Blue Mountains bushfires: Why do they happen?
Blue Mountains bushfires, such as those that have burned in Blackheath, Mt Wilson and the Grose Valley, are a key part of the ecosystem. The eucalyptus trees of the Blue Mountains have evolved to live with fire
Bushfires strike the Blue Mountains, a popular escape from Sydney, on a regular basis. The 2020 Blue Mountains bushfires destroyed trees across a particularly large area, with the Mt Wilson and Grose Valley fires particularly dangerous. But there are big Blue Mountains bushfire seasons every few years.
The important thing to realise is that bushfires are a natural occurrence. The ecosystem of the Blue Mountains regards fire as an essential ingredient, not an unwelcome interloper.
7 Blue Mountains experiences you should pre-book
- Scenic World tickets – combine dramatic train rides, cable cars & forest walks.
- The Blue Mountains hop-on, hop-off bus – get around Katoomba and Leura’s top sites hassle-free.
- Guided stargazing with an astrophysicist – learn how to read the clear night skies.
- Give canyoning a try – jumping, climbing and sliding through Empress Canyon.
- Take a half day abseiling adventure – in the Blue Mountains National Park.
- Indulge in a local produce tasting experience – with beers, wines & meats.
- Get adventurous – on a 4WD tour to the world’s second largest canyon.
Blue Mountains bushfires: Flammable eucalyptus trees
This is because of Australia’s unique trees – the eucalyptus family. These trees don’t shed their leaves every year – they shed their bark. And it’s the only country in the world where you smell the leaves rather than the flowers. The oils in the eucalyptus leaves produces the well-known scent.
These oils are also highly flammable. And that’s deliberate.
The geology of the Blue Mountains, evolution of the eucalyptus trees and bushfires of the Blue Mountains are intertwined. Around 150 million years ago, the ocean floor lifted up creating a series of plateaus. These plateaus are now know as the Blue Mountains.
6 top Katoomba experiences to book in advance
- Connect the key sights in Katoomba and Leura the easy way – on the hop-on, hop-off bus.
- Discover your adventurous side – while canyoning at Twister and Rocky Creek.
- Indulge in NSW-sourced wines, beers and tasting platters at Echo Point, while overlooking the Jamison Valley.
- Combine canyoning and abseiling on a full day adventure.
- Explore the Jamison Valley from all angles – with the trains and cable cars of Scenic World.
- See ancient Aboriginal rock art – and the views other people miss – on a 4WD adventure.
Lightning strikes in the Blue Mountains
Over time, iron formed in rich layers within the sandstone. This attracted hefty amounts of lightning – the Blue Mountains region attracts 100,000 to 200,000 lightning strikes per year.
Nature adapted to this, and a new genus of tree was born. Eucalyptus trees are designed for lightning, and fire. The oils in the leaves go up in flame very quickly, with the resulting fires shooting through the canopy. This moves the fire on as quickly as possible, theoretically protecting the individual tree.
The bark is shed quickly for the same reason – the fire finds it hard to get a hold on the new, smooth bark.
Eucalyptus leaves also regenerate remarkably quickly. They have to, in order for photosynthesis to occur and keep the tree alive. It’s why areas that bushfires come through can seem fine a year or two later.
The rest of the ecosystem has adapted to this. Wildflowers have evolved to grow under the gaps of the canopy that the fire has ripped away.
The best Katoomba accommodation options include the surprisingly affordable Blue Mountains Heritage Hotel, the pool-equipped Skyrider Motor Inn and the rather grand Carrington Hotel.
Human impact on Blue Mountains bushfires
The problems arise when humans attempt to stop the fires. The landscape relies on mild fires coming through every four or five years. Where people prevent this from happening, leaf litter builds up, and when fires finally do take hold, they can be devastatingly ferocious.
For more information on fire safety, visit the New South Wales Rural Fire Service website.
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