The study, commissioned by Hort Innovation for Turf Australia, and conducted by the CSIRO in collaboration with international sustainability consultancy GHD, involved 221 attempts to set couch, buffalo and kikuyu turf alight. Only dead grass, with extremely low moisture content, burned.
Paul de Mar, natural resources and bushfire management consultant with GHD, says the study showed that “watered and live turf lawns are not combustible under natural conditions associated with bushfires”.
“Even lawns that are drought-stressed but provided with just enough water to keep them alive, are highly unlikely to ignite and sustain fire spread,” he said.
De Mar says the study backs up the long-held operational knowledge of firefighters that lawns are useful to mitigate fire spread, and provide defendable space near houses.
‘Watered and live turf lawns are not combustible under natural conditions associated with bushfires.’
Paul de Mar
In previous droughts, gardeners have been advised to use precious water collected in the shower and sink to keep mature trees alive, but the value of living lawn in mitigating fire risk will make future decisions on where to spend limited water resources an even tougher one.
Fire-retardant trees – those with soft, fleshy leaves; non-fibrous bark; and low levels of volatile oils – can also help slow the spread of fire by capturing flying embers. Native rainforest trees, including lillypillies, figs, and native frangipani Hymenosporum flavum, are good choices, and so are exotic garden favorites such as frangipani, hibiscus and camellia. As Give me a home among the lillypillies doesn’t scan, I’ll leave the re-write to John Williams.