Blackened trees in a landscape

Vegetation in the Brindabellas devastated by the 2003 bushfires.

How vegetation responds to high intensity bushfires

A ten year study of the effects of the 2003 Canberra bushfires on vegetation in the Brindabella ranges has found that the Australian bush is more resilient than was thought.

  • 18 January 2013 | Updated 20 June 2013

Bushfire has been part of the Australian landscape for millions of years. We have all seen the devastating effects it can have, but a ten year study of the Brindabella ranges has shown that Australia’s forests can bounce back even after high intensity fire.

Background

In the summer of 1996, CSIRO’s Michael Doherty set up a vegetation survey and mapping project across the Burrinjuck and Bimberi Nature Reserves, and the Brindabella National Park, west of Canberra.

Over 160 vegetation plots were established, with plant species, vegetation cover, structure and height being recorded and photographs being taken of each plot.

In 2003 some of the worst fires in Canberra’s history swept through the area, with all but three of the existing plots burnt to a greater or lesser degree. This created the perfect opportunity to explore the effects of fire on vegetation, in a ‘before’ and ‘after’ study.

“Prior to this study, there was little known about how fire affected the hundreds of plant species that are found in the Brindabellas,” said Michael.

“This research is informing fire management for biodiversity conservation in reserves in South East Australia.”

The amount of vegetation burnt varied from plot to plot, but even where fires burnt at high intensity, the plants are recovering well"

Michael Doherty

Research

After sorting the plots into low and high fire severity, each plot was assessed for changes in plant species composition (which species were present), plant species richness (how many different species were present), and vegetation structure (the way that vegetation is arranged into layers). These changes were assessed seven times over the last ten years.

“Using the permanent sites we set up 17 years ago, we’ve been able to measure changes in species over time and compare the response to different sorts of fire in different types of vegetation,” said Michael.

Results

Encouragingly, researchers have found that 80 per cent of plant species have re-sprouted, even after 100 per cent leaf scorch.

Of the 20 per cent of plant species that were killed by 100 per cent leaf scorch, all species were able to recover thanks to seeds protected in the soil or in capsules held on the plants.

This meant that even though the plants themselves were killed, the species re-established in the landscape, so no plant species were lost from the study area.

“The amount of vegetation burnt varied from plot to plot, but even where fires burnt at high intensity, the plants are recovering well,” said Michael.

“It has been amazing to see that even though fires, particularly large, high intensity fires, aren’t common in this area, species have been able to re-establish themselves.”

The information gained from this project will assist in determining fire management principles for the different vegetation types found in the study area, particularly in relation to how long communities may need to be free of fire before they have fully recovered to their pre-fire condition.

Photos

These photographs show the impact of the fires and the subsequent recovery of the vegetation:

Three photos of the same landscape comparing pre bushfire and two post bushfire recovery.

The original image of the vegetation taken in 1997. The Brindabella landscape after the bushfires, taken in November 2003. The same mountainous view of the Brindabellas taken in 2012.

The original image of the vegetation taken in 1997. The Brindabella landscape after the bushfires, taken in November 2003. The same mountainous view of the Brindabellas taken in 2012. Larger view of comparison photos.

Partners

This research has been undertaken in partnership with the NSW Office of Environment and Heritage and the Australian National University.

Find out more about CSIRO's bushfire research.