A wildfire, also known
as a forest fire, vegetation fire, grass fire, or bushfire (in
Australasia), is an uncontrolled fire in wildland often caused
by lightning; other common causes are human carelessness and arson.
Drought and the prevention of small forest fires are major contributors
to extreme forest fires. The word "wildfire" originally
meant a medieval European weapon substance somewhat like napalm;
the word got its present meaning by people misunderstanding the
expression "spread like wildfire". Wildfires are common
in many places around the world, including much of the vegetated
areas of Australia, forest areas of the United States and Canada,
where the climates are sufficiently moist to allow the growth
of trees, but feature extended dry, hot periods when fallen branches,
leaves, and other material can dry out and becomes highly flammable.
Wildfires are also common in grasslands and scrublands. Wildfires
tend to be most common and severe during years of drought and
occur on days of strong winds. With extensive urbanization of
wildlands, these fires often involve destruction of suburban homes
located in the wildland urban intermix.
Today it is accepted
that wildfires are a natural part of the ecosystem of wildlands,
where, at the least, plants have evolved to survive fires by a
variety of strategies (from possessing reserve shoots that sprout
after a fire, to fire-resistant seeds), or even encourage fire
(for example eucalypts contain flammable oils in the leaves) as
a way to eliminate competition from less fire-tolerant species.
In 2004, researchers discovered that exposure to smoke from burning
plants actually promotes germination in other types of plants
by inducing the production of the chemical butenolide. Most native
animals, too, are adept at surviving wildfires. On occasions,
wildfires have caused large-scale damage to private property,
particularly when they have reached urban-fringe communities,
destroying many homes and causing deaths.
Above Images Are From The U.S.D.A.