Landscaping for bush fire safety
The Blue Mountains is surrounded by a highly bush fire prone World Heritage National Park. During a major bush fire, firefighters will be working to stop the fire from spreading, or guiding the fire to protect property and assets. A fire truck will not always be available to defend every home. Home owners are therefore encouraged to accept and manage the risk around them even if you live in an urban area some distance from bushland.
A well designed garden can provide a 20m circle that will allow you and fire fighters to safely protect you and your home. It is crucial that you consider how a fire truck can access your property, how much fuel load you have an your property, and it ideally will allow the fire truck to enter and leave via multiple paths for fire fighter safety if the property becomes indefensible. This brochure provides information that will help to plan, prepare and maintain your garden areas.
Bush fires - How they affect your property
There are four main ways that bush fire can impact your home.
1. Wind during bush fires can be extremely strong, even gale force. It can throw debris, branches and other loose items into your property and house up to several hundred metres from the main fire. Wind causes damage to buildings, especially windows and roofs and can create openings that make your home vulnerable to ember attack.
2. Burning embers carried by extremely strong winds can occur up to 30 minutes prior to the fire front, and for several hours afterwards. Embers enter through broken windows, gaps in and around walls, under roof cladding and doors. They can lodge in decking, guttering leaf litter, windowsills, open floor joists and fencing, as well as firewood piles.
This is the main reason houses catch fire during a bush fire.
3. Radiant Heat is the heat that spreads out from the fire. It can be intense enough to crack windows, allowing embers to enter your home.
4. Direct Flame Contact occurs when materials and vegetation close to your home catches alight. The length of time this burns depends on the amount of fuel available.
Fuel is anything that can burn.
What are bush fire conditions?
In extreme bush fire conditions all plants will burn, though some burn more easily than others. These conditions are a combination of fuel levels, low humidity, high temperatures, drying winds, low soil moisture and flame or ember contact.
However, there are certain characteristics of plants and landscaping that will provide improved protection for your home.
We'll talk about these later...
What are the features of your property?
• slope of your land - fire travels faster uphill than downhill and along flat ground;
• aspect of your property - a north/westerly aspect may be more vulnerable to bush fire;
• prevailing winds - direction of possible ember attack and fire;
• local native vegetation - plant communities and individual species vary in flammability;
• bush fire history of the area - bush fires usually occur in the same area and generally come from the same direction as they have in-the past.
How can you design your garden to reduce it's vulnerability?
Remember this can be a normal looking garden, with lawns for children and pets to play on, areas for BBQs with friends and vegetable and herb beds.
You may need to consider some changes to your garden.
A garden planned for bush fire safety will provide shelter from radiant heat for your home as well as garden. It may reduce the intensity and spread of the bush fire on your property and surrounding properties. It slows the wind speed, reduces and deflects flying embers and flame contact with your home is less likely.
Planning a space around your home allows you to protect yourself and your home if your area is impacted by a bush fire.
Consider areas of vulnerability and set up sprinkler water points. Wooden structures, water tanks, firewood piles, decking and open verandas are where a sprinkler or water spray may well save your house and property. A generator is also crucial as power may not be available when a severe bush fire impacts your area, rendering your household water pump useless if you do not have mains water pressure.
Where do you start?
Trees - use them to your advantage.
Some people think the safest thing to do is to chop down all the trees around their home.
But wait - this isn't the solution....
Trees can protect you and your home from strong winds, radiant heat and flying embers.
Trees may save your home in a bush fire.
In a hot, dry summer, trees are likely to be the greenest and wettest things in your garden.
A wind break will help either to protect your home from the impact of a fire or lift the wind-born embers over your home. Ensure that the fuel load under the trees is minmised by hand clearing. You want your trees to carry the hot fire laden winds and embers up and over your home.
But you don't want the trees to catch fire; if they do catch alight, you don't want them to spread the fire to other trees or your home so....
Break up the canopy
Incorporating a wind break in your garden design by planting trees singly or in small clumps - not in a continuous band. This is best if you allow 50 - 60% of the wind to penetrate the trees.
Trees will reduce the strong winds, slowing the fire, and can trap the flying embers preventing them from reaching your home. For this to be effective, you need to get rid of the fuels in and around your trees.
If your home is close to the bush, make sure there is a good break in the tree canopy between the bush and your own trees. You might like to seek advice from the Rural Fire Service about what trees should be removed or opened.
How do you choose the right plants?
Remember in extreme bush fire conditions all plants will burn: some are very flammable while others may provide good protection for your home. Those that provide the best protection in a fire contain plenty of water or salt in their leaves and low - or no volatile oils and don't produce too many dead leaves and twigs.
Choose plants that have smooth or thick bark; dense foliage; no dead material within the foliage and have space between the lowest branches and the ground.
Some trees produce less fuel than others and are a better option in a bush fire prone area. While some native shrubs such as acacia, grevillea, callistemon tea tree and banksia do have a tendency to burn well, if planted correctly and with minimal fuel load in its proximity, these will not cause any heightened danger. A well watered garden will help to slow and moderate radiant heat during a fire attack. Tree ferns are an excellent choice in your garden as these not only don’t burn that well, but will revive quickly after a fire event.
Seek advice before you plant.
Before you choose plants ensure they are appropriate for where you live; consult Killibinbin Native Nursery and we can give you specific advice for your garden.
Non - local plants, when grown in a different area, can become weeds and a major environmental issue.
What about my vegetables?
A well watered vegetable garden makes a good green fire break. If you can, locate it on the side of your home that is most at risk from fire.
Fruit trees can be incorporated into your wind break.
How can we make a safer design?
Give some thought to where plants and structures are placed in your garden so they can increase your safety in the bush fire season.
The path a fire will take will depend on the fuel in your garden. It doesn't spread easily over areas of low fuel, so try to have these areas nearest your home. Driveways, well watered mown lawns, gravel paths, paved areas, swimming pools, vegetable gardens, ponds, water tanks and dams can be low fuel areas. Keep all of these areas free of fallen and wind blown fuel during the bushfire season.
Vines and creepers growing over a pergola attached to your home will be harder to monitor during a fire.
Design into your garden non-flammable structures like masonry walls, earth mounds, terracing and metal fencing to protect your home and garden from radiant heat. These structures will slow the fires progress especially on sloping land.
Beware of brushwood and split bamboo screens as these are highly flammable.
Water tanks, swimming pools, ponds and dams can be used during a fire to dampen areas around your home. A petrol or diesel pump with hoses in your pool or static water source may help you to be able protect your property during a bush fire.
Remember locked gates can prevent you, your neighbours and fire fighters gaining access in a fire emergency.
What can you do to improve your situation?
Around your garden, the most important part of preparing for the bush fire season is to remove any fuels that can carry fire. Rake up the fuel, dig it in or pick it up with a mower or leaf blower.
This can be a job for the whole family. During the bush fire season, plan to use the first weekend of each month to remove rubbish, leaf litter and any dead garden material from under trees, under your home or deck, in the gutters, twigs and branches, long grass, stacks of timber, fire wood or rubbish. Also get rid of hanging bark and dead sections of hedges.
Keep grass short and green.
Some trees produce less fuel than others and are a better option in a bush fire prone area. Those trees that produce a lot of fuel or litter almost always catch fire because the dead leaves and debris under them are burning.
Liquid fuels (such as lawn mower fuel) can be stored in a shed or garage in a sealed approved container. Leave LP gas cylinders attached to your home.
Keep mulched garden beds damp by choosing heavier mulches, or gravel; maintain a minimum amount of mulch around plants; rake and remove extra mulch and dead vegetation