What is a
A bushfire is
a more general term than forest fire for the typical kind of wildfire
that occurs in Australia. A bush is a collective term for scrub,
woodland and grassland in Australia, New Zealand and New Caledonia.
Consequently they do not only occur in wooded areas, but also (and very
frequently) in the large Australian grasslands.
processes are often the driving factor behind bushfires.
They occur in several parts of the continent, depending on the season.
summer and autumn bushfires are most common and most severe in
Southeast Australia – and then mainly in drought years, and
particularly severe in El Niņo years. Subsequently south east Australia
is considered one of the most fire prone areas of the world.
the southwest too bushfires occur in the summer dry season, but here
severity is usually related to seasonal growth.
During winter and spring bushfires usually occur in the north of
Australia (where winter is the local dry season), and fire severity
tends to be mainly associated with seasonal weather patterns.
bushfires are strongly influenced by natural circumstances (lightning,
volcanic eruptions, vegetation structure, climactic factors such as
temperature and rainfall, topographical factors such as elevation and
slope), many of them are nevertheless man-induced.
been a part of Australia’s nature for millions of years. The natural
fire regime was profoundly altered by the arrival of humans in
Australia. It is assumed that a good deal of this change came about as
the result of deliberate action by early humans, setting fires to clear
undergrowth or drive game. This pattern was even worsened with the
arrival of the first European settlers in the 18th century.
distribution from April 1998 to March 1999 (left) and from April 1999
to March 2000 (right) as mapped from NOAA-AVHRR imagery - Source
Today it seems the human impact on bushfires is ever increasing. No
longer just because of the direct effect on vegetation, habitation and
other fueling infrastructure, nor just because many of the fires are
man-induced (be it deliberately or accidentally), but also because of
the global effect humans appear to have on the warming climate. Global
warming affects many climate systems all over the world,
and would also be responsible for the ever increasing
drought in Australia, which induce more
frequent and more severe bushfires.
|Fires detected by MODIS over a 10-day
period for each image (left: summer and right: winter):
30/05/2000-08/06/2000 - 31/01/2001-09/02/2001 30/05/2008-08/06/2008 -
31/01/2009-09/02/2009 - Source: NASA
effects on nature as well as on humans. In nature most species are
severely affected by fire. Most fauna and flora is instantly killed
during a bushfire, but there are some species that manage to profit
from – or at least survive – a bushfire: some plant species such as
Eucalyptus even developed a lignotuber, a starchy swelling of the root
crown as a protection against destruction of the plant stem by fire.
Others, such as the Swamp Paperbark (Mullica rhaphiophylla) have the
capacity to sprout new growth from groups of little buds under the
bark. The dormancy of these buds is only broken by the heat of fire.
These processes are the result of
millions of years of evolution, but as soon as man landed on the shores
of the continent, fire regimes were altered. The resulting habitat changes have been
widespread. Where fires became more frequent, for example,
fire-resisting species - notably eucalypts - greatly expanded their
In addition to
their impact on the environment, bushfires nowadays have a severe
impact on life, health (through reducing
air quality), property, infrastructure
and primary production systems.
Over the past 40 years, fires have claimed more than 430 lives, making
them the most hazardous form of natural event in
mass burnt across Australia in bushfires, forest fires and
agricultural fires between 1983 and 1998 - Source
Their financial cost, around AU$2.5 billion over the same period,
represents about ten per cent of the total costs of natural disasters
majority of the impacts on life, property and infrastructure occur in
southern Australia, where human settlement is greatest and where
extreme fire weather conditions occur in most summers.
example: Black Saturday
bushfire ever recorded was the huge bushfire earlier this year, called
the Black Saturday bushfires since they
started in Victoria on and around Saturday 7 February 2009.
weather conditions were extremely suitable for bushfires, resulting in
Australia's highest ever loss of life from a bushfire: no less than 173
people died in the fires and about 500 were injured. The fires
destroyed at least 2,000 homes and damaged thousands more. Many towns
north-east of the state capital Melbourne were badly damaged or almost
completely destroyed. In total, the Black Saturday bushfires affected
78 individual townships and left an estimated 7,500 people homeless.
main causes of the fires were fallen or clashing power
lines and arson. Other suspected ignition sources
include lightning, cigarette butts and sparks from a power tool. More
distantly implicated was a major drought
that has persisted for more than a decade, as well as a domestic
50-year warming trend that has been
linked to human-induced climate change. By early-mid March, favourable
conditions aided containment efforts and extinguished the fires.
Several measures can
be taken when fighting the often devastating effects of bushfires.
- Since arson appears
to be quite a common trigger of bushfires, Australia invests largely in
arson-reduction programs, mainly focusing on school and community.
- Land use planning,
development controls and building standards have a central role in
reducing the risk to people and property from bushfire as well.
- Modification of
elements of the landscape is a third important means of reducing risks
to assets. Among the objectives of landscape modification are reducing
the probability of a bushfire starting, slowing its spread, limiting
its intensity so that it might be controlled, and maintaining
ecological processes and biodiversity.
- Creating a mosaic
of fire regimes across a landscape – with fire intervals, seasons and
intensities in the mosaic appropriate for particular ecosystems –
appears to be the best means of sustaining biodiversity and should be a
goal of both ecological and fuel-reduction burning.
But apart from
preventive measurements, Australia is also trying to be ready whenever
a fire does occur. Readiness is important for both individuals and land
management agencies. An incident management team needs to be ready to
provide comprehensive operational information. The media have a
particularly important role to play in conveying accurate and timely
implementation of these two branches of bush fire policy – prevention
and response – influence greatly the severity of the fires.
Fires have a
fundamental and irreplaceable role in sustaining many of Australia’s
natural ecosystems and ecological processes, and they are a valuable
tool for achieving many land management objectives. However, if they
are too frequent or too infrequent, too severe or too mild, or
mistimed, they can erode ecosystem ‘health’ and biodiversity and
compromise other land management goals—just as uncontrolled fires can
threaten life, property, infrastructure, and production systems. It is
an ongoing and increasing challenge for the people of Australia to keep
fighting fires in a changing world.
Australia Bushfire Monitor
Australia: Victoria bushfires - The
International Federation of Red Cross and Red Crescent Societies
Bush Fires in South Australia - Global Fire
Monitoring Center (GFMC)
Living in a land of fire - Australian
People and bushfires : factors affecting
fire frequency - Australian Government
Report of the National Inquiry on Bushfire
Mitigation and Management - Australian Government
Wikipedia Bushfire - Bushfires in Australia
Earth from Space:
‘Black Saturday’ bushfires - ESA Observing the Earth