Does forest thinning reduce fire severity in Australian eucalypt forests?

Forest thinning has been proposed to reduce fire severity. However, evidence to support this strategy in Australia is scant. We completed a detailed empirical analysis of stand history data from forests burned in wildfires in 2009 in south-eastern Australia, to address the question:Does forest thinning reduce fire severity? The answer varied depending on fire type (Crown Burn vs. Crown Burn/Crown Scorch), forest type, and stand age. For the statistical relationship for Crown Burn, there were no thinning effects in ash-type forests. For mixed species forests, thinning reduced the probability of Crown Burn in young stands but increased it in older stands. Data for the fire severity category of Crown Burn/Crown Scorch revealed that thinning generally elevated fire severity, irrespective of stand age, forest type, or fire zone. Except for 20- to 40-year-old mixed species forest subject to Crown Burn, proposals for thinning to reduce fire severity have limited support.

Automated summary

The effectiveness of forest thinning in reducing fire severity varies depending on fire type, forest type, and stand age. While thinning may reduce the probability of Crown Burn in young stands of mixed species forests, it generally elevates fire severity in other cases. Thinning proposals to reduce fire severity have limited support, except for specific scenarios like 20- to 40-year-old mixed species forests subject to Crown Burn.