Fire and the Central Highlands

The forests of the Central Highlands, as with most forests in Australia, are dominated by Eucalyptus trees. The genus Eucalyptus rose to ‘superdominance’ with the gradual drying out of the continent over the last few million years. Eucalyptus is uniquely adapted to fire, with individual trees regenerating through woody reserves at the base (lignotubers) as well as by resprouting from the trunk (epicormic growth).

Whilst climate remains the major reason why Australia’s vegetation came to be dominated by fire adapted Eucalyptus, it remains contested how much the arrival of humans on the continent some 50,000 years ago contributed to this change. In part, this is because evidence of any intentional burning regime prior to European invasion is fragmentary.

When Cook sailed up the eastern coast of Australia in April 1770, he saw ‘several smooks along shore before dark and two or 3 times afire in the night’. After the invasion, several Europeans noted how the land around Warrane (Sydney) had a park-like appearance, and in places ‘chequered by woods and lawns’. This fragmentary evidence has led to the idea that Aborigines burnt the bush repeatedly and extensively to manage the country. The application of ‘firestick farming’, as it is called, was done to reduce fuel loads as well as create lush grass for favoured prey species such as kangaroo and wallaby. One historian even described the entire continent of Australia as being managed like an English estate – the ‘biggest estate on earth’ – although one with many different managers. 

In contrast, it has been pointed out that the scientific evidence of the First Nation people burning enough to impact the vegetation of the continent is minimal. In addition, with language being ‘the body in which Aboriginal culture lives’, it is notable that the ten languages groups across south western Victorian lack words to describe purposeful burning of forests. In his description of the fire history of the Australian Alps, Dr Philip Zylstra, an academic at the University of Wollongong, notes how instead of ‘simple, savage fire’, the First Nations peoples used ‘an extraordinarily complex system of controlled burning and exclusion’. For this reason, it is probably safer to say burning by First Nations people was more likely of a limited, mosaic type rather than broadscale burning across the landscape, not least because of the very real danger represented by an uncontrolled bushfire to the lives of First Nation peoples. 

HOW CENTRAL HIGHLAND FORESTS ARE FIRE ADAPTED

The forests of the Central Highlands are characterized by high rainfall, which would render fire less dominant in shaping their history. This is particularly true for Mountain Ash trees (Eucalyptus regnans) of the wet forests. Unlike other Eucalypts, they cannot regenerate either through underground lignotubers or epicormic growth. Yet paradoxically, occasional intense fires are necessary to this species' continued existence. One reason is that any seeds released from trees without a fire are known to be eaten by hungry ants. Only with the immense seed fall following an intense fire are the ants sated, allowing seedlings to germinate. They then take advantage of the increased light and nutrients in the ash bed. 

In the damp forests of the Central Highlands, dominated by Messmate (Eucalyptus obliqua), Mountain Grey Gum (Eucalyptus cypellocarpa) and Narrow-leaf Peppermint (Eucalyptus radiata), fire was probably more frequent – all these species, as individual trees, can regenerate after burning. But like the Mountain Ash forests, these mixed species forests don’t welcome frequent conflagrations.

FIRE SINCE THE EUROPEAN INVASION

The arrival of Europeans in the Kinglake area from the 1830s disrupted the ancient cultural practices of the First Nations people of the area– the Taung Wurrung and the Woi Wurrung – who knew the forests and the animals and plants which live there. European practices of road building, clearing and farming fragmented the landscape. The stage was set for catastrophe, with humans living in fixed settlements adjacent to forests. Major fires occurred in various parts of the Central Highlands in 1851 as well as 1939, 1983 and 2009. 

The 2009 Black Saturday Fire remains the worst in term of lives lost in Victoria. It affected the Central Highlands particularly severely. Around midday on February 7, a fault on a power line at Kilmore East sparked a fire that spread quickly to the south east, fanned by hot temperatures and strong winds. A wind change in the evening pushed it towards Kinglake and beyond. This map, from an excellent article in The Age of 2019, shows the full extent of what was called the Kilmore East Fire. This would go on to create another major conflagration to the east, called the Murrindindi Fire.

FIRE MANAGEMENT ZONES

A Royal Commission following the Black Saturday Fire recommended a change in the way state forests were managed. This led to the creation of Fire Management Zones. The clues for what these zones aim to achieve lie in their names: Asset Protection Zones, Bushfire Moderation Zone, Landscape Management Zone, and Planned Burning Exclusion Zone. The map below, from a VicForests document, shows how these zones are applied across eastern Victoria.

 (FMU = Forest Management Unit.)

The category of interest to us, your friendly neighbourhood environmental group, is Bushfire Moderation Zones. And we’ve just concluded a court case against VicForests, as we allege that VicForests has exceeded the area legally allowed to be logged in this zone. The limits to logging have been mandated by Government in the Code of Practice for Timber Production, which regulates logging in our state forests.

Many scientific studies indicate that logged forests are generally more flammable than established forest. Once logged, a forest area ‘dries out’ as a result of exposure to sun and wind. Moreover, the trees are of a more uniform height, so fire can travel along the crowns more readily.

THE FUTURE OF FIRE

The bushfires of 2019-20 were shocking in their extent and intensity. A scientific study (described here) indicates that climate change was a factor in this, and with carbon pollution continuing every day, our bushfire seasons are only going to get worse. The number of dry lightning storms has also increased since about 2000, which ignite these drier forests.  As well as reducing greenhouse gas pollution, we need to preserve the intact native forests, since carbon storage is among the many ecosystem services they provide. Such forests also provide a natural barrier to fire, with more moisture retained within them, and fire travelling less quickly amongst trees of uneven height. 

And that is another reason why we fight to end native forest logging.