FoReSt FiReS.(:


What Are They?


Forest fires, or wildfires, are a natural occurrence that are often used to signify an
uncontrolled or intense fire that breaks out in wooded areas due to many man made
causes. They may have many benefits, as well as many disadvantages. Forest fires
generally occur during days with strong winds and on years of drought.
forest_fire_causes.gif



What Are the Causes?


Forest fires are often cause by lightning strikes, volcanic activity, human carelessness,
underground coal fires, and slash-and-burn farming. Since
lightning strikes are often associated with rain, the wildfire generally
gets put out by the rain. Pyroclastic clouds, generated from active
volcanoes, are one of the main causes of forest fires. Human
carelessness generally involves people using fireworks and the fireworks
catch a tree on fire, then it goes from there. Underground coal fires cause wildfires
due to the burning of slow and flameless forms of combustion below Earth's surface.



Benefits of Forest Fires

Without forest fires, the build up of vegetation in a forest may prevent certain seeds
from germinating and prevent the growth of new trees. Forests that do not have a
regular occurrence of a fire have no way of destroying some of the thick vegetation
that that grows, therefore causing a major problem. The forest grows extremely
dense and becomes
smokey_the_bear.gif a massive source of fuel for future fires, making fires that
will burn much hotter and more destructive to the environment. Yet, but not least,
forest fires open the forest floor which allows sunlight in for more growth of different
species, and the ash left behind puts plenty of nutrients into the soil.



Disadvantages of Forest Fires

There are many disadvantages of forest fires also. Forest fires are the loss of habitats for
many well known species. Occasionally, the fires may cause soil damage which may result in
erosion. That is very rare to occur though. Forest fires generally result in uncontrolled
burns, which results in millions of dollars worth of all the homes and property that is
destroyed. Sometimes, forest fires have the potential to cause human deaths and serious
injuries.



Fire Safety

There are many precautions you should take while
experiencing a forest fire. Fires are very
unpredictable,
so ALWAYS be prepared. Fires can also get out of
control very easily,and can burn for a long period of
time. In time of which a fire may occur, always evacuate
your home if told to do so. This one simple precaution
may just save your life. Learn and teach safe fire
practices to insure completely safety. Use fire-resistant
materials when building, renovating, or retrofitting a
structure. Create a safety zone to separate your home from
combustible plants and vegetation that would most likely
cause your home to catch on fire. Every so often, make
sure to check for fire hazards in or around your home.
You never know what may be hiding!



Where do they occur?

Forest fires occur on all continents except Antarctica. They are wildfire.jpg
most common where climates are wet enough to allow trees and shrubs
to grow, but have extended dry, hot periods. The most
noted areas of these forest fires would include the Western
Cape of South Africa, vegetated areas of Australia, and all throughout
grasslands and the dry forests of Europe and North America.

Western U.S. fires tend to be the most dramatic during fall
and summer. Southern fires are hardest to fight in early spring
and late winter due to the fallen branches, leaves, and other materials
that dry out and become highly flammable. Forest fires that occur in
forests and grasslands in North America are prevalent in the fall and
winter, summer, especially during dry periods with an increase in high winds
and dead fuels.



Fire Ecology

Forest fires effect the surrounding land and ecosystems around it. Many animals lose
their habitats to the fires, or perish. Many species have become adapted to these ecosystems
though. They are called fire tolerant plants. Fire tolerant species are able to withstand some
forms of fire and grow despite some damage that may occur during the fire. Some people refer
to these plants as "resprouters." Ecologists have shown that some species of "resprouters"
may store extra energy in their roots for recovery and for the re-growth of that speciesforest_fire.jpg
following a fire. This will help them grow back more quickly and easily.

Fire intolerant species tend to be extremely flammable and will be completely destroyed by a
forest fire. They have no chance of being able to withstand a fire. In time, some of these
plants and their seeds may slowly fade from the ecosystem after a fire, or multiple fires, and
may never return to that same ecosystem again. Therefore, making them become endangered.
The most common types of fire intolerant species are the White pine, American beech, red maple,
red and white oak, and aspen.




How do the fires spread?

Fires spread at many different rates, depending on the wind and the slope of the terrain, which
would be the topography of the land. Fires may burn at up to three different levels. They are
ground fires, surface fires, and crown fires. Ground fires, which burn on the ground or below
the vegetation under the ground, are often best controlled by digging trenches. These trenches or
"firelines" are dug deep down into the mineral soil layer, which has no way of burning. Eventually,
the fire reaches one of these "firelines" and it can no longer burn due to the minerals in the soil.
The fire then extinguishes itself because it is starved of fuel. Ground fires are very difficult to
detect and control. Most of the time, they often rekindle.

Surface fires may even burn through dead plant material that is on the ground. They tend to move more
quicker, requiring more manpower and equipment. Portable backpacks, along with packs and fire breaks
are used to put out these surface fires out. Those methods require a lot of labor though and are very
straining on a person.

Crown fires are the most the most dangerous way a fire may burn and they tend to spread the fastest.
These fires occur in the tops of trees where it is very easily for them to spread because they can literally
"jump" from crown to crown. Occasionally, when there are harsh wind conditions, crown fires have been
known to even cross rivers and even lakes. Due to the intensity of these fires, aerial bombing with water
and/or fire retardant chemicals are called in to put out these dangerous fires.





Sources


http://outside-blog.away.com/blog/2009/12/smokey-got-it-wrong.html



http://library.thinkquest.org/C003603/english/forestfires/index.shtml



http://en.wikipedia.org/wiki/Wildfire


http://forestry.about.com/b/2010/03/02/forest-fire-basics-and-the-behavior-of-forest-fires.htm


http://www.borealforest.org/world/innova/fire_suppression.htm