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Forest fires or wildfires
are defined as the uncontrolled burring of wooded lands. It may last within
several minutes or may even continue for few months. Single event of forest
fire can wipe out the whole ecosystem within a few minutes.
Three basic requirements
such as heat, oxygen and a source of fuel should be fulfilled in order to
generate a forest fire. Generally, decaying materials like fallen branches and
leaves in the forest floor provide the fuel for the emerging fire. Lighting
supplies the heat for the burning forest biomass. Heat is required for the fuel
to reach its ignition point. The prevailing windy conditions can increase the
availability of oxygen over the forests.
There are two types of
forest fires.
Natural forest fires
The forest fire is a
natural phenomenon in the temperate forests during the summer. It helps to
regenerate the vegetation time to time. It does not act as a massive event and
only burn out small portion of the forests.
But, high temperature
result of the global warming and climate change has intensified this natural
phenomena and which does not last even after a few days and spread and damage a
large patch of forests.
Long lasting droughts due
to the climate change also increases frequency and intensity of natural wild
fire and spread into a larger area and make them are unable to control even by
the fire fighters.
Man induced forest fires
Forest fire are not
naturally occurred in the forests in the topical regions. Here, man induced
forest fires are becoming so common due to the regular human activities.
People’s careless actions
like throwing away the last portion of cigarette have ability create a large
prevalent fire in forests during droughts.
Intentional human
activities like intensified slash and burn agriculture and setting fires to
catch wild animals leads to development of uncontrolled fires in the forests.
Under the rehabilitation
programs of damaged forests or the establishment of the commercial forest
plantation, nations in tropical regions have decided to grow the fire prone
forest plant species like Acacia species which are native to temperate
region. Generally, leaves of this types of forest trees have low amount of
moisture content. Furthermore, leaves of such trees make a non-decayed mat in
the forest floor and provides the fuel for the burning. Thereby, these trees
produce ideal conditions for the regular events of forest fire in their
inhabitant ecosystems.
Long lasting droughts due
to the climate change also increases frequency and intensity of natural wild
fire and spread into a larger area and make them are unable to control even by
the fire fighters.
Effects of forest fires
Even though occasional
natural fire events may help to regenerate the ecosystem, the massive fire
hazard cause severe damage to the forest ecosystem. Even one adverse fire event
is enough to disappear the whole ecosystem and convert the previous forest
ecosystem into a desert.
1) Loss of carbon storage
The forests play an
important role in the storing the atmospheric carbon that release from both anthropogenic
and natural activities. The loss of carbon dioxide from the sinks in the forest
is very low compare to other sinks unless there is a disturbance event.
Generally, two types of
carbon pools are found in the forests.
Soil and dead trees acts
as the non-living carbon pools while living trees and shrubs in the under-story
layers functions as the living pools in the forests. Forest soil is considered
as the largest carbon pool in the terrestrial environment.
So, a disturbance event
like wild fire can vanish these carbon pools and release a large amount of
sequestered carbon dioxide within a little time. Usually, the complete when
only there is enough amount of oxygen, organic materials are burnt completely
and result in carbon dioxide. But with time, the continuous supply of oxygen decrease
to burning of forests. So, incomplete burning of forest materials leads to the
production of toxic gases like carbon monoxide (CO), methane (CH₄) and nitrogen
oxides (NOᵪ). In addition to these two gases, excess amount of particle
matters, sulfur dioxide also release from this event.
Emission of the toxic
gases cause the health problems in wild animals as well as in surrounding
people. The sudden release of excusive amount of particles matters produces
photochemical smog onsite which turn in result reduction of the visibility and
significant temperature reduction in remote areas.
2) Extinction of flora
and fauna
One catastrophic event is
capable of destroying the entire population of point endemic fauna and flora
and cause the extinction of such species. Generally, endemic species are
fragile and highly adopted to their local environment. So, a massive
disturbance event like forest fires can wipe out them from the entire planet.
3) Invasion of the
disturbed wooden land by invasive plants and animals
Disturbance to natural
ecosystem make them more vulnerable for the growth of invasive plants and
animals. Infertile soil, high amount of sunlight and zero shade may create ideal
conditions for the invasive plants. The development of invasive vegetation
retreads the growth of emerging seedling of natural vegetation from the
underneath seed bank. And they also make the environment unfavorable for the
regrowth of previous vegetation by decreasing the availability of nutrients and
water and killing beneficial microorganisms in the soils.
4) Soil erosion
Forest fire remove the
surface cover of the forest soils. Roots of the trees and shrubs and natural
mulch including decaying plant materials protects the soil against the erosion
by avoiding the direct contact of rain droplets with the soil. However, a rain
receive after a massive wild fire results in soil erosion in the degraded
ecosystem. The rain droplets fall directly into forest soil and cause the
dislodging and washing away of large amount of soil particles into nearby water
streams. This process interferes with aquatic through the sedimentation and
water pollution.
Prevention of forest
fires
Awareness Programmed
should conducted to people inhabiting around forests ecosystems and tourists to
transfer the knowledge on the importance of forest ecosystems, and prevention
and control of forest fires.
Buffer zones with fire
resistant plant should be established around the forests. Forest plants species
with higher amount of moisture content or muscular leaves and low amount of
volatile compounds are able to discourage the spread of fire beyond them. But,
even this type of plants are useless when the fire continuous for hours and
cause them to loss their moisture.
It is important to avoid
the planting fire prone forest plant species in the degraded forest ecosystems.
So, natural plant species of the ecosystems should be replanted despite of
their slow growth rates under the reforestation programs.
Existing laws regarding
the wild fauna and flora should be strengthen or new laws should be enforced to
punish the people setting fires in the wooded areas.
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