THE cumulative effects of bushfires and logging are killing Australia's alpine and mountain ash forests, experts say.
New research from the University of Melbourne has found bushfires in young ash forests do more extensive damage than those that have been standing longer, which has significant implications for how they are managed.
Alpine and mountain ash forests grow in parts of Victoria, Tasmania, NSW and the Snowy Mountains, bordering the ACT.
Researcher Chris Taylor presented his preliminary findings at the third annual Australian Forests and Climate Forum at the Australian National University on Saturday and said he would soon be publishing the paper in full.
He said bushfires in young ash forests burnt with greater severity than those in older forests, which meant they were destroyed more completely. Dr Taylor said climate change was causing bushfires in forests more often and, combined with the impact of logging, fewer were able to regenerate.
''If you reduce the age of the forest, thus alter the fire severity, and fires burn at a more frequent rate than 20 years, they're actually burning the forest before it can produce seed again,'' he said.
Dr Taylor said while the forests may be able to survive more frequent bushfires or the present logging regime, the two factors combined were causing cumulative destruction.
Ash forests should be managed so the amount of land where logging was allowed was changed depending on whether there had been fires in the area, he said. If no changes were made to how ash forests were managed, they were likely to slowly die out and acacia, or wattle trees, would take over.
Other Australian researchers had modelled the severity of bushfires in older ash forests compared with more newly established ones but this study had used empirical observations, he said.
The forum's organiser, Mike Thompson, said he brought together forestry experts to push for evidence-based forestry policy.
''There's now numbers on the table showing, for example, the amount of pollution that's coming from logging and burning our valuable state and native forests,'' he said.