Fire

Introduction
 Fire is an important ecological factor and fire ecology is concerned with natural
processes involving fire in an ecosystem along with its impact on the ecosystems.
 Many ecosystems like prairie, Savanna, Chaparral and Coniferous forests have evolved
with fire as an important contributor to habitat.
 Many of the plant species require fire to germinate , establish or to reproduce .
 Suppression of wild fire indirectly effects the growth and survival of the different species.
 Fire is an integral component of the function and biodiversity of the many natural
habitats.
 Fire is now thought to be as natural disturbances along with flooding, wind storms,
landslides that has driven the outcome of the different species in the passage of the
biological evolution. Frequency, intensity and area associated with fire are some
important in this regard

FIRE REGIME
 Fire regime refers to the characteristics of natural fire and how it interacts
with particular ecosystem.It is classified as per frequency, intensity, size,
pattern, season and severity.
 Three levels of fire are found-
I. Ground fires:- burn the rich organic matter
II. Surface fires:- burn dead plant materials,
III. Crown fires :-that burns the tops of shrubs & trees.
IV. Wild fires :- generally occur during the time of lightning.
 There are four fire components-fuel, heat, oxygen and a sustained chemical
reaction. It is called fire tetrahedron.
 First three components are called fire triangle .
 The energy released per unit length of fire line is KW /m.
 Whatever may be, the fire has strong effect upon the vegetation as stated
below

Fire and plants
 Fire, being an abiotic components has strong effect upon
the other non-living components of an ecosystem in general
and soil in particular.
 Fire can remove vegetation that leads to increased solar
radiation on the soil surface resulting greater warming and
faster cooling of the surface.
 Fewer leaves left to intercept rain to allow more moisture
retention in the soil surface.
 Fire changes the status of the soil nutrients including
oxidation, volatilization , erosion and leaching,
 Plant decaying mineral nutrients are more soluble and
available in the form of ash and promotes the erosion of
surface nutrients.
 Soil becomes more basic in pH and alter the clay content
and porosity of the soil.

ADAPTATIONS OF PLANTS ON FIRE
 Despite fire,plants can adapt itself by a good number of
adaptibility.Plant species can be:-
1. Fire intolerant:- Species are highly flammable and completely
destroyed by fire. However, some of these plants seeds may
germinate and grow after the fire.
2. Fire tolerant:- The plant species can withstand fire up to
certain degree and continue growing. These plant species are
referred as resprouters that store extra food in their roots. This
provides energy for recovery and regrowth after fire.
3. Fire Resistant:- These type of plants suffer little damage during
characteristic fire regime. These includes large trees whose
flammable parts are high above the surface fires. Pine ponderosa
is an example of a tree species that suffers virtually no crown
damage under the naturally mild fire regime.

EFFECTS OF FIRE
 In addition to the direct killing effects on plants, fir has lot of effects in the following
ways.
 Some trees as a result of fire have large scars on their stems. This scars enables a safe
passage of the entry of pathogens inside the plants for causing diseases.
 Fire brings a marked alteration of different factors like rainfall, nutrient recycling,
fertility of soil, and other indispensible factors of the surroundings. Such alteration
even may cause long term damages of the surroundings.
 Fire tolerant species increase in abundance killing fire sensitive species and this
ultimately cause gene erosion.
 Fire has some positive roles. Cynodon sp, Paspalum sp like herbs are stimulated by
fore to produce large quantities seeds .

ADAPTATIONS OF PLANTS ON FIRE
 Plants have evolved different types of adaptations to cope up with fire.
 Pyriscence is a part where maturation and release of seeds is triggered in a whole or in
a part by fire or smoke.This behavior is called serotiny.
 All pyriscent plants are serotinous but all serotinous plants are not pyriscent.
 Some plants are smoke-0 activated seeds or fire-activated buds.
 The cones of Pinus contorta are pyriscent. They are sealed with resins.The fire melts
away, releasing seeds. Many plant species including giant sequuoia ( Sequoiadendron
gigantum) require fire to make the gap in the vegetation canopy that will left in light,
allowing their seedlings to compete with more shade tolerant seedlings of other
species and to establish themselves.
 Thus, plants enable to compete with fire for their survival.

CONCLUSION
 The environment is a complex of so many things like light, temperature, wind, fire etc
and these factors play a very crucial role in the dynamic nature of a sustainable
ecosystem.
 Any external factors of the discussed above affects the life of the organism in any way.
The sum of all these ecological factors either living or non-living makes the
environment of an organism.
 The habitat indeed presents a particular set of conditions called environmental
complex .
 The understanding of the different factors and their role is very significant one in
order to understand the ecology as a whole and the individual in particular.

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