Use of Fire as a Tool

Environmental Issues In regions which have a long enough dry season, the risks of vegetation fire are temporarily very high. The fire has various causes, it can be an accident, an intentional fire to clear the land ( for movement, to allow hunting, to chase away harmful animals, to prepare the field, to clear the pasture of uneaten hay and to promote the production of nutritious re-growth, sometimes also for evil intent or simply to see flames) | Environmental Issues Controlled Burnin. Prevention of Bush and Forest Fire Carbon Sequestration. Firebreaks Prevention of Bush and Forest Fire Positive Environmental Effect of Grazing Negative Environmental Effects Mixed Species Herds

The multiple effects of fire on the environment have been widely studied and described. Their environmental impact and interest for livestock farming depend on the agro-climatic context.

In semi-arid regions or where there is a very marked dry season, fires are all the more violent since the vegetation is abundant and dry. They cause major damage to the vegetation and soil if they are fierce: they can kill bushes and trees and destroy part of the seedlings and the litter covering the soil and the organic matter in the top centimetres of the soil

Biological activity is brutally reduced by the heat. Sensitive plants are progressively eliminated by successive fires.

- In sub-humid and humid tropical regions, fires are widely used to control proliferation of certain species or categories of plants, mainly tree species, and to maintain an equilibrium in the vegetation between grasses, which are useful to livestock, and trees. This is especially the objective of savannah grassland fires, which maintain the fire-tolerant grass carpet. A savannah regularly covered by bush fires has stable flora and each vegetation unit tends to remain true to itself indefinitely (J. César, 1992). Cessation of fire is followed in these humid and sub-humid tropical areas by bush encroachment and evolution towards woodland vegetation, useless for livestock farming.

- In humid tropical regions where grasslands have been sown after clearing the forest, fires are considered harmful since they destroy forage production and are not tolerated by the selected grasses.

From the environmental point of view, issues of vegetation fire linked to livestock farming have different objectives:

- Fires to maintain grazing land vegetation, carried out in precise conditions: see Controlled Burning.
- Techniques for fire prevention: see Prevention of Bush and Forest Fire.
- Emission of CO2 linked to bush fires and carbon sequestration techniques – see Carbon Sequestration.

Prevention of Bush and Forest Fire

Prevention of vegetation fires, whether it is a question of natural vegetation such as savannahs or dry forests, or maintained grasslands, is done in various ways:

- Creation and then maintenance of fire breaks (see Firebreaks).
- Practice of early fires, in conditions where the effects of fire remain limited (see Controlled Burning).
- Reduction of combustible biomass by grazing before the high risk season.

Impacts

Positive environmental impact of grazing

In regions where there is a dry season, even partial elimination of straw reduces considerably the risks of fire. When the vegetation is dry forest with important bush undergrowth below, clearing this undergrowth and reducing bush density helps preserve the forest from fire. Frequent passage of browsing animals such as goats helps control small trees. Grazing animals such as sheep reduce the amount of grass, which; once standing dry, burns easily (see Mixed species herds).

Negative environmental impact

In humid tropical savannahs, reducing the intensity of bush fires sets off a progressive evolution of the vegetation to forest. Even though for the forester or environmentalist, this evolution is not degradation, the livestock farmer considers that the natural pasture is becoming degraded since the grass carpet disappears and hence livestock are gradually chased away from these areas. The costs of regeneration of grazing land can become very high.

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