Forest Fires: Causes, Types and Effects

Forest Fires

1. Definition of Forest Fire:
   • A forest fire, also known as a wildfire, is characterized as uncontrolled and freely spreading combustion that consumes natural fuels.
2. Impact of Fire on Forests:
   • Fire has played a significant role in shaping and managing many forest ecosystems worldwide.
   • Some forests have evolved to withstand and even depend on frequent fires, while others are vulnerable to the destructive effects of wildfires.
3. Wildfire:
   • When a fire burns out of control, it is termed as a wildfire.
4. Historical Presence of Forest Fires:
   • Forest fires have occurred throughout history, ignited and burned naturally through forests.
5. Variable Effects of Fire:
   • The effects of fire on forests vary significantly.
   • Fire can be beneficial for some ecosystems while catastrophic for others, depending on factors such as climatic conditions and vegetation type.
6. Extent of Damage:
   • Every year, millions of hectares of forests worldwide are consumed by fire.
   • This leads to significant economic losses due to burnt timber, degraded real estate, high suppression costs, damage to environmental and recreational values, and loss of life.

Types of Forest Fire

Forest fires are not always same; they may differ, depending upon its nature, size, spreading speed, behavior etc. Basically forest fires can be sub grouped into four types depending upon their nature and size –

Surface fires

• Common forest fires burning undergrowth and dead material along the forest floor.
• Burns surface litter, loose debris, and small vegetation.
• Generally beneficial for forest growth and regeneration, but can become destructive if they grow in size, engulfing undergrowth and middle storey.

Underground fires

• Low-intensity fires consuming organic matter beneath and surface litter.
• Spread through the organic material on top of mineral soil, burning entirely underground.
• Slow-spreading and difficult to detect, may continue burning for months, destroying vegetative cover.
• Also known as muck fires.

Ground fires:

• No clear distinction from underground fires, may transition from smoldering underground fires.
• Burn root and surface material, including herbaceous growth and organic layers.
• More damaging than surface fires, can destroy vegetation completely.
• Hard to detect and slow-moving, making firefighting challenging.

Crown fires:

• Unpredictable fires burning the tops of trees, spreading rapidly by wind.
• Often initiated by surface fires.
• Advance from top to bottom of trees, sometimes independent of surface fires.
• Can race ahead of surface fires, posing grave danger to firefighters.
• Controllable only when they drop to the ground, usually fast-moving and spectacular.

Firestorms

• A firestorm is an intense fire that spreads rapidly over a large area.
• As the fire burns, heat rises, and air rushes in, fueling the fire’s growth.
• Increased air intake causes the fire to spin violently, resembling a storm.
• Flames and burning embers are ejected from the base and top of the fire, igniting smaller fires in surrounding areas.
• Temperatures inside firestorms can reach around 2,000 degrees Fahrenheit, indicating the extreme heat generated by these phenomena.

Components of Fire

• Fire requires three components: fuel, heat, and oxygen, which together form the “fire triangle.”
• In forests, fuel (vegetation) and oxygen are naturally abundant.
• Heat is the component that initiates fires and can be supplied by natural or artificial means.

Causes of Forest fire

• Over ninety-five percent of forest fires are caused by human negligence or unknowingly.
• The remaining fires are caused by natural factors such as lightning or extreme temperature rises, though these are rare.
• Anthropogenic causes are predominant globally, while natural causes are more common in remote areas.

Classification of Causes:

• Forest fire causes are classified as natural or artificial based on the source of heat.
• Natural causes include lightning, volcanic explosions, and friction (e.g., from rolling stones).
• Anthropogenic causes are further divided into deliberate and unintentional or accidental causes.

Effects of Forest Fire

Fires are a major cause of forest degradation and have wide ranging adverse ecological, economic and social impacts, including:

1. Damage to Forests:
   • Loss of growing stock, leading to long-term ecological damage.
   • Reduction in biodiversity due to habitat destruction.
2. Environmental Degradation:
   • Increase in soil erosion, scorching of soil, and reduction in permeability and water-retaining capacity.
   • Volatization of nutrients like Nitrogen, affecting soil fertility.
3. Human Impact:
   • Direct loss of life and property, with extreme fires destroying houses and causing fatalities.
   • Examples include the Victoria fires in Australia (2003) and Greece fires (2007) resulting in significant human casualties.
4. Health Issues:
   • Smoke generated by forest fires leads to breathing problems, skin irritation, and reduced visibility.
   • Forest fires can exacerbate respiratory conditions and cause other health-related problems.
5. Secondary Hazards:
   • Extreme forest fires can create conditions leading to floods and landslides, causing further loss of life and property.
   • Immeasurable losses include impacts on timber increment, soil fertility, employment, water sources, and biodiversity.

Forest Fire Management Practices Used by Forest Departments

Traditional Practices

1. Fire Lines:
   • Development and maintenance of Kachha (covered) and Pucca (open) fire lines to prevent fire spread.
2. Controlled Burning:
   • Scheduled burning of leaf litter, twigs, and undergrowth during the dry season to maintain forest health.
3. Fire Terracing:
   • Controlled burning along roadsides and paths to prevent unintentional fires caused by human activities.
4. Back or Counter-Fire:
   • Igniting a strip of unburnt area towards advancing fire to create a barrier and reduce fuel material.
5. Rock Walls:
   • Construction of permanent fire control rock wall barriers to prevent fire spread.
6. Fire Watchers:
   • Deployment of forest watchers during fire season for monitoring and sweeping dead leaves.
7. Fire Watch Towers:
   • Early detection of fires through forest lookout towers, enabling prompt firefighting responses.
8. Soil and Moisture Conservation Works:
   • Implementation of measures like contour trenches and gully plugs to increase soil moisture and reduce fire frequency.

Modern Practices

1. Fire Alert System:
   • Geospatial technology-based system to detect and alert forest officers about fire points.
2. Mobile Squads:
   • Intensive patrolling using vehicles to detect and suppress fires.
3. Leaf Blowers:
   • Use of petrol/diesel-powered leaf blowers to clear fuel material and create fire breaks.
4. Communication Devices:
   • Wireless communication systems for timely reporting and coordination in fire control.
5. Community Participation:
   • Involvement of local communities through Joint Forest Management Committees in fire prevention and awareness programs.

Benefits of Controlled Forest Fires

1. Ecosystem Renewal: Forest fires can clear out dead vegetation, allowing new growth to emerge. This renewal process can be vital for maintaining the health and diversity of the ecosystem. Some plant species even rely on fire to germinate their seeds.
2. Nutrient Cycling: The intense heat of a fire breaks down organic matter, releasing nutrients into the soil. These nutrients become available for new plant growth, enriching the soil and promoting regeneration.
3. Control of Invasive Species: In some cases, forest fires can help control the spread of invasive plant species by destroying their seeds and reducing their competitive advantage over native species.
4. Wildlife Benefits: Some wildlife species have evolved to depend on periodic fires. For example, certain bird species may rely on open habitats created by fire, and some mammals may benefit from the increased availability of food following a fire.
5. Reduced Fuel Load: Regular, low-intensity fires can help reduce the buildup of flammable vegetation, lowering the risk of more severe fires in the future. This process, known as prescribed burning, is often used as a management tool in fire-prone areas.
6. Cultural and Traditional Practices: In some indigenous cultures, fire has been used for centuries as a tool for land management. Traditional burning practices can help maintain the health of ecosystems and promote cultural heritage.

Forest Fire: The Indian Scenario

• As per FSI analysis more than 95 percent of the forest fires in the country are man made. The Forest Survey of India, 1995 data on forest fire attribute around 50 percent of the forest areas as fire prone.
• According to assessment of the Forest Protection Division of the Ministry of Environment and Forest, Government of India, fires in India annually affect 3.73 million hectares of forests.
• The vulnerability of the Indian forests towards fire varies from place to place depending upon the type of vegetation, the climate and various other factors- both natural as well as man made.
• In India, broadly 4 fire clusters have been recognize. These are as follows:
  • North Western Himalayas: Forest fires in North Western Himalayas is primarily due to preponderance of pine forest and accumulation of thick flammable litter. These forest are prone to forest fires in summer months due to accumulation of large quantity of pine needles.
  • North East India: Majority of forest in these area are community owned and people primarily practice slash and burn or shifting cultivation causing wide spread annual forest fires.
  • Central India: Extensive forest tracts dominated by dry deciduous and moist deciduous Teak and Sal forests in Central India get annually burned owing to use of fire for promoting collection of non timber forest produces.
  • Western Ghats and Eastern Ghats: In spite longer wet season and higher moisture regime, moist deciduous forests and semi evergreen forests in Western and Eastern Ghats gets burned frequently due to various biotic activities.