Driving through the fire-affected areas of Yarloop and Waroona, it is surprising to see how quickly our native bush can recover from a disaster so intense and widespread.
Department of Parks and Wildlife scientist Lachie McCaw has spent years researching how our plants cope with the fire-prone lands of the south-west.
“Prior to Aboriginal times, there’s evidence from charcoal sediments that you’ve had fire going back millions of years, that would’ve been caused by lightning,” Lachie said.
“And the Aboriginal people are known to have used fire for a whole range of purposes.”
He said these controlled fires were most commonly used to keep travel routes open.
“It’s a fire-prone environment in the south-west here, because most of our rainfall is during the winter, and then we have an extended dry season from about now until about May/June,” Lachie said.
“The plants, and I suppose the animal communities that depend on that vegetation, they have experienced many many hundreds of cycles of fire, and so they have a range of adaptations that allow them to survive and reproduce in the presence of fire.”
First Lachie explained the two distinct strategies that plants use to recover quickly after a fire, producing that fresh verdant vegetation you can see driving through the area, just one year on from the blaze.
Some plants – grass trees, eucalypts, Jarrah and Marri – are not killed by the fire, though they lose their leafy crowns.
The trees have dormant buds protected within their thick, woody trunks, which the tree can re-sprout from.
“If you went to Yarloop today, already you’d see lots of fresh shoots coming out on the crowns of the eucalypt trees, the Jarrah and the Marri, and some of the she-oaks,” Lachie said.
Other ‘sprouters’, smaller shrub-like plants, will sprout from stock hidden beneath the soil: a good example of this are Zamia palms.
“They’ll have their leaves killed by fire but then they’ll resprout quite quickly,” Lachie said.
Other plants rely on seed to recover from fire.
Wattles, for instance, have a hard seed that needs stimulus from either heat or physical impact to help them germinate.
“So I would expect that in large areas that were burnt by the fire in January this year, there would be lots of wattles coming up this first season,” Lachie said.
There are other plants that store their seeds in capsules, such as Hakeas or Banksias.
“Often they’ve got a big woody fruit, and that will hold the seed quite tightly on the plant until either the plant dies of drought or old age, or by fire,” Lachie said.
“The seeds will open and drop the seeds onto the ground.”
Lachie said that because of the large amount of space freed up by the fire, small quick-growing plants like orchids will often thrive, no longer in competition with larger plants.
Unfortunately, the same applies for weeds.
Many people have told me of the beautiful pink flowers blooming in the fire-affected areas, but these plants are likely gladioli or watsonia: both introduced species.
“Weeds can be a problem, particularly in smaller pieces of remnant bush, so if you’ve got a patch of bush on the farm that’s all surrounded by pasture or crop, then you have a lot of seed that can invade the bush land,” Lachie said.
He said that although sometimes community revegetation projects can help bush recovery along, the most important thing to focus on was weed removal.
He recommends working with approved weed-removal projects run by local organisations, to ensure the plants you are pulling up are actually weeds.
“The effects of that fire, because it was so intense in places, will be visible for decades to come… but I wouldn’t say the forest will never recover,” he said.
The Australian bush is surprisingly resilient, and though fire brings devastation, like a phoenix it seems the forest can be reborn from the ashes.
Do you have a gardening question for Jess? Send your queries to jess.cockerill@fairfaxmedia.com.au
