Fire ecology is the study of wildland fire and its relationship to the environment. Key factors in fire ecology include fire dependence, where some plant species rely on fire for regeneration; fire history, which can be determined by studying tree ring records of past fires; and fire regimes, which describe the patterns of fire frequency, intensity and fuel consumption over long periods. Fires are caused both by human activities and lightning, and can have various effects on both abiotic and biotic factors in an ecosystem. Many plant and animal species have adaptations to either tolerate, resist or depend on fire. Different types of fire spreads including surface fires, crown fires and ground fires. While high intensity fires can cause damage, fire also provides key ecological benefits such

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Ecological factor
• An interesting ecololgical factor
It is a part of natural world just like wind,rain
etc.

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Fire ecology
It is a branch of
ecology that focuses
on origins of
wildland fire and its
relationship to
environment that
surrounds it both
living and non living.

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Factors of fire ecology
• Fire dependence
• Fire history
• Fire regime
• Causes
• Effects
• Fire spread and its types

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1;Fire dependence
• In 1930s researchers in
southern united states
argued against negative
perspective of fire with
belief that fire is bad.
• They recognized that
some species of plants
rely upon the effects of
fire to make the
environment more
hospitable for
regeneration and growth.

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2;Fire history
• It deals with how often fires have occured
in a given geographical area.
• Trees are our source of information on
fires in the distant past.

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a] Fire scars
• Trees record their history
through a system of
growth rings that develop
on the trees each year.
When a fire goes through
an area, the growth rings
of that particular tree may
be scarred. On live trees
this is called a fire scar.
• Fire scars can also be
seen on dead trees
• Fire Scars and Tree Rings
• Cross-section of a tree
showing fire scars

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Fire-scarred oak

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b] Dendrochronology
• The study of growth rings is called
dendrochronology.
• Utilizing dendrochronology, we can
determine when fires have occurred in the
past, and sometimes determine their
intensity and direction as well as other
information about the weather patterns in
that era.

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3;Fire regime
• Fire regime refers to the patterns of fire that occur over long
periods of time, and the immediate effects of fire in the
ecosystem in which it occurs.
• It is a function of the frequency of fire occurrence, fire
intensity and the amount of fuel consumed.

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4;Causes of fire
Approximately 90% of fires in the last
decade have been human-caused, either
through negligence, accident.
The remaining 10% of fires are caused by
lightning strikes,

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5;Effects of fire
Abiotic responses
1] Fire can affect the soil by direct contact with it
and by its effects on the plant community
associated with it.
By removing overhead vegetation, fire can lead to
increased solar radiation on the soil surface by
day, resulting in greater warming, and to greater
cooling through the loss of radiative heat at night.

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2 Fewer leaves left to intercept rain will allow
more moisture to reach the soil surface.
3 In addition, plant transpiration will be reduced
following a fire, allowing the soil to retain more
moisture.
4 Exposure to sunlight, wind and evaporation,
however, will work in the other way, to dry the
soil.

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Radiata Pine forest burnt during the
2003 Bogong Bushfires, Australia

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Biotic responses
• a] Plants
Plants have evolved many adaptations to
cope with fire.
• pyriscence,
• serotiny,

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• Maturation and release of seeds is triggered, in
whole or in part, by fire or smoke; this behaviour
is often erroneously called serotiny.
• On the other hand, germination of seed
activated by trigger is not to be confused with
pyriscence; it is known as physiological
dormancy.

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• A lodgepole pine
forest is naturally
adapted to fires. The
pines' serotinous
cones have a waxy
coating which opens
in response to the
heat of the blaze,
scattering seeds on
soil.

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The cones of the Lodgepole pine (Pinus contorta) are, conversely,
pyriscent: they are sealed with a resin that a fire melts away, releasing
the seeds.

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• Many plant species, including the shade-
intolerant giant sequoia (Sequoiadendron
giganteum), require fire to make gaps in
the vegetation canopy that will let in light,
allowing their seedlings to compete with
the more shade-tolerant seedlings of other
species, and so establish themselves.

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Gaint sequoia plants

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• some plants have leaves coated in
flammable oils that encourage an intense
fire. This heat causes their fire-activated
seeds to germinate,

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b] Fire intolerance
• Fire-intolerant plant species tend to be
highly flammable and are destroyed
completely by fire.

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“Obligate seeders
They are plants with large, fire-activated
seed banks that germinate, grow, and
mature rapidly following a fire, in order to
reproduce and renew the seed bank
before the next fire.Seeds may contain the
receptor protein KAI2, that is activated by
the growth hormones karrikin released by
the fire.

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Banksia cone opened by the fire to release seeds
(serotiny)

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c] Fire tolerence
• Fire-tolerant species
are able to withstand
a degree of burning
and continue growing
despite damage from
fire. These plants are
sometimes referred to
as “resprouters”.
Typical regrowth after an
Australian bushfire

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d] Fire resistance
• Fire-resistant plants suffer little damage
during a characteristic fire regime. These
include large trees whose flammable parts
are high above surface fires

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Birds,animals and microbes
• Birds are vulnerable when
nesting, they are generally
able to escape a fire;
• Mammals are often capable of
fleeing a fire, or seeking cover
if they can burrow.
• Amphibians and reptiles may
avoid flames by burrowing into
the ground or using the
burrows of other animals.
Amphibians in particular are
able to take refuge in water or
very wet mud.
A mixed flock of hawks hunting in and
around a
bushfire

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• Microbial organisms in the soil vary in their
heat tolerance but are more likely to be
able to survive a fire the deeper they are
in the soil.
• An increase in available nutrients after the
fire has passed may result in larger
microbial communities than before the fire.

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Fire spread and its types
• a;Ground fires—which burn organic matter
in the soil beneath surface litter and are
sustained by glowing combustion.

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Creeping ground fire at Grand Canyon National
Park, Arizona

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b;Surface fires
• Which spread with
a flaming front and
burn leaf litter,
fallen branches
and other fuels
located at ground
level.
Surface fire at Grand Canyon National Park,
Arizona

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c;Crown fires
• Which burn through
the top layer of foliage
on a tree, known as
the canopy or crown
fires. Crown fires, the
most intense type of
fire and often the
most difficult to
contain, need strong
winds, steep slopes
and a heavy fuel load
to continue burning.
Crown fire at Yellowstone National Park,
Wyoming

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Size and intensity
• In the United States, 2 to 3 percent of all fires account for
more than 95 percent of the total area burned annually.
The blackened plots left behind by these types of large
fires contribute to the image of fire as a destroyer of the
natural environment.
• High intensity fires can cause as soil destruction, such as
loss of nutrients and removal of debris needed to protect
seedlings.
• In areas where such damage occurs, rehabilitation plans
are made and actions are taken to reduce further
damage and to try to restore the area.

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Benefits of Fire
• Insect pest control
• Removal of exotic, or non-native, species that
compete with native species for nutrients and
other needs
• Addition of nutrients for trees and other
vegetation provided by ashes that remain after a
fire
• Removal of undergrowth, thereby allowing
sunlight to reach the forest floor to encourage
growth of native species
• Encourage the growth of fire-dependent species

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After a Fire
• Furthermore, a burned
tree is not wasted. It can
provide nesting sites for
birds, homes for small
mammals and a base
from which new plants
can grow.
• When the dead tree
begins to decay, it
releases nutrients into the
soil, enhancing growth of
surrounding flora.

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Disadvantages
• Fire can cause soil damage, especially through
combustion in the litter layer and organic material in the
soil. This organic material helps to protect the soil from
erosion.
• When organic material is removed by an essentially
intense fire, erosion can occur.
• Heat from intense fires can also cause soil particles to
become hydrophobic.
• Rainwater then tends to run off the soil rather than to
infiltrate through the soul. This can also contribute to
erosion.

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ANY QUESTION?