Australia has had a history of bushfires stretching back long before the English invasion. There seems to be little doubt that the fire related activities of Aborigines have had a substantial effect on local ecologies and the species that have survived and gone extinct.
This post consists of a number of fire related statements written as a prod to discussion.
- A number of factors contributed to the extent and severity of the NSW/Qld 2019 fires: These included:
- The positive Indian Ocean Dipole (IOD). Which increase rain in Africa and delays the end of the Indian monsoon while reducing the flow of Late monsoon and Indian Ocean Dipole key factors in current Australian weather and fire crisis
- Unusually warm, dry conditions earlier in this season than usual.
- Warmer conditions reduced the time available to reduce fire hazards for this summer.
- We don’t know to what extent the items listed above are a one off coincidence as distinct to a long term change in weather patterns.
- Fires and the way we manage fires and fire protection can have a marked effect on both the built and natural environment, the extinction emergency and weather patterns.
- Australian plants, animals and ecologies have evolved to deal with the effects of fire in various ways. At one extreme there are plants etc. that are killed by fire and others that need periodic fires to survive and compete. (Think plants that need fire for their seeds to germinate and the burning of other plants to give their seedlings fertiliser and a clear space to grow. Coastal heaths and wildflower zones often depend on periodic fires to thrive.)
- Some fire resistant plants have leaves etc. that burn strongly and destroy competing plants. Increasing the frequency of periodic burning to reduce the build-up of flammable material will favour these fire resistant species and may actually make fires worse.
- When spinifex burns it leaves the ground bare. It grows again starting with small clumps that are too small and far apart for a fire to propagate. After a number of years the clumps expand until they are close enough to propagate. Once this has happened a lightning strike or whatever can start an intense spreading fire over a large area.
- Some animals that live in spinifex country need amix of mature spinifex clumps that they can hide in and get out of the sun in during the day and less mature spinifex areas where they can feed at night.
- Firestick farming of spinifex involves lighting mature patches when the wind is blowing towards nearby immature patches that are big enough to stop the fire. The result over time is a moziac of small patches of varying maturity that provides hiding places in old spinifex close to feeding spaces in younger spinifex for the small animals that live in this type of country. Aborigines and hawks hunt some of the animals that are disturbed by the fire. (The fires may also encourage plants that Aborigines use.)
- The small fires associated with firestick farming make it easier for small animals to escape the fire and reach safety.
- Where Aborigines are no longer looking after the country older patches that have not been burnt link up. The result can be much larger fires that are harder to escape, reduce the total length of boundaries between older and newer growth and reduce the number of animals that the system supports.
- In some cases grazing practices rather than fire might be used to create the mosaic. Recently grazed areas will reduce fire intensity, slow down fire fronts and provide refuges for people and animals trying to escape fires.
- In the parts of Arnhem land that I was familiar with firestick farming takes a different form. The dry long grass from the wet season is burnt early in the dry season when the soil still contains some moisture. The moisture means that green shoots will sprout after the fire and attract animals that the Aborigines hunt. Burning is also done to make it easier to move around during the dry season. (Wading through long grass is hard work.)
- Mosaics are all very well but many animals need connected country to allow them to travel around to seek mates, adapt to climate change etc. Poorly designed connections may help fire travel around too. Bent shapes may reduce the risk by allowing fire to go only so far before it needs to change direction and burn into the wind.
- Other Aborigines will have had their versions of firestick farming and fire management. This will have affected the countryside and made changes to the species that thrive and struggle.
- Recovery can be rapid a few weeks after bushfires as species that benefit from fires take advantage of the circumstances that suit them.
- Since Aborigines arrived the world climate has changed to include periods of ice ages etc. It is not just human activity that has formed the Australian countryside.
- We can learn from the ways Aborigines used and looked after the land. However, keep in mind that what they did was about supporting their lifestyle and may, over time, have reduced the lands capacity to support people as well as reducing environmental variability.
- Fire has a role in the competition between grass and trees. Grass fires will kill young trees but not more advanced ones. Frequent grass fires favour grassland. Less frequent fires may allow the forest to take over what used to be grassland.
- Healthy trees pump moisture into the atmosphere continuously except under very very dry conditions. This moisture increases the chance of rain. The sucking up of this moisture can stop the level of the saline water table rising. Strategies aimed at reducing fire risk need to understand that trees are more than just fuel to fires.
- Some greener, lusher plants that don’t burn easily may help slow down or stop fires. (Think rain forest trees.)
- From a conservation point of view fire policy should aim at protecting iconic places and species as well as supporting environmental diversity and limiting the damage caused by bushfires.
What should happen now? ( Dec 2019)
- Continue fighting fires:
- Look for ways of increasing the resources being used to fight this lot of fires.
- Find the generosity to provide some compensation to volunteers who have been fighting the fires and businesses affected
- The size of the fires means that we are unlikely to have another big one in the areas where the fires occurred. Time to think, do the research properly and come up with good plans.
- The response to the Dec 2019 fires needs to consider both:
- The overall problems of fighting such a widespread and prolonged fire emergency.
- The whats, whys and contributing factors behind what happened locally.
- What worked locally? Action to reduce risk, make it easier to fight fire or reduce damage.
- There is a real risk that post fire discussions will get bogged down into a war between those:
- Who think it is all about climate action
- Who want to shut down or modify national parks.
- Want to blame the Greens etc.
- Who see opportunities to do things like harvest more trees, get some free grazing in national parks etc.
- Investigation needs to get down to individual fires. Some of the causes and actions will be quite local.
- Questions that need to be asked include:
- What can be done to make homes and buildings more fireproof.
- How many lives would have been saved by better shelters?
- How many problems related to the difficulty of getting out via long roads etc once the evacuate order was issued?
- What do we do to increase air moisture levels? (More trees? Forests stretching from the coast? And??
Looking forward to suggestions.