Wood chips pose a significant fire hazard. Photo: supplied.
Local farmlets have recently turned to using fermented Blue Gum wood chips for mulching to conserve water.
However, strong fire warning advice exists around the use of combustible mulch during bushfire season.
CSIRO research has examined the flammability of wood chips, which pose a significant fire hazard, especially fine wood chips, expanses of wood chips, or thick layers of wood chips.
They comprise fuel for fire that can then travel along the ground and wood chips can ignite from both, heat or embers.
This can potentially lead to spontaneous combustion of the mulch itself and cause fire to spread.
To reduce fire risk from wood chips, CSIRO recommends avoiding deep, fine mulches near structures and suggests the use of non-combustible alternatives like sand, shells, pebbles, or gravel to create a defendable space of at least 5 metres around housing.
CSIRO also recommends reducing the overall size of any area that utilizes combustible mulch, separating combustible areas with non-combustible elements such as pathways or open spaces that can act as a small firebreak.
The CSIRO says mulched areas need to be kept wet during a bushfire, until the fire front has passed.
Fine light mulches smaller than half a centimetre in diameter should be avoided as they are highly flammable.
Also, when storing combustible mulches they should not be kept near structures or houses, “especially under or around windows, doors and subfloor structures.”
Non-combustible stone or concrete edging should also be used instead of timber, around mulched garden beds.
A spokesperson from the Department of Fire and Emergency Services (DFES) said the department has several guides available on its website regarding mulch use, and the design and maintenance of gardens, to lessen risks in bushfire prone areas.
DFES advice mirrors the CSIRO’s concerns, with DFES stating that vegetation near properties should be kept “at an absolute minimum and the space should be free from combustible items and obstructions.”
“It is best to avoid using flammable mulch around a building,” the spokesperson said.
“If using combustible organic mulch elsewhere, avoid fine materials, separate garden beds and keep the area small and irrigated where possible.”
Mulch fires are mostly likely to start when conditions have been dry for a while, humidity and moisture content is low and temperatures are high, the DFES website advises.
“With bushfire season just around the corner communities are encouraged to take action now to prepare their properties,” the DFES spokesperson said.
The spokesperson also encouraged property owners to make or update their Bushfire Plan via the app or website.
More information about preparing properties for bushfire season is available at the DFES website.
