General Information
Why We Are Concerned »»
Bushfires are Getting Worse
What do bushfire records show? Every year the southwest of WA is experiencing larger and more intense and damaging bushfires. All the factors leading to the terrible bushfires in the Eastern States in recent years are present in WA. At the same time, the Government’s bushfire damage reduction program has been allowed to slip to danger level. There are two critical problems. The first is a massive buildup of bushfire fuel in public and private forests. The second is that the resources available to fight fires are in decline. On-ground fire fighting strength of the main Government agency, DEC (formerly CALM), is now half what it was 25 years ago. The volunteer bush fire brigades are also declining in strength, partly due to demograohic changes. Waterbombing aircraft and helicopters can assist at a fire, but are not a substitute for on-ground firefighters.
The graph below shows the area of land managed by DEC in the southwest of WA that has been affected by wildfire over the period 1951-2008.
The graph clearly shows that after the 1961 fire season, the area affected by wildfire was very low for the next 25 years, due to comprehensive fuel reduction programs instituted by the then Forests Department. Since the formation of the Department of Conservation and Land Management in 1985, resources were progressively redirected away from the southwest to other areas, the fuel reduction program declined and the area of wildfires began to mount. The situation has not changed since the formation of DEC.
The reason for this is simply that the public forests of the southwest have been allowed to accumulate large areas with heavy fuel. Up until about 1990, the majority of the jarrah forest was burnt by a prescribed fire every 5-7 years (5 in the west, 7 in the east, due to differing fuel accumulation rates). Now there are large areas of this forest over 15 years since the last burn. Over half of the jarrah forest carries fuel older than 6 years. That means that about half the forest will now support a crown fire. This is a very dangerous situation.
There is a parallel situation in forest on private land. For about 25 years after 1961, the then Bush Fires Board had a vigorous program of fuel management carried out through the volunteer bush fire brigades. Shire councils were made responsible for fuel management in their region and did a good job of maintaining low fuel loads. Now many councils are failing to fulfill these obligations. The functions of the Bush Fire Board were taken over by the Fire and Emergency Services Authority (FESA), which has a prime focus on suppression, not fire prevention through fuel management in rural areas. As a result, there are now high fuel loads on much of the private forest land.
Needless Losses, Excessive Costs
Every fire season we see graphic TV scenes of houses burning and people losing all their belongings. With proper planning and adequate land management, this need not happen. We all suffer financially for these losses in the form of higher insurance premiums. The solution is not to just throw more money at the problem, in the form of bigger and better (and much more expensive) helicopters. To do so encourages the fire suppression mentality, which always fails under extreme conditions, as well demonstrated in the almost annual Californian fire disasters. When the world’s wealthiest and most technologically advanced nation cannot control wildfires by relying too heavily on the suppression approach, there is no case at all for Western Australia to move further down that path.
Our Objectives
The Bush Fire Front has the following basic objectives:
- To ensure that DEC restores its fuel reduction burning program to a level that will provide effective protection to community and forest assets from excessive damage from wildfire. Taking into account the backlog accumulated over the last 15 years, we estimate that the annual area burnt needs to be about 300,000 hectares.
- To improve the commitment of all levels of government to better forest fire management. It is not just crown land where fire management needs to be improved. There are large areas of private land in a similar situation.
- To promote the adoption of a best practice approach to forest fire management in Western Australia.
The Impact of Bushfires »»
Although the primary focus of the Bushfire Front is on forest fire on crown lands in the south west part of Western Australia, fire management concerns private land as well, both rural and urban. If city dwellers thought they were not concerned about bushfires the 2003 Canberra disaster and the succession of disasters around Sydney since 1994 have demonstrated that they are not immune from bushfire damage.
Bushfire basics- The Fire Triangle
The “Fire Triangle” illustrates the three essential components of a bushfire: heat, oxygen and fuel. If any one of these three is missing, fires cannot start or keep burning. Fuel is the only element of the fire triangle which can be controlled by land managers. If bushland fuel levels are reduced before a summer bushfire starts, the fire will burn less intensively, will spread less rapidly, will cause less damage and can more easily be controlled by firefighters. This is the principle on which the practice of “prescribed burning” is based. Fresh oxygen is always being delivered to a bushfire by the wind and cannot be controlled. Heat cannot be usefully reduced in a summer bushfire even with helicopter water tankers. Pouring water on a fire is traditionally used by firemen in urban areas to put out fires in houses and factories where there is ready access to fire hydrants and mains water supplies. In a forest bushfire situation the huge quantities of water needed to put out a fire are simply not available. This principle is well understood and supported by science and field experience. In Western Australia a whole bushfire control strategy was designed around it, and practiced with great success from the 1960s to about the late 1990s. Records show that during these years, the number of damaging bushfires in southwest forests was greatly reduced.
But the system has been let slip. The State government is no longer meeting bushfire damage reduction targets, and is increasingly devoting funds to fighting fires after they start. This is necessary, but is only one aspect of an effective bushfire management program, and cannot succeed by itself, as has been amply demonstrated in New South Wales over the last 15 years.
A Regional Problem
The incidence and severity of bushfires in Australia varies from year to year. Generally, mild summers without extremes of drought, high temperatures and strong winds lead to fire seasons where there is little damage. Unfortunately, a sequence of such seasons can lead to complacency. Normally, severe fire seasons occur every several years, when most of the damage is caused. It is often said that 90% of fire damage occurs in 10% of the years. The bushfire issue cannot be confined to forest areas alone. It is a regional issue affecting crown forests as well as farms, rural towns, rural infrastructure, private native forests and private plantations. On crown land, such as State forest, National Park, Nature Reserve and Regional Parks, responsibility for fire management rests with the Department of Environment and Conservation (DEC). DEC has a good fire detection system, long experience in forest fire management, but inadequate resources of manpower or funding to meet its obligations. On private land it is the responsibility of local government to implement the provisions of the Bush Fire Act. Their principal responsibility is for the control of fire hazards by requiring removal of fire hazards where they exist on private land. They also support local volunteer Bush Fire Brigades. In contrast to the general position in the 1960s and 1970s, following the disasters of the early 1960s, some rural Shires are now not as committed to bush fire prevention as they once were. Enforcement of the hazard reduction requirements of the Bush Fires Act has become lax in some cases, so that some rural towns are now in an extremely hazardous situation, with high levels of forest fuel in their vicinity.
Bushfire Damage
In severe fire seasons the damage caused by bushfires is astronomical. In the 2002 Canberra fire disaster, for example, the cost to insurers alone was $257 million (The West Australian, 13 Feb, 2003). The total cost of the fires, including the cost of suppression measures and lost productivity, would be much greater than this figure. Add to it the loss of life, personal trauma, loss of invaluable personal possessions and destruction of scientific equipment and data from the Mt Stromlo Observatory, and the ramifications of such disasters start to become apparent. And it does not end with the direct impacts of the fire. We all lose financially because the inevitable consequence of any large disaster is a rise in insurance premiums.
Results of the Canberra fire 2003
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How much better then, if we can avoid, or at least minimise the risk, of such disasters happening again. While the Canberra fire disaster was a complex issue, with several factors contributing to the outcome, experienced fire managers have estimated that a prescribed burn costing about $100,000 would have prevented the disaster, but the burn did not take place due to mistaken land management policies. A mere $100,000 set against well over $257 million would seem a good deal for the community.Canberra is not the only city to have suffered from bushfire damage in recent years. Sydney has experienced a series of lesser, but still serious, bushfire disasters since 1994. In some respects most Australian city fringes and country towns have become more prone to bushfire damage over the past 30 or so years, with the proliferation of rural lifestyle smallholdings and natural vegetation reserves that are preserved, rather than actively managed. Many people who move into rural smallholdings have little awareness of fire management issues.
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| Jarrah forest defoliated by wildfire | ||
Public infrastructure also suffers in major wildfires, Bridges may be burnt, powerlines damaged and industrial plants destroyed. All these lead to diversion of Government resources to repair them, or to reduced economic performance by industry. Apart from the inconvenience of interrupted access, lack of electrical power and economic activity, job losses are frequently added to human woes. Of course, the forests incinerated by these intense bushfires also suffer great damage. Unlike the usual description employed in the media, most native forests are not “destroyed” by wildfire. Some are. Ash-type eucalypt forests are killed in this way, as the 1939 Victorian fire disaster clearly demonstrated.
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| Severely fire-damaged jarrah forest | ||
Drier forest types, such as jarrah in WA are not destroyed, although some individual trees may die, the forest cover is not removed. Most eucalypts have a number of specialised features that enable recovery from intense fires. The remaining trees are, however, damaged in a number of ways. The cambium (the growth layer under the bark) may be killed in one side of the bole, resulting in “dry sides” which are subsequently prone to insect attack, degrading the timber for almost any use. Rots also gain entry via dry sides and burnt limbs. Trees that already have “hollow butts” will often burn out completely and fall, and new hollow butts will be created when a dry log burns alongside a standing tree. The upper parts of saplings and small trees are often killed so that the stems become malformed, thus reducing their potential commercial value, as well as permitting access by damaging fungi and insects. Intense bushfires cause the death, by incineration or smoke suffocation, of large numbers of native animals and insects that are unable to avoid the flames. Microsites that do not burn under low intensity burns are incinerated and there are thus no refugial areas left for fire sensitive flora or fauna, or for subsequent recolonisation after the fire.
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| Quokka overcome by a wildfire | ||
The large areal extent of severe wildfires means that, unlike prescribed burning where any fauna losses are quickly made up from surrounding unburnt forest, there are wholesale fauna losses. The potential for total loss of a rare and endangered species is clear. In the case of pine plantations, on which we are now so dependent for timber supplies, the trees are killed by high intensity fires. The logs may also be degraded for certain end uses by charcoal. Destruction of immature plantations disrupts the flow of future timber supplies, with adverse impacts on local employment. In blue gum plantations, we can expect that high intensity fires will kill most trees and, due to their small size, the degradation of logs by charcoal will render them useless for pulpwood, their intended market. 
Bushfires also generate smoke, massive amounts of smoke, and much more per unit area than a prescribed burn, because there is much more complete combustion. Such huge volumes of smoke can dislocate aerial communications and affect human health, as we have seen in South East Asia in recent years.
Bush Fires and Water Supplies
High intensity wildfires have very adverse effects on water supply catchments. The immediate impact is a great increase in runoff from the next rainy period, due to the lack of interception by tree and understorey foliage. While this may appear to be a benefit for dam storage, in fact it is not, as it is accompanied by extensive soil erosion and the transport of large quantities of silt and ash into the water storage facility. The ash is highly detrimental to water quality and can actually cause a dam to be withdrawn from the supply system. This happened in Canberra after the 2003 fire disaster there. The silt and ash flow can also damage or even destroy valuable stream gauging stations (see the paper presented by Colin Terry at the Eaton Seminar in the References section)
In the large Perth Hills bush fire of 2005, monitoring of a Water Corporation experimental catchment showed that water yield increased by a factor of 2.2 times in the first year, but then returned to normal afterward, However, over 350 cubic metres of soil were deposited in the stream bed, silting up the stream and small pools. Large amounts of silt and ash passed through into the Mundaring Weir. A survey by the Department of Environment and Conservation found that aquatic diversity was significantly impaired in the wild fire area. Invertebrates in the wildfire area were also much less diverse than those from areas that had been prescribed burned. It was estimated that between 1.5 and 2.3 million trees were killed outright by this high intensity fire. The forest has therefore been significantly degraded by this one wild fire. It will take many, many years to replace these trees.
Analysis by the Water Corporation of prescribed burn data and water flow over a 40 year period (1960-1999) showed a stream flow increase of between 20-49% for two years after each burn, As most burning is carried out in spring, when the stream zone is moist, there is minimal damage to vegetation and water quality. On the Gnangara Mound, recharge to the water table increased for 5 years after a prescribed burn.
In view of the great importance of the forested catchments in the Darling Range and the Gnangara Mound to metropolitan water supplies, it is imperative that high intensity wildfires be excluded from the region. It is so important that this happen that the management priority for the region should be reviewed and catchment protection be given higher priority than the current DEC top priority for biodiversity protection. The entire area covered by the harnessed catchments or groundwater areas needs to be managed on a 5-7 year prescribed burning rotation.