2486; 1365-2486
• DOI: 10.1111/gcb.12433

Obligate seeder trees requiring high‐severity fires to regenerate may be vulnerable to population collapse if fire frequency increases abruptly. We tested this proposition using a long‐lived obligate seeding forest tree, alpine ash (Eucalyptus delegatensis), in the Australian Alps. Since 2002, 85% of the Alps bioregion has been burnt by several very large fires, tracking the regional trend of more frequent extreme fire weather. High‐severity fires removed 25% of aboveground tree biomass, and switched fuel arrays from low loads of herbaceous and litter fuels to high loads of flammable shrubs and juvenile trees, priming regenerating stands for subsequent fires. Single high‐severity fires caused adult mortality and triggered mass regeneration, but a second fire in quick succession killed 97% of the regenerating alpine ash. Our results indicate that without interventions to reduce fire severity, interactions between flammability of regenerating stands and increased extreme fire weather will eliminate much of the remaining mature alpine ash forest.