Fire fuel found to diminish in ageing Great Western Woodlands

February 6, 2014 by Chris Thomas
Fire fuel found to diminish in ageing Great Western Woodlands
“The legacy of fires that have occurred in the GWW over the past few decades means that large areas will soon be passing into a stage of post-fire development with higher fuel availability," Dr Prober says. Credit: Sydney Oats

Research looking at vegetation structure changes in gimlet (Eucalyptus salubris) woodlands has provided insights into how time affects fuel availability for fire and habitat for biodiversity.

A study by Drs Carl Gosper, Colin Yates and Suzanne Prober from the Department of Parks and Wildlife and CSIRO Ecosystem Sciences measured the effects of "time-since-fire" on the 16 million ha Great Western Woodlands (GWW).

The GWW is the largest remaining area of intact Mediterranean-climate woodland on Earth, stretching from the edge of the Wheatbelt to Kalgoorlie-Boulder through to north-east deserts and the Nullarbor Plain.

The area was a focus for the research because of its international significance and supported by the GWW Conservation Strategy and Terrestrial Ecosystem Research Network.

With fire shaping vegetation composition and diversity, researchers sought to understand how vegetation communities change with and without fire over time.

They used a "space for time" approach by selecting gimlet woodlands burnt at different times, ranging from about five to 400-plus years ago and then comparing their characteristics.

"This assumes the woodlands would be much the same, other than differences due to time-since-fire, so we were careful to select sites similar in most other parameters, such as climate," Dr Prober says.

"To estimate how long ago the woodland was burnt, we used a combination of satellite imagery, tree rings and tree diameter.

"Once we selected this set of about 70 sites, we then measured many different things, such as plant composition and diversity, litter cover and dead trees."

The most important result, according to Dr Prober, was finding that fuel availability peaked at intermediate times since fire—about 35 to 150-plus years ago—and was lower in old growth woodland.

For a burnt woodland to return to an old-growth state, this means it needs to pass through a long period where it is more prone to fire without being burnt.

"Another result of interest was that we did not observe significant tree mortality in old growth stands," Dr Prober says.

"There's no indication old growth stands are becoming moribund and need to be burnt.

"The legacy of fires that have occurred in the GWW over the past few decades means that large areas will soon be passing into a stage of post-fire development with higher fuel availability.

"From a management point-of-view, the dramatic changes in with time-since-fire have important implications for biodiversity."

As a result, Dr Gosper says it would be desirable to have a significant proportion of gimlet woodland within the GWW in a long unburnt state for biodiversity conservation.

Explore further: Presence of snails points to forest recovery

Related Stories

Presence of snails points to forest recovery

February 16, 2010

A team of Catalan researchers has studied the changes in the make-up of animal populations following forest fires, and have concluded that malacological fauna are a good indicator of forest recovery. The conclusions of this ...

Future fire -- still a wide open climate question

July 7, 2011

How the frequency and intensity of wildfires and intentional biomass burning will change in a future climate requires closer scientific attention, according to CSIRO's Dr Melita Keywood.

79 years of monitoring demonstrates dramatic forest change

January 6, 2014

Long-term changes to forests affect biodiversity and how future fires burn. A team of scientists led by Research Ecologist Dr. Eric Knapp, from the U.S. Forest Service's Pacific Southwest Research Station, found dramatic ...

Savanna vegetation predictions best done by continent

January 30, 2014

A "one-size-fits-all" model to predict the effects of climate change on savanna vegetation isn't as effective as examining individual savannas by continent, according to research published in Science this week.

Recommended for you

Methane production reduced in ruminants

May 3, 2016

Researchers at the Spanish National Research Council (CSIC) have taken part in a study of the effect of one molecule, 3-nitrooxypropanol, in inhibiting methane production in ruminants. The work has been published in the Proceedings ...

Hurricanes key to carbon uptake by forests

May 2, 2016

While hurricanes are a constant source of worry for residents of the southeastern United States, new research suggests that they have a major upside—counteracting global warming.

Learning from El Niño as La Niña Odds Rise

May 2, 2016

Although El Niño is weakening, its ramifications continue to be felt around the world. Drought and resulting food insecurity is one of the major implications for southeast Asia, eastern and southern Africa, Central America ...

How much does groundwater contribute to sea level rise?

May 2, 2016

Groundwater extraction and other land water contribute about three times less to sea level rise than previous estimates, according to a new study published in the journal Nature Climate Change. The study does not change the ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.