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FOREST FIRE

Dr. M Nazish Khan

IDRS & GIS Apps., AMU

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INTRODUCTION

Forest fires are major disasters that destroy many forest resources and damage the ecological environment.

For millenniums, Forest and wildland fires have been taking place and shaping landscape structures, patterns and even the species composition of ecosystems.

These fires are considered important for natural ecological

processes initiating natural exercises of vegetation succession.

However, artificially planting these fires and the misuse of it can cause tremendous adverse effects on the ecosystem and human society.

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INTRODUCTION

• Wildfires present a challenge for ecosystem

management, because they have the potential to be at once beneficial and harmful.

• On the one hand, wildfires are a natural part of several ecosystems for maintaining their health and diversity in numerous ways, such as regulating plant succession and fuel accumulations, controlling age, structure and

species composition of vegetation, aecting insect and disease populations, influencing nutrient cycles and energy flows, regulating biotic productivity, diversity and stability and determining habitats for wildlife.

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INTRODUCTION

On the other hand, wildfires can also become a threat to

property, human life and economy, particularly in ecosystems where fires are an uncommon or even unnatural process.

Despite the prominence of fire events, current estimates of the extent and impact of vegetation fires globally are still a challenge.

Several hundred million hectares of forest and other

vegetation types are estimated to burn annually throughout the world, consuming several billion tons of dry matter and releasing emission compounds that aect the composition and functioning of the global atmosphere and human health.

According to the FAO (FAO 2012), wildfires are important climate forcing factors as they release aerosol between 25- 35% of the total CO2 net emissions to the atmosphere.

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Causes of Forest Fire

• Natural Causes:

• Anthropogenic Causes:

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Natural Causes

• Lightening: Generally, forest fire is started by the sudden fall of lighting on the dry forest or old trees or grasses.

• Combustion: sometimes, fire may be ignite

due to sudden combustion of sawdust and dry

leaves during hot summer.

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Anthropogenic Causes

• Agriculture operations

• Transportation and communication

• Logging and forestry operations\

• General public mistakes

• Arson

• Other causes

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Types of Forest Fire

Surface Fire: A forest fire may burn primarily as a surface fire, spreading along the ground as the surface litter (senescent leaves and twigs and dry grasses etc) on the forest floor and is engulfed by the spreading flames.

Underground Fire: The fires of low intensity, consuming the organic matter beneath and the surface litter of forest floor are sub-grouped as underground fire.

Ground Fire: These fires are fires in the sub surface organic fuels, such as duff layers under forest stands, Arctic tundra or taiga, and organic soils of swamps or bogs.

Crown Fire: A crown fire is one in which the crown of trees and shrubs burn, often sustained by a surface fire. A crown fire is particularly very dangerous in a coniferous forest because resinous material given off burning logs burn furiously.

Firestorms: Among the forest fires, the fire spreading most rapidly is the firestorm, which is an intense fire over a large area. As the fire burns, heat rises and air rushes in, causing the fire to grow. More air makes the fire spin violently like a storm.

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Effects of Forest Fire

• Loss of valuable timber resources

• Degradation of catchment areas

• Loss of biodiversity and extinction of plants and animals

• Loss of wildlife habitat and depletion of wildlife

• Loss of natural regeneration and reduction in forest cover global warming

• Loss of carbon sink resource and increase in

percentage of CO2 in atmosphere change in the microclimate of the area with unhealthy living conditions

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Effects of Forest Fire

• Soil erosion affecting productivity of soils and production ozone layer depletion health

problems leading to diseases

• Loss of livelihood for tribal people and the rural poor, as approximately 300 million

people are directly dependent upon collection

of non-timber forest products from forest areas

for their livelihood

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Preparedness and Mitigation

• Forest fires are usually seasonal. They usually start in the dry season and can be prevented by adequate

precautions. Successive Five Year Plans have

provided funds for forests fighting. During the British period, fire was prevented in the summer through

removal of forest litter all along the forest boundary.

• This was called "Forest Fire Line" This line used to prevent fire breaking into the forest from one

compartment to another. The collected litter was burnt in isolation.

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Preparedness and Mitigation

• Generally, the fire spreads only if there is continuous supply of fuel (Dry vegetation)

along its path. The best way to control a forest fire is therefore, to prevent it from spreading, which can be done by creating firebreaks in the shape of small clearings of ditches in the

forests.

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Precautions

• To keep the source of fire or source of ignition separated from combustible and inflammable material.

• To keep the source of fire under watch and control.

• Not allow combustible or inflammable material to pile up unnecessarily and to stock the same as per procedure recommended for safe storage of such combustible or inflammable material.

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Precautions

• To adopt safe practices in areas near forests viz. factories, coalmines, oil stores, chemical plants and even in household kitchens.

• To incorporate fire reducing and fire fighting

techniques and equipment

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Use of Remote Sensing in Forest Fire Management

• Remote sensing has been identified as an

effective and efficient tool for monitoring and preventing forest fires, as well as a potential tool for getting an in-depth understanding of how forest ecosystems respond to them.

• Remote Sensing has following advantages

over conventional methods of forest fire

management and prevention.

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Use of Remote Sensing in Forest Fire Management

• Large Area Coverage

• Frequent and repetitive coverage

• Economic

• Semi Automated computer based analysis via algorithm

• Synoptic view in relation to surrounding environment

• Timely estimation of loss of property etc.

• Data available for instant planning and making

new strategies

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Use of Remote Sensing in Forest Fire Management

• Ignition and spread of wildfires depends on fuel moisture and weather conditions as well as on fuel types and topography.

• These parameters are as inputs into fire danger predicting systems that have been developed for fire management, among others for fire

suppression.

• These systems are among others the National Fire

Danger Rating System (NFDRS) in USA ( ) and

the Canadian Forest Fire Danger Rating System

(CFFDRS) in Canada.

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Use of Remote Sensing in Forest Fire Management

• The CFFDRS is also used in Alaska and in some other parts of the world, including

Europe and Asia. Both systems are based

primarily on weather parameters that are point source data which are often acquired in a

sparse network of weather stations.

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Use of Remote Sensing in Forest Fire Management

• The availability of satellite images coupled with the development of geo-statistics and spatial analyses using geographic information technology allows

moving fire danger rating from point-based estimates from weather stations to spatially explicit estimates.

• Indeed, satellite images have the advantages of larger sampling areas, lack of destruction of the studied

resource, gathering data on less accessible areas and are measuring, in essence, the integrated response of vegetation (including fuel) to environmental

influences (including drought).

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Use of Remote Sensing in Forest Fire Management

• Several pre-fire conditions can be monitored using remote sensing.

• The first one is related to the fuel type, which can be mapped, like classical vegetation mapping,

from high spatial resolution optical or radar images.

• These maps can then be linked, within a wildfire threat analysis system, to other pre-fire

conditions variables, such as topography,

proximity to roads and to urban areas, etc...

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Use of Remote Sensing in Forest Fire Management

• Another pre-fire condition, which can be estimated by remote sensing, is the fuel moisture condition.

• We will focus here on live fuel moisture conditions, which are in current fire prediction systems, either directly measured or broadly estimated.

• Dead fuel moisture conditions will also be considered, although they can be more easily computed from

weather data and fuel characteristics, because dead

fuel moisture is in balance with that of the surrounding atmosphere.

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Use of Remote Sensing in Forest Fire Management

• In most of the remote sensing studies on live fuel

moisture estimation, live fuel moisture conditions have been quantified as an absolute measurement of plant water content, through the Fuel Moisture Content

(FMC) or the Equivalent Water Thickness (EWT).

• FMC is defined as the ratio between the quantity of water (fresh weight–dry weight) and either the fresh weight or the dry weight .

• EWT is the leaf water content per unit leaf area which is defined as the ratio between the quantity of water and the leaf area.

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Use of Remote Sensing in Forest Fire Management

• Live fuel moisture conditions have been also quantified indirectly, through the degree of water stress which is expressed in terms of evapotranspiration rates.

To be continued……

References

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