Adelaide Hills residents urged to preserve native vegetation in preparation for bushfire season

Residents in the Adelaide Hills are being urged not to clear too much native vegetation as they prepare for a hotter and drier bushfire season.

While there has been recent heavy rain, this summer will be the first in many years to feature higher fuel loads paired with the hotter, drier El Niño weather pattern.

Landholders are allowed to clear native vegetation up to 10 metres from their homes without a permit but are encouraged not to cut down mature trees.

Some landholders believe the heightened fears for this fire season could lead to people clearing too much native vegetation.

Former park ranger and Landcare volunteer Steve Taylor maintains native vegetation on his block.

"There are ways and means of doing that without destroying or reducing too much food and habitat opportunities for native wildlife," he said.

"Finches for example require native grass seed to survive and get through the summer.

"It's not necessary to use herbicide when you can use physical removal to get rid of annual grasses which are for the most part weeds and are one of the biggest threats around a house on a rural property, because they will ignite so readily."

The Adelaide Hills Council estimates only 13 per cent of the Mt Lofty Ranges' original native vegetation remains after most of the region was cleared for farming and housing.   

Gumeracha landholder Hans Griesser has learned from the Sampson Flat bushfire, which came through his property in 2015, in thinking about where he plants certain species and how he maintains the native vegetation on his block. 

He has kept mature native trees, including near his house, but ensures that fine fuels and ladder fuels like twigs, shrubs and grasses are cleared beneath them ahead of bushfire season.

"When the fire came through here I saw the effects of how it actually burns in different places and how the density of the understorey plants really affects the intensity of the fire and that you can have gum trees without having the risk of a major fire," he said.

"With the grass cleared really low among the gum trees, there weren't any serious fire effects … just a few black licks for a few centimetres up the trunks."

Mr Griesser, the chair of the Kersbrook Landcare Group, has planted native shrubs in segregated patches where flames cannot spread to other areas of his garden.

Where he is growing native plants, such as pea flowers underneath mature gums, he keeps the plant density lower and makes sure there is not too much bark and leaf litter around them.

"So what I'm trying to do is actually grow them beneath the gums, which is their natural habitat but not to the density where it actually causes a serious risk of dense plants causing a fire," he said.

"What I often see in the [wider] area is that there is grass and then trees, but no understorey shrubs which are so often for the local wildlife and insects and the birds.

"So I'd encourage people to plant more of those understorey shrubs but be guided by expert opinion on how best to plant them without increasing the risk of fire."

The Country Fire Service and other authorities are predicting a hotter and drier fire season after three years of wetter and cooler-than-average summers.

"We have high fuel loads across the state and they're drying out rapidly," CFS's director of community resilience, Alison May, said.

"With the above-average temperatures, we're also seeing really high evaporative stress in the soil already."

But conditions are not like the catastrophic 2019-20 summer that saw disastrous bushfires in the Hills and on Kangaroo Island.

"In seasons like the 2019-20 fires, that was off the back of drought conditions and that's not what we're looking at for this season. Potentially next year given the long-range forecasts," Ms May said.

The Adelaide Hills is not one of the areas predicted to have an increased risk of fire by the Australasian Fire Authorities Council (AFAC).

Instead, the fears are for the mid-north and the Murray Mallee, where flooding has led to a boom in vegetation growth.