Uncontrolled combustion is commonly called fires. Forest fires are the same process, but in an area densely planted with trees. Forest fires are common in green farms rich in grasses, shrubs, dead wood or peat. The causes and consequences of such disasters vary from region to region.
Fossil coal indicates that fires began shortly after the appearance of land plants 420 million years ago. The occurrence of forest fires throughout the history of earthly life gives rise to the assumption that fire should have a pronounced evolutionary effect on the flora and fauna of most ecosystems.
Types and classification of forest fires
There are three main types of forest fires: high, low and underground.
Riders burn trees all the way to the top. These are the most intense and dangerous fires. They, as a rule, strongly affect the crown of trees. It is worth noting here that such a fire in coniferous forests is the most dangerous because of the strong combustibility of trees. However, it also helps the ecosystem, because once the dome burns out, sunlight can reach the earth, supporting life after the disaster.
Ground fires burn the lower tiers of trees, shrubs and ground cover (everything that covers the ground: foliage, brushwood, etc.). This is the lightest type that does the least damage to the forest.
Underground fires occur in deep accumulations of humus, peat and similar dead vegetation that become dry enough to burn. These fires spread very slowly, but are sometimes the most difficult to extinguish. Sometimes, especially during prolonged droughts, they can smolder underground throughout the winter, and then reappear on the surface in spring.
Photo of a mounted forest fire
Causes of occurrence
Forest fires can be caused by natural and artificial causes.
Natural causes mainly include lightning, volcanic eruptions ( active volcanoes in Russia ), sparks from rock falls and spontaneous combustion. Each of them is a source of ignition of trees. Favorable conditions for the spread of forest fires are caused by high temperature, low humidity, an abundance of combustible materials, etc.
For artificial reasons, a fire in the forest may break out when a fire, such as a flame, cigarette, electric spark or any other source of ignition, comes into contact with any flammable material in the woods due to human neglect, neglect or intent.
There are a number of characteristics of forest fires. Let us briefly dwell on them. As mentioned above, according to the nature of the fire, forest fires are divided into: top, bottom and underground.
According to the rapidity of advancement, top and bottom fires are divided into fluent and steady.
The underground fire is considered to be weak, affecting no more than 25 cm. Medium - 25-50 cm, and strong if burned more than 50 cm.
Forest fires are also divided depending on the zone of their distribution. A fire is considered catastrophic, in which the area covered by the fiery elements exceeds 2000 hectares. The major ones include fires in the territory from 200 to 2000 ha. From 20 to 200 ha, disaster is considered medium. Small - from 2 to 20 hectares. Tanning is a fire that does not go beyond 2 hectares.
Extinguishing forest fires
The behavior of fire depends on the method of ignition, the height of the flame and the spread of fire. In forest fires, this behavior depends on how the fuel (for example, needles, leaves and branches), weather, and topography interact.
Initiated ignition will continue to burn only if temperature, oxygen and a certain amount of fuel are present. Together, these three elements are said to constitute a “fiery triangle”.
To extinguish a fire, one or more elements of the fire triangle must be removed. Firefighters should proceed as follows:
- cool trees below the combustion temperature by using water, foam or sand;
- turn off the oxygen supply with water, moderator or sand;
In conclusion, burning elements are removed, trees are cleaned before the advancing fire.
Fires are the main cause of land degradation and have numerous adverse environmental, economic and social consequences, including:
- loss of valuable forest resources ;
- watershed degradation;
- extinction of plants and animals;
- wildlife habitat reduction and wildlife depletion;
- slowing down natural regeneration and reducing forest cover;
- global warming ;
- increase in the proportion of CO2 in the atmosphere;
- change in the microclimate of the region;
- soil erosion affecting soil productivity and fertility;
Ozone depletion also occurs.
Forest fires in Russia
According to statistical reports for the period from 1976 to 2017, 11,800 to 36,600 forest fires are recorded annually on the protected territory of the forest fund of the Russian Federation on an area of 235,000 to 5,340,000 hectares (ha). At the same time, the area of forests massively attacked by fire annually ranges from 170,000 to 4,290,000 ha.
Forest fires cause irreparable damage to natural resources. Fires of this type make up from 7.0% to 23% of the total area of the forest fund, which is subjected to fire attacks every year. On the territory of Russia, ground fires are most widespread, causing damage of various intensities. They are found in 70% - 90% of cases. Underground fires are the least common, but they are the most destructive. Their share is not more than 0.5% of the total area.
Most forest fires (over 85%) are of artificial origin. The share of natural causes (lightning discharges) is about 12% of the total number and 42.0% of the total area.
If we consider the statistics of the appearance of fires in different areas of the Russian Federation, then in the European part they occur more often, but in a smaller area, and in the Asian part - vice versa.
The northern regions of Siberia and the Far East, which account for about a third of the total forest fund, are located in uncontrolled areas where fires are not recorded and are not converted into statistical materials. Forest fires in these regions are indirectly estimated according to state forest inventory data, which include information on burned areas in all forestry and constituent entities of the Russian Federation.
Forest Fire Prevention
Preventive measures will help to avoid this kind of phenomenon and preserve the green wealth of the planet. These include the following:
- installation of firing points;
- arrangement of fire sites with storage of water and other extinguishing agents;
- sanitary cleaning of forests;
- assignment of special zones for tourists and vacationers;
It is also important to inform citizens about safe behavior with fire.
- Monitoring, as a rule, includes various kinds of observations and statistical analysis. With the development of space technology in the world, it became possible to observe events from the satellite. Along with observation towers, satellites provide invaluable assistance in the system of detection of flashpoints.
- The second factor is that the system must be reliable. In an emergency organization, this means that the number of false alarms should not exceed 10% of all observations.
- The third factor is the location of the fire. The system must find the fire as accurately as possible. This means that the permissible accuracy does not exceed 500 meters from the actual location.
- Fourth, the system should offer some estimates of the spread of fire, that is, in which direction and at what speed the fire moves forward, depending on the speed and direction of the wind. When regional dispatch centers (or other fire departments) receive public smoke observations, it is important that authorities be aware of the general pattern of fires in their area.
Video about forest fires