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The destruction of Cabbage Tree Creek

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Felled trees line the side of Palm Track in the name of asset protection (Image supplied)

Natural disaster and manmade destruction is ruining the serenity of one of Australia's hidden gems, writes Dr Peter Fisher.

DOWN IN FIRE-RAVAGED East Gippsland, there’s a botanical wonderland along a creek awaiting its pyro fate as the summer rolls on. It’s an isolated population of cabbage-tree palm separated from the main distribution along Australia’s east coast by some 300km at Durras which could well have perished by now due to the Merimbula fire.

How did that disjunction occur? One account has it that their red berries were prized for ornaments and may have been traded among coastal tribes leaving a southern outlier. Another says there was once a more continuous distribution, but a rain shadow that developed after Bass Strait formed 8,000 years ago knocked out intermediate populations. In any event, their survival in a tract of warm temperate rainforest now hangs on a knife-edge.

A national disgrace

Last June, the botanical senior citizens who’d been hanging out at the Cabbage Tree Creek gig for nigh on 200 years had their serenity shattered by the whir of contractor’s chainsaws. They were at work down the track, clearing a wide swathe of trees on either side in the name of asset protection. This has provided a conduit for hot winds to dry out the warm temperate rainforest home, altering its homeostasis as well as providing a superhighway for herbivores like sambar deer (who target rainforest shrubbery) and wallabies to chomp on the cherished understorey of muttonwood leading to its eventual replacement by grass.

Harding Track in Mt Alfred State Forest cleared for FFM ground crews creating massive edge effects (Image supplied)

Over 200 trees were felled into the reserve, some of them mahogany gums, possibly 400 years old. Heavy machinery had gone into gullies and pushed debris right up to the edge of the warm temperate rainforest at the south-western end of the track on the bend just before the bridge near the picnic area. Numerous woodcutters descended upon the spoils shortly afterwards.

Cascade world

It used to be thought that rainforests don’t burn, but the recent contagion in Springbrook National Park arising from a lethal combination of drying out and an extremely hot fire has finally put pay to that proposition. A positive feedback loop  –  the hotter it gets, the drier it gets, the hotter it gets, the drier it gets and so forth – is long suspected of being an underpinning mechanism in cataclysmic wildfires. The sheer scale of the spot fire cascade as captured by thermal imaging of the Mallacoota fire is daunting, to say the least, with a lack of moisture in the first 15cm of soil and the equivalent air layer above thought to be a contributory factor.

What does the science say: Tipping points and positive feedback loops

Beyond that, there’s a possibility that tipping points, long talked about, are being approached — where, rather than things getting gradually and linearly worse, a system flips to a new state, with less predictability and often irreversibly. As visiting Penn State University climate scientist Michael Mann notes, there are processes playing out in nature that aren’t actually contained within our models.

One of these was observed over Mount Riddell near Healesville on Black Saturday when the Kinglake-Murrindindi blaze generated its own thunderstorm and lightning, further fuelling the contagion, re-experienced a decade later in southeast Australia and astounding the media that a fire could actually create its own weather. Another idiosyncrasy is fire tornadoes powerful enough to flip an RFS truck on its back with tragic consequences.

These crazy, wildly improbable happenings serve to emasculate tenets that grew up and matured, along with their proponents, in a previous climatic era — measures like back burns and fire breaks live on in fuel and risk management. Yet, climate scientists are now saying that wildfire models need to be revised.

Evidence-based strategies go missing

Permanent fuel breaks, fuel management corridors and the like are trappings of a management regime that doesn’t appear to have learnt a great deal from scientific observation. North of the border, Rural Fire Service boss Shane Fitzsimmons has done his homework noting that hazard reduction is ‘not a panacea for bushfire risk and has “very little effect at all” on the spread of fire in severe or extreme weather’

An earlier study of French Island forests came to largely the same conclusion, namely:

An open under storey is not necessarily the result of frequent burning... [and] that frequent hot burning by settlers in some locations gave rise to a dense growth of trees and shrubs. This finding is further butressed by University of Melbourne fire researchers: ...evidence shows increasing the frequency or area of controlled burns does not necessarily reduce the bushfire risk.

Despite swathes of such evidence, the idea persists, even being suggested by Scott Morrison as an alternative to emissions reduction.

Since 2009, the area of Victoria that has experienced recent fire, due to planned burns or wildfire, has significantly increased (Source: Victorian National Parks Association)

Ecological experimentation

The inference is that plant, insect and animal diversity is being altered in some way or other — maybe profoundly. No better place to look than Cabbage Tree Creek where the clearing of Palm Track was undertaken in the name of intense fire protection around communities, or “asset protection” for the township of Cabbage Tree Creek — comprising a few houses and a store presumably selling postcards of the palms.

Widening this and other tracks to the width of the highest adjoining trees to meet the safety of Forest Fire Management (FFM) ground crews amounts to islanding large parcels of bushland, preventing free gene exchange between animal populations like yellow belly gliders and sugar gliders not to mention forming a path for invasion by herbivores. It would also have huge edge effects and predators just love open tracks.

Yet advocacy of fuel management corridors through vast tracts of public land to break up large fires is once removed from the reality of hot fire behaviour witnessed with the Mallacoota blaze. 

A year-on-year cycle of burning/clearing might also be weakening ecosystem resilience to an extent that an “event” could send it over the edge to a species-impoverished state. Such miseries are known to have been visited on lakes, oceans, coral reefs, forests and arid lands. If this is happening, then like extinction debt we may not know of the effects for upwards of a generation and by then it could be obscured by the interplay of global heating apropos of the twin crises of climate and extinction emergencies.

What’s in an asset?

This autumn, the surrounds of Cabbage Tree Creek will be put to the torch for a planned 2,000-hectare asset protection burn compounding the damage of last June and adding to our national emissions tally. It clearly poses the question of what “asset” is being protected here. Maybe the store, but certainly not an outstanding warm temperate rainforest harbouring a population of 200+-year-old palms with First People’s connections uniquely set within a crossover between warm and cool temperate flora and fauna.  

Across the border, a conservative NSW government in the midst of a state of emergency to fight the fires on its southeast coast marshalled all possible resources to save the Wollemi pines, which it declared a national asset.

No less, a resolve is needed to protect this other vestige of an ancient wilderness.

Dr Peter Fisher is an Adjunct Professor at the School of Architecture & Built Environment, Deakin University.

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