DAILY CELESTIAL CHALLENGE * THURSDAY * FORCES IN NATURE * Forest fire

yadiinfante (37)in #celestialchallenge • 7 years ago

A forest fire is fire that spreads uncontrollably on forest or wild land, affecting plant fuels, flora and fauna. A forest fire is distinguished from other types of fire by its wide extension, the speed with which it can extend from its place of origin, its potential to change direction unexpectedly, and its ability to overcome obstacles such as roads, rivers and firebreaks.

Causes

The causes that cause a forest fire are classified into five major groups

Intended: according to data from the Government of Spain, represent about 60% of cases (intentionality being understood both when there is fraudulent action and the culprit guilty). The motivations are varied, with the most common being the unauthorized, illegal and uncontrolled burning of agricultural surfaces, either for the removal of stubble or shrubbery (what is known as agricultural burning) or for the regeneration of pastures for livestock .2 After these also highlight the pyromania, hunting, vandalism or personal vendettas. Finally, in some occasions the motivation has to do with driving away animals (wolves, wild boars), urban speculation, animosity against forest reforestation, lowering the price of wood, and several others. It should be noted that the crime of fire is typified in many legislations.
Negligence and accidental causes: they represent 20% -25% of the cases. In this section, agricultural burns (in this case authorized, but in which the authors lost control of the fire spreading through the adjacent forest area) are also among the usual causes. Other causes are cigarette butts and badly extinguished fires, engines and machines, bush burning, power lines, burning of garbage, forestry work, etc.

Lightning: this natural cause represents about 4-5% of cases.
Unknown: in about 15% of forest fires it is not possible to determine the cause.
Reproductions of previous fires: on rare occasions (around 2%) a fire is a reproduction of a previous fire that did not become completely extinct and extends to a new area.

Types of fire

According to where it is propagated

Soil or subsoil fire: Fire is spread by decomposing organic matter and roots. They are almost always burned slowly and in incandescent combustion (little or no flame) as not enough oxygen is available.
Surface fire: The fire is spread by the fuel found on the ground, including leaf litter, grass, shrubs and fallen wood but not immersed in decomposing fallen leaves.

Cup fire:

Antorcheo or Coronamiento: Step of fire of surface to fire of glasses, but only of punctual form in some feet.
Passive Cups: It is the fire that advances through the treetops coupled and dependent on a surface fire, if it is extinguished this stops the glasses.
Active Cups: It is the fire that advances through the crowns of the trees regardless of the surface. It can only be attacked indirectly and usually requires a wind greater than 30 km / h and proximity of glasses (high apparent density of glasses and long glasses).

According to the size

Large forest fires (GIF). Thus, fires that exceed 500 affected forest hectares are defined.3 They are characterized by a behavior that is outside the capacity of the extinction system, either because of the high flame lengths, because of the high propagation speeds or because of the presence of fire fire activity. These fires are not very frequent but they are the real problem, since they burn enormous surfaces in a few hours or days.
Normal fires. Those with an extension between 1 ha and 500 ha. In Spain, about 35% of the declared fires belong to this type.
Conatos. Those that do not exceed 1 hectare of burned surface. In Spain they represent almost 65% of the total. The higher the percentage of fires that remain in conatus, the more effective it is assumed in extinction systems.4

According to the element that governs the fire:

Fuel, gas, topographic, driven by wind

Consequences

Natural forest fires have always been a normal element in the functioning of ecosystems. Fire has allowed the regeneration of diverse ecosystems and the production of a series of habitats in which different organisms can thrive. However, the enormous proliferation of fires due to human activity in recent decades exceeds the capacity for natural recovery.

Among the various forms of impact that forest fires produce, the following can be highlighted:

Erosion of the soil when the vegetal layer disappears. This lack of protection of the soil against the high erosiveness of rainfall causes large losses of soil and nutrients, but this is not only the effect on the soil system. High temperatures modify the biological and chemical composition of the soil.
Death or physical damage to a part of the animal population of the area, especially the one that has less mobility (invertebrates, offspring of birds or mammals, etc.), burns or respiratory poisoning.
On some occasions, death or physical damage to people who intervene in the extinction of fires or who are trapped by it.
Occasionally, damage to the health of nearby human populations.18
Destruction of goods and infrastructure (houses, warehouses, electricity and communication poles, etc.)
Temporary court of communication channels.
Economic losses due to the loss of wood and / or food products, as well as the costs of regeneration work in the affected areas.
Alterations, sometimes irreversibly, of the balance of the natural environment.
Pollution of rivers that receive the rainwater that crosses the burned area, dragging particles and ash in suspension.
Impact on the landscape.