Fire: Friend or Foe?

a hollow tree burnt in the past

Fire is a way of life in Australia and many endemic species have evolved to benefit from fire. Some species only reproduce after fire, others are given the chance to grow after fires eg. understory plants which may not have enough space or light previously. Problems may occur when the time period between fires is too short, too long, or weed species have taken over and there is too much flammable material available. Fires may burn too quickly and intensely for animal and plant species and cause irreparable damage.

the burnt area viewed through a burnt out tree

Five weeks ago, on the night of Sunday 4 March a fire was deliberately lit at Star Swamp, a bushland reserve near where I live. This followed another deliberately lit fire in nearby bushland on West Coast Hwy in Marmion.

About 35ha of bush were destroy[ed] by the fire, which continued to burn throughout the day [Monday]. A FESA [Fire and Emergency Services Authority] spokesman said investigators believed the fires were deliberately lit by the one person. [1]

extinguish arson

Subsequently a second fire was lit on Tuesday 6 March in Star Swamp. The TV news that night said all the fires were arson. The following week Perth experienced a significant heatwave and

an extreme fire danger warning [was] issued for the state because of temperatures above 40 degrees combined with gusty winds. [2]

the path which acted as a firebreak. Further on the path was not wide enough and the fire jumped across

I haven’t been to Star Swamp since I was a kid. I took Sheeba the dog there a week after the fire to see the damage and I relived my childhood walks in the reserve. It was very hot, but I slip, slop, slapped and set off. I went in the Groat St southern entrance and didn’t know how long to walk before the burnt area. It was just like I remembered: paperbarks, insects clicking and the sun beating down. At one stage Sheeba acted very scared, like she heard thunder. I didn’t know why she was acting jittery and wanting to turn back, then we came to the burnt area. Sheeba must have smelt it before I saw it and decided this isn’t good, I’m out of here. I was oblivious.

the unburnt green in the middle was a swampier area at the edge of the fire and so was protected from the flames

The fire stopped burning a week ago, but Sheeba didn’t feel safe. I took some photos, felt shocked by the silence, then decided it was too awful and left. I only walked about 15 minutes in, but Sheeba ran the whole way back. Usually she stays close and runs back to me when I walk too slowly, but this time she only stopped far ahead, looked back to make sure I was following, and kept running. Always take a faithful friend when exploring uncharted territory.

the start of the burnt area. The green in the background is on the other side of another path which framed the burnt area

The WA Department of Environment and Conservation (and owners of private property) undertake controlled burning during winter to prevent out-of-control summer fires. Even so, there’s disagreement about how often or whether this should be done. After the Star Swamp fire, local resident David Pike, from the Friends of Star Swamp Bushland said,

The area will take more than a decade to recover. Some of the banksia trees in here that need about 15 years between fires to set seed, they’re killed by the fire, the seed drops, they grow up, they’ve got to set seed again. [3]

when I first saw this Zamia I was sure it was dead, but it will resprout

This was a particularly intense and damaging fire, but David Pike didn’t mention the reason some banksia are setting viable seed is due to the fire. Of course, this fire was deliberately lit and the negatives outweigh the positives. Ben Croxford from Nuts about Natives said,

A fire at any time of the year is likely to advantage some plants and animals and disadvantage others, depending on so many different factors. There are some amazing examples of regeneration following fire near my work which was burnt in the recent Dwellingup fires…For these plants a hot summer fire was what was needed, a slow winter burn would not have been any where near as good. [4]

Banksia attenuata flower in summer

There are many species of banksia. The two most common at Star Swamp are Banksia attenuata and Banksia menziesii which flower at different times of the year (B. attenuata in summer, B. menzesii in winter).
Banksia at Star Swamp Bushland

Many banksias evolved to survive fire. They don’t have a long life span, about fifteen years, and seed of some species must endure a fire to germinate. An intense fire could kill the parent banksia but provide space for seed to germinate and grow into mature trees. A less intense fire may allow viable seed set and the parent banksia can resprout from lignotubers or epicormically and have many more reproductive opportunities.

seed cone of Banksia menzesii

Since white people arrived in Australia we changed the niche banksia carved out. We cleared lots of banksia woodland, ended burning by indigenous people, and introduced invasive species which compete for land and other resources.

Local councils, Bushland Friends Groups and conservation organisations help to counter these problems by replanting native species to revegetate bushland areas. There are many species we’ve sent to extinction because we changed the environment they evolved to exploit. Perhaps we can make sure all banksia species survive and don’t join their fallen comrades.

=^.^=

References

  1. Perth Now (2007) Fire at Star Swamp.
  2. ABC (2007) Heatwave in Perth.
  3. ABC (2007) Star Swamp Fire.
  4. Croxford, Ben (2007) Personal communication.

3 thoughts on “Fire: Friend or Foe?

  1. there was another fire in star swamp on 20/12/2007, the day i’m writing this. i dont know if it was deliberately lit or not but it looked pretty bad as you could see it from the woolworths staff window at karrinup shops.

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