Controlled Burning

Background Controlled Burning (also called Prescribed Burning) is an important and cheap management tool to manage rangelands. Fire is able to "clean" the pastures, removing ungrazed grass, a part of the litter and controlling the density of woody plants (trees & shrubs). Fires also stimulate the growth of perennial grasses in savannas and provides nutritious regrowth for livestock. Controlled burning prevents uncontrolled and more destructive fires. On the other hand, fires have a destructive effect on different vegetation communities and animal species, reduce the organic matter recycling to soil and result in a decrease of soil fertility in the long term. Environmental consequences of rangeland and grassland fires depend on the environmental context and conditions of application. | Background Objectives Techniques Costs Targeted Livestock System Impact Context of Application Monitoring: EIA, Indicators References See Also

Objectives

Under climate with a sufficient dry season, part of the vegetation, particularly grasses and annual herbs constitutes a dry and combustible material. Pastures and rangelands threatened by fire must be burned at a choosen period, and on choosen areas.

Controlled burning reduce hazard of violent or extended bushfires consumming the combustible lower layer at an appropriate humidity stage. A moderate burning is not so aggressive to the plants and animals, adapted in these environments to periodic fires.

As many grass species are fire tolerant, often much more than tree species (specially at young stage), burning is a tool to maintain a balance between grass cover and ligneous vegetation. This objective is the maintenance of the pastures on opposition to the forest and an open landscape with the subsequent ecosystems.

Techniques

Voluntary burning of vegetation when this is not completely dry. The temperature reached must just have the expected effects . Burning is practiced when the wind is soft. An early burning stimulate grass regrowing.

If the expected result is the control of tree populations, fires must be stronger.

In arid and semi arid regions, specially in annual grasslands, fire must be forbidden. By contrast, controlled burning in perrenial grasslands can be used as an important rangeland management tool.

Costs

The main costs are related to the workers mobilized to control the progress of burning in the vegetation and the the required equipment (vehicles or other means of transport, drip-torches and fuel). Controlled burning can also be done using incendary devices dropped from light aircraft. This technique is practised in Australia where large areas that need to be covered mean that the use of aircraft in this way is cost effective.

Targeted Livestock System

Grazing and Communal Mixed Systems in sub-humid and humid tropical and temperate zones

Grazing System

LGA | LGS1 | LGS2 | LGS3 | LGH1 | LGH2 | LGH3 | LGT1 | LGT2 | LGT3
N | Y | Y | Y | Y | Y | Y | N | N | N

Mixed System

MCG | MCR | MCC | MFF | MEF
Y | Y | Y | Y | N

Industrial System

IFP | IPL | IPG | IRM | IDU | ISL | ITN | IMP
N | N | N | N | N | N | N | N

Impacts

- Positive environmental impact

- Reduction of fire hazard in grassland and rangeland.
- Control of ligneous plant populations.
- Maintenance of grassland ecosystems (including wildlife).

- Negative environmental impact

- Destruction of plants and animals susceptible to fires.
- Loss of organic matter, loss of soil fertility.
- Emission of CO2, destocking of carbon.
- Reduction plant cover during dry season, exposure ofsoil to erosion factors.

- Impact on livestock productivity

- In savanna, burning is used to clean pastures and purchase grass regrowth nutritious to livestock.
- Maintenance of pastures if correctly applied, improving carrying capacity and quality of forage.

Context of Application

- Unfavourable factors:

- Insufficient awareness of population and technician on fire impacts.
- Low density of population.
- Hunting and poaching.
- Insufficient number of people to control burning.
- Unadapted and rigid legislation on bushfire.

- Favourable factors:

- Consciousness of population to fire impacts on environment.
- Limited land resources.
- Important grazing activity.
- Skill of herders.
- Efficient local organization of farmers and producers.

Monitoring: EIA, Indicators

- Areas treated by controlled burning.
- Areas accidentally burned.
- Composition of vegetation, interannual evolution of key species.
- Density of ligneous cover.
- Grass production , carrying capacity.

References

Bellefontaine R., Gaston A., Pettrucci Y. 1997. Aménagement des forêts naturelles des zones tropicales sèches. Cahier FAO Conservation N°32. FAO, Rome, Italy, pp. 316.

IEMVT-CIRAD, 1990. Les feux de brousse – Les fiches techniques d’élevage tropical. Ministère français de la coopération et du développement. 1990, fiche n’3.

Pastum, septembre 1998. Numéro spécial double 51 – 52 : Brûlages dirigés, 121 p., publié par l’Association Française de Pastoralisme.

Louppe D., 1992. Le feu, mieux comprendre pour mieux lutter. IDEFOR, Abidjan, Côte d’Ivoire, pp. 27.

See Also

Firebreaks

Use of Fire to Maintain Pasture

Prescribed Burning: US Fish and Wildlife Service.Sherburne National Wildlife Refuge. http://www.fws.gov/r3pao/sherburn/BURN.HTM Sherburne National Wildlife Refuge conducts a series of prescribed burns each year as part of its habitat management program.

Wildland Fire Management http://fire.nifc.nps.gov/bia/

International Association of Wildland Fire. http://www.wildfiremagazine.com/

Environmental Science and Technology (1995). Biomass Burning: A Driver for Global Change.
http://asd-www.larc.nasa.gov/biomass_burn/globe_impact.html

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