University Of Tasmania
Bowman et al 2016.pdf (476.63 kB)

The relative importance of intrinsic and extrinsic factors in the decline of obligate seeder forests

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journal contribution
posted on 2023-05-18, 20:52 authored by David BowmanDavid Bowman, Grant WilliamsonGrant Williamson, Lynda PriorLynda Prior, Murphy, BP
Forests that regenerate exclusively from seed following high-severity fire are particularly vulnerable to local extinction if fire frequency leaves insufficient time for regenerating plants to reach sexual maturity. We evaluate the relative importance of extrinsic (such as fire weather and climate cycles) and intrinsic (such as proneness to fire due to stand age and structural development) factors in driving the decline of obligate seeder forests. We illustrate this using obligate seeding alpine ash (Eucalyptus delegatensis) forests in the montane regions of Victoria, Australia, that were burnt by megafires in 2003 (142,256 ha) or 2007 (79,902 ha), including some twice-burnt areas (11,599 ha). Geospatial analyses showed only a small effect of stand age on the remote sensing estimates of crown defoliation, but a substantial effect of forest fire weather, as measured by forest fire danger index (FFDI). Analysis of meteorological data over the last century showed that 5-year increases in FFDI precede cycle major fires in the E. delegatensis forests. Such strong extrinsic climate/weather driving of high-severity fires is consistent with the ‘interval squeeze model’ that postulates the vulnerability of obligate seeder forests to landscape-scale demographic collapse in response to worsening fire weather under climate change.


Publication title

Global Ecology and Biogeography










School of Natural Sciences


Wiley-Blackwell Publishing Ltd.

Place of publication

United Kingdom

Rights statement

Copyright 2016 The Authors Licensed under Creative CommonsAttribution-NonCommercial-NoDerivs 3.0 Unported (CC BY-NC-ND 3.0)

Repository Status

  • Open

Socio-economic Objectives

Ecosystem adaptation to climate change