The word ‘bushfire’ is usually followed by the phrase ‘hectares of bushland destroyed’.
Fires can have devastating impacts on human lives, homes and communities, however it is a mistake to see most fires as destroying bushland. Fire is an agent of change rather than destruction, setting in chain a remarkable process of recovery and renewal without which many of our local plants and wildlife would not survive.
The aftermath of a wildlife or hazard reduction burn illustrates the uneven pace of environmental change. The virtually instantaneous fire event utterly transforms the landscape, followed by years of gradual shifting and maturing vegetation communities.
I spent a couple of hours wandering around part of Royal National Park that was burnt a fortnight earlier. It was an intense burn, with most of the ground cover and scrub layer incinerated and heavy scorching in the canopy. The forest was dominated by Angophora costata, gnarled and twisted trees whose pink bark complemented the brown and black tones of the fireground.
Australian plants have many ways of surviving bushfire. Grass trees are only a metre or two high, well within the hottest part of the flame zone. Their outer stalks burn away, but closer to the trunk they form a dense sheath that protects the underlying tissue. Only a few days after a fire green tips start to appear amongst the charcoal and ash.
Another splash of green in the days after a fire is braken, new grown emerging from buried roots.
Other plants rely upon the next generation for survival through fires. Some drop hundreds of seeds each year, a few of which sift through the soil and into the buried ‘seed bank’. Seeds that germinate immediately after a fire have little competition from established plants. Tiny plants start appearing from the seed bank within a few weeks of sustained rain.
Some plants only release their seeds when directly impacted by the fire. Banksias have a large colourful spike of flowers, but produc few fertile seeds. The sparse seed capsules are embedded in the banksia cone and remain on the tree for years. The capsules open when heated, dropping the large seeds onto the ground.
Hakeas use a similar strategy, although each pod contains just two seeds. The tissues within the pods have distinctive patterns and colours, becoming obvious as they open to release the winged seeds.
Isopogon release a mass of small seeds from a dense cone after a fire. Each seed has tiny tendrils that catch the wind to disperse the seeds away from the parental tree. A week earlier I’d photographed an Isopogon at Muogomarra in the rain, and almost unrecognisable contrast to the post fire form of the cone.
Foliage holds a surprising amount of water and the desiccated leaves often remain ‘frozen’ by the passing fire rather than charred into ash.
Soon after a fire wildlife arrives to forage on the fireground. Yellow Tailed Black Cockatoos feed on the opening banksias, while predatory species such as Australian Raven, Pied Currawongs, Laughing Kookaburra and Sacred Kingfishers search for dead and injured animals.
Birds tend to be the first arrivals after a fire. Some use the open conditions to ambush passing insects or other wildlife arriving in the vacated territories. New Holland Honeyeaters can be found wherever they can foray after flying insects, providing a splash of colour and movement amongst the burnt sticks.
Bushfires generate huge amounts of particulate matter and create spectacular sunsets. I’m a bit addicted to photographing honeyeaters at sunset. A thick layer of smoke obscured the setting sun enough to include it in silhouettes without blowing out the highlights.