A burning is a process of burning plant biomass (wood, straw, living vegetation). Its effects often exceed the local scale, affecting the composition of the atmosphere and contributing to climate change.
The effects of fire on the natural environment
Naturally occurring forest fires are an integral and necessary part of many ecosystems (as in the Cerrado ), and the organisms that make up the communities in these environments have adaptations to face the fire and even take advantage of it.
Thus, for example, heat from fire may be the necessary factor for certain seeds to germinate, taking advantage of the fact that, in the burned landscape, competition between species will be less and these seeds will have greater access to light, water and nutrients. In many ecosystems where grassland predominates, fire is also an agent in the recycling of nutrients.
The occurrence of forest fires is not limited to the tropics; these phenomena are also common in the Mediterranean climates of Europe, the United States, North Africa, South Africa, Chile and Australia; and also in areas of boreal forest such as Alaska, Canada, Finland and Russia.
Most of the fires, however, occur by human action, for various reasons: clearing pastures, preparing plantations, deforestation, manual harvesting of sugarcane, vandalism, falling balloons, land disputes and social protests, among others . Every year, Brazil loses about 15,000 km2 of natural forests because of fires. In South America, there are 40 thousand square kilometers burned per year.
Burning organic matter produces water, carbon dioxide (CO), carbon monoxide (CO), nitrous oxides, hydrocarbons and particulate matter. As these products are released into the atmosphere, burning causes damage to people’s health. Smoke and fire result in accidents and loss of property and hinder aviation and transportation. The fire, when escaping from control, reaches the public and private patron (forests, fences, transmission lines and telephone constructions etc).
Burns alter or even totally devastate ecosystems: they destroy fauna and flora; by killing the microorganisms from the soil, make them poorer; calcining its surface, reduce the penetration of water in the subsoil. From a broader point of view, the fires are responsible for changes in the chemical composition of the atmosphere and, by extension, have a negative influence on the planet’s climate changes, contributing to the increase of the greenhouse effect and, therefore, to global warming .
The monitoring of fires
At the initiative of the United Nations, an International Center for Global Fire Monitoring (GFMC) was established within the framework of the UN’s International Strategy for Disaster Reduction (ISDR). The spatial extent of the occurrence of burnings in tropical and subtropical South American areas makes remote sensing by satellite the most viable way to monitor these events.
In Brazil, under the Monitoring, Prevention and Control of Burns in Agriculture program of the Ministry of Agriculture and Supply, Embrapa Monitoring by Satellite was requested to study the most critical areas in terms of the occurrence of fires. More recently, since the 1980s, the National Institute for Space Research (INPE) has been developing and improving an operational fire detection system as part of the effort to monitor and minimize the phenomenon.
Brazil is one of the few countries that have an orbital detection system for burning and deforestation foci. In the case of fires, the data are obtained through the thermal images originated from the passage of several meteorological satellites over the Brazilian territory.
These images are made available through the internet in near real time. Geographic Information Systems (GIS) allow the visualization of fires with various information plans. Currently, Inpe’s Real Time Deforestation Detection (Deter) system allows a more accurate evaluation of the fires occurring in Brazil in terms of frequency, location, size and seasonality.
Burnings in sugarcane areas emit large amounts of air pollutants that, transported over long distances, end up damaging other ecosystems. In this way, the ecologically correct aspect of alcohol as a less polluting fuel is overshadowed by the pollution caused by the burning of sugarcane straw.
The burning problem in Brazil
Burnings are used by the human being in several agricultural practices, from those practiced by natives and caboclos to systems of mechanized and intensive production, such as planting sugar cane and cotton.
They are used to clean cultivated areas, to renew pastures, to burn waste, to facilitate the harvesting of sugarcane and to eliminate pests and diseases of plants, etc.
In general, these fires occur in previously deforested areas, in transitional regions between cerrado and tropical forest ecosystems, primarily in the Amazon and Central Brazil regions.
However, as a result of the atmospheric transport of their emissions, there is a spatial distribution of smoke over an extensive area, around 4 to 5 million km2, higher than the area where the fires are concentrated. Burning damages the environment as it affects biodiversity , changes the dynamics of ecosystems, increases soil erosion and
air quality. The environmental impact of burnings has been a concern of the scientific community, environmentalists and society in general, in Brazil and abroad.
The public power, aware of these problems, has developed in partnership with public and private institutions a series of actions, trying to minimize the consequences of the fires, offering technological alternatives for the use of fire in the main systems of agricultural production. It is the example of controlled burning.
By eliminating surplus dry matter resulting from pastures and fields, controlled burning favors regrowth and seed germination and improves the nutritional value and consumption of feria by domestic and wild animals.
Controlled burning must only be carried out in defined areas, with prior isolation by firefighters and under competent technical supervision.