The forest fires They are uncontrolled fires that consume large areas of forests or other types of vegetation. They are characterized by being fires whose combustible material is wood and plant tissues and the wind intervenes in their development..
These fires can be caused by both natural and anthropogenic causes (human actions). In the first case, they occur due to lightning effects in extreme drought conditions with high temperatures, but most are caused by accidental or intentional human action..
They are one of the main causes of degradation or loss of ecosystems, since they can completely eliminate the vegetation cover, as well as the fauna of the area. This increases soil erosion, increases runoff and decreases infiltration, thereby reducing water sources..
There are three basic types of forest fires determined by the type of vegetation, humidity, temperature and wind regime. These are surface fires, canopy fires, and underground fires..
To prevent forest fires, public awareness of the problem and its consequences is essential. In the same way, the environmental nursery, detection and early warning systems, as well as having teams of forest firefighters.
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Forest fires are characterized by occurring in open areas where the wind plays a determining role. On the other hand, the flammable material that feeds them is vegetable matter, such as lignin and cellulose that burn easily.
For them to originate, the combination of a combustible material, heat and oxygen is necessary. The main influencing factors are the presence of dry vegetation and low soil and air humidity, as well as high temperatures and wind..
The plant species at a given site can determine the magnitude and speed of fire spread. For example, conifers such as pines and cypresses produce resins that increase the combustibility of plant material..
Also, some angiosperms from families such as Anacardiaceae and dry grasses (grasses) are excellent fuel. Particularly in tall grasslands the flames spread with great speed.
The relief of the land where the forest fire develops and the direction of the wind are determining factors in the spread and scope of the fire. For example, a fire on mountain slopes with rising air currents spreads at high speed and with flames from great height.
Also, when there is a steep slope, fragments of burning combustible material (firecrackers) move easily downwards..
There are ecosystems where fire is one of their functional characteristics and the species have adapted to periodic fires and are even dependent on fire. For example, in Mediterranean savannas and forests, periodic burns occur that renew the vegetation and promote the germination or regrowth of some species..
On the other hand, many other ecosystems do not tolerate fire, and are severely affected by forest fires. This is the case of tropical humid forests, deciduous tropical forests among others..
The parts of the forest fire are fundamentally determined by the direction of advance of the fire, which depends on the wind. In this sense, a fire front, flanks and a tail are defined, as well as secondary sources..
From the starting point, the fire expands in all directions on the plane, but the dominant direction of the wind defines its characteristics..
It is the front edge of the fire favorable to the dominant direction of the wind where the flames are high and tongues of fire can appear. The latter are longitudinal extensions of the front, which cover the land and expand the fire area..
These are the lateral parts of the fire in relation to the forward front, where the winds affect laterally. In this area, the intensity of the fire is lower and its advance slower.
It is the back of the forest fire and corresponds to its place of origin. At this point, the flames are lower because most of the combustible material has been consumed..
It is common for fire sources to be generated far from the main core, due to the action of fragments of ignited material that move due to the action of the wind or steep slopes..
Forest fires can originate from natural causes or be caused by human actions.
Some vegetation fires occur due to strictly natural causes such as lightning strikes. Likewise, the possibility of spontaneous combustion of certain types of vegetation under suitable conditions has been pointed out..
However, some researchers deny this possibility because the temperatures required to start a forest fire exceed 200 ºC..
More than 90% of forest fires are caused by humans, either by accident, negligence or intentionally caused..
Many wildfires are started by short circuits or overloads in power transmission lines that pass through natural areas. In some cases this happens because weeds are not eliminated at the bases of the towers and the course of the power lines..
A very common cause of wildfires is badly extinguished or uncontrolled bonfires. In the same way, the burning of garbage or cigarette butts thrown on the side of the road.
Man-made wildfires are very common. Thus, there are those caused by people with mental problems who enjoy setting fires (pyromaniacs).
On the other hand, many forest fires are caused deliberately to destroy the vegetation cover and justify the use of the land for other purposes. For example, it has been reported that the main cause of fires in the Amazon is intentional burning to introduce pastures and crops, mainly soybeans..
For ecosystems where fire is part of their natural dynamics, the consequences are generally positive. However, in most cases forest fires have highly negative consequences for the ecosystem and human beings..
Forest fires cause a direct impact by reducing biodiversity in the ecosystem. Fire causes the death of plant and animal species, as well as other organisms such as fungus, mosses, lichens and ferns..
Only those fire-tolerant species (pyrophiles), such as some palms, trees and grasses, are not affected. On the other hand, when the habitat is degraded there is a secondary disappearance of species or many are forced to migrate to survive.
The disappearance or degradation of the vegetal cover and the organic matter of the soil, increases the runoff of the rainwater, decreasing the infiltration. Therefore, the underground water reserves are reduced and the sediments carried from the soil that fill the reservoirs increase..
In addition, as the forest area decreases, its ability to contribute to the production of rain and the capture of environmental humidity is affected..
As the soil is exposed due to the loss of vegetation, the loss through erosion increases. In addition, fire decreases the organic matter in the soil and affects its biological activity, moisture content, and mineral ion exchange capacity..
Forest fires make an important contribution to increasing global warming. The forests that capture and retain atmospheric carbon are destroyed and the retained carbon is released in the form of COtwo, what is a greenhouse gas.
The smoke and particles generated by forest fires cause serious respiratory problems for nearby populations. More directly, people can suffer burns and even death from being caught in forest fires.
Forest fires produce flames that sometimes reach great heights and can affect infrastructures present in the area where they develop or in nearby areas.
When forest fires reach large areas, they sometimes end up affecting nearby residential areas. Therefore, cases of forest fires that end up generating fires of structures are common..
When wildfire flames reach high-voltage power lines, they cause surges. These overloads trigger the system's security mechanisms and power supply to large urban and industrial areas is cut off..
Forests and other ecosystems are a source of food, medicinal, genetic and industrial resources that can be used in a sustainable way. By destroying species in the ecosystem, forest fires cause the loss of these resources.
One value of ecosystems is their potential for tourism. Undoubtedly, this is negatively affected by forest fires, both because of the risk to the safety of tourists during their occurrence, and because of the environmental degradation they produce..
The negative impact of forest fires is also manifested economically, due to the loss of forest resources and infrastructure, the costs associated with health problems, human displacement and subsequent remediation measures..
Forest fires can be classified taking into account various criteria, including the type of plant formation where they occur. In this sense, we speak of forest fires themselves and fires of savanna or grasslands in general..
Regarding the way in which they occur, forest fires are classified into three types: surface, crown and underground.
This type of fire spreads mainly on the ground surface, burning the herbaceous and shrubby vegetation of the understory. Occurs mainly in ecosystems such as non-wooded savannas (no trees).
They occur in wooded areas where the trees have the crowns very close and the fire attacks them. Therefore, the fire progresses from canopy to canopy regardless of the forest floor..
Underground forest fires occur mainly in areas with soils rich in organic matter. For example, in peatlands areas because fire consumes the peat below the ground.
Often times the outbreaks are not detected and are not easy to combat. Thus, peat bogs can burn for weeks under these conditions..
They consist of forest fires that, due to their great magnitude, feed off each other by generating their own development conditions. Very extensive plant formations occur in conditions of extreme drought, so there is abundant combustible material.
Due to their size and intensity, they generate large amounts of heat and produce firestorms. These super fires or sixth generation fires are becoming more common, due to the changing weather conditions on the planet.
For example, during 2019, these types of forest fires consumed millions of hectares in the Amazon, North America, Siberia, Western Europe, Indonesia and Australia..
In some cases, the extreme heat generated in the area causes a low-pressure zone into which masses of air flow. Also, the oxygen fuels the flames and the fire becomes more intense and spreads,
The hot air masses rise like columns, forming a particular type of cloud (pyro cumulonimbus). When these columns collapse, they drag masses of air downward that fuel the fire and cause it to drastically change its direction..
Preventing the occurrence of forest fires requires an integrated program of measures that ranges from promoting public awareness to early warning systems.
The starting point of a forest fire prevention program is to have a citizenry aware of the problem and its consequences. Thus, political pressure can be generated on state administrations to invest the necessary resources.
On the other hand, a conscientious citizen contributes to vigilance and alert, while complying with the necessary preventive measures.
A very common cause of forest fires is the practice of burning stubble and crop residues before cultivating a field. This practice, in addition to affecting the soil and the atmosphere, increases the risk of fires..
To prevent the spread of fires, a firebreak system should be established, either through strips devoid of vegetation or live barriers. These firebreaks are arranged separating sensitive areas from possible sources of fire starting such as roads, populated areas and others..
Controlled pruning and controlled burning of combustible material also helps to prevent the occurrence of forest fires or their spread.,
This method of firebreak consists of laying out strips with evergreen vegetation of pyrophilic species. These are species that are specifically adapted to resist or tolerate fire.
An adequate prevention system must include monitoring the forest and its periodic maintenance. Accumulations of dry material in sensitive areas must be eliminated and even artificial water sources provided.
A fundamental element to prevent the spread of a forest fire is to detect the outbreaks in time. For this, direct surveillance systems, satellite detection technology systems and smoke detection systems are used..
For example, the National Institute for Space Research of Brazil (INPE) detects heat sources through the AQUA satellite. This satellite uses the Modis sensor with a resolution of 1 Kmtwo.
The existence of a forest fire department with suitable and properly equipped personnel is vital to prevent the spread of a forest fire.
According to the National Forestry Commission, 98% of forest fires in this country are of human origin. From 1998 to 2013, the annual average of forest fires exceeded 10,000 events, affecting more than 2 million hectares in total..
In 2019, a total of 7,410 forest fires occurred, affecting more than 600,000 Ha. However, 95% of this area corresponds to herbaceous and shrub vegetation, only 5% involved forests.
Colombia has 18.44% of its territory that is highly susceptible to the occurrence of forest fires. The Orinoquia region is the one with the highest susceptibility to forest fires with 20,000 hectares lost between 1999 and 2002.
In the period from 2002 to 2012, more than 6,000 forest fires occurred, consuming more than 900 Ha. In 2019, more than 500 forest fires occurred in this country.
In Spain there are plant formations where fire is part of its natural dynamics, as is the case of the Mediterranean forest. However, forest fires affect various areas of the national geography.
Between 2000 and 2006, more than 900,000 hectares of the country were burned by forest fires. Between 2007 and 2017, there were more than 8 thousand fire outbreaks per year and the fires themselves exceeded 4 thousand per year.
In 2017, more than 178 thousand Ha were affected by forest fires, including 56 large fires (more than 500 Ha in each case). The region most affected by forest fires is the Northwest (51.57%) and in the province of León (Encinedo municipality) more than 9 thousand Ha were affected.
Between 1973 and 2000, 117 large forest fires occurred in this country, affecting more than 122,000 hectares of forests. The annual forest fire rate increased from 30.7 Ha in the 70s (20th century) to more than 11 thousand Ha in the 90s, due to human causes.
In Venezuela, forest fires are recurrent during the dry season and about two-thirds of its territory faces a high to very high risk. During 2016, more than 200 fires occurred in protected natural areas and in 2019 the number increased to more than 700 forest fires.
On the southern slopes of the Costa mountain range, the semi-deciduous forest has been substantially reduced and fires even affect the cloud forest. For its part, the Perijá mountain range on the border with Colombia suffered in 2016 the worst fire in 15 years.
According to figures from the Ministry of the Environment of this country, more than 8.5 million hectares suffered forest fires between 2005 and 2017. One of the areas most affected by the fires is Patagonia.
In addition, about 30% of the Serranía de Córdoba areas are burned recurrently every year.
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