Operational Significant Event Imagery (OSEI)
The following significant events were identified by Satellite Analysis Branch meteorologists and reviewed by the OSEI support team:
NESDIS/OSEI NOAA-14 POES AVHRR LAC satellite image, 9 January 2001.
Heat signatures (red) and smoke (light blue) are visible from fires burning in Congo, Sudan, Central African Republic, and Uganda.
The background of fires in Sudan and the Central African Republic is highlighted below. These reports are part of the Special Report on Forest Fires of the UN-FAO Forest Resources Assessment (FRA) 2000. The complete report is currently prepared by the GFMC and the FAO.
The fire environment Climate and fire regimes The dry season starts two to three weeks after the rains end in Northern Sudan, i.e. November to April/May. Tall and short grasses are desiccating increasingly during the dry season. An increased wildfire hazard is associated with low humidity, high fuel loads and the presence of moving graziers. Annual wildfires are common and spread rapidly due to NE winds and flat terrain. This is the case of central, western and southern Sudan. Repeated fires persist if the hot dry weather continues, i.e. late rains.
Ecological role of forest fires In the high-rainfall savanna ecosystems of southern Sudan fires kill certain fire-sensitive trees, e.g. Isoberlinia doka, Daniellia oliveri, etc. and reduce the growth of other species. Fires may reduce gum yields from Acacia senegal by up to 50%. This is considered a big economic loss. In the average fires affect about 70% of the open rangelands.
Fires may also encourage the spread of some species, e.g. Acacia mellifera in central Sudan on clay soil where the “Acacia-grassland cycle” takes place: The occurrence of Acacia alternates with tall grasses: Acacia takes over if the fires are of low severity. Grasses become dominant with increasing fuel loads and high-intensity fires.
Impacts of wildfires
Lightning fires or fires caused by nomads often damage or destroy whole villages with huts that are built from grass and wooden materials. This problem is very common in central Sudan. Villagers in many instances are caught by surprise.
Fires statistics for the time period 1980 to 1999 for the Sudan are lacking, except for limited incidents in Jebel Marra where some 3000 feddan (1 fed. = 0.42 ha) of Cypressus lusitanica have been destroyed in the 1990s. Usually large tracts are swept over by wild fires in the central and western Sudan. Presently nothing is known on the situation of southern Sudan where fires presumably are set by the army to improve visibility and control of the terrain. More than 60 million ha are affected annually.
Organizational set up
A fire management organization is not in place. However, the traditional system of constructing or maintaining forest fire lines (firebreaks) is adhered to through an annual program budgeted for, but necessary funds are always short. Also ground vegetation specially grasses may dry very fast after the end of the rainy season and the firebreak programme is never completed in time.
Fire lines, which usually form the boundaries of these reserves, protect Government forest reserves by law. The law states that fire lines should be at least 2m wide but these are inadequate and normally 5-8 m wide lines are cleared but still fires may jump over. Cleaning fire lines is an expensive operation.
In the colonial time and up to the end of sixties the Native Administration under the supervision of the Range and Pasture Department in close collaboration with the Forestry Department maintained a firebreak network extending North-South over North Kordofan and North Darfur to protect grazing lands and gum gardens. Usually 4-m wide lines are cleaned and spaced parallel to each other and separated by an 80 m. wide area which is burnt just before the end of the rains. This pattern is repeated systematically over the semi-arid lands. Early warning systems, detection and monitoring systems of forest fires are not available. No voluntary fire fighters are available but people and communities are obliged by the forest law to report and help in fighting wild forest fires. Fire research is absent.
Use of the prescribed fires
Prescribed burning is used in natural forests in Western Sudan (Jebel Marra) and used to be practiced as early burning in the southern Sudan but stopped due to the war. The method of backfiring for controlling a wildfire is forbidden except for certain conditions and under control of appropriately trained foresters.
Sustainable land use practices to reduce wildfires
Very wide fire lines (50 m) have been used to separate blocks of Eucalyptus plantations in the Khartoum green belt. Fuelbreaks (greenbelts) consisting of teak (Tectona grandis) were used in the south to protect fire-prone species. In traditional agricultural areas people and farmers are guided by extension workers to protect their villages and lands. At present there is no method other than burning to clear forest lands for cultivation under rains. The forest law however prevents wasteful burning and obliges cultivators to make use of cleared woody materials (shrubs, trees) by converting it into useful products, e.g. charcoal.
Public policy concerning fires
The forest policy of 1986 emphasizes the protection of forests against fires. The forest law of 1989 prohibits trespassing of people and their animals into reserved forests and prohibits the carrying of ignited material into the forests, making of fires for cooking or otherwise in or near forest and obliges people to help in extinguishing forest fires.
Reduction of fires will definitely conserve the natural resources of the country and will improve the growth of many tree species.
Needs of fire management can not be detailed here due to the complexity of different environmental conditions and the needs for different management techniques. The very large size of the country, the various local factors and weather conditions, the rapid trends towards repeated strong droughts and desertification, the increase in population and domestic animals, the displacement of rural people towards cities, the expansion of unplanned rain-fed cultivation, the poverty of the people, the unawareness of the decision makers regarding forest conservation these are all major problems and impediments.
Sudan needs extension capabilities to teach the people how to protect their lands. Research is needed to find out safer methods for preparing agriculture or forest lands for cropping or forest plantations. Above all trained personnel and supporting equipment is needed for transport, detecting and fighting forest fires.
Goldammer, J.G. 1991. Integrated fire management, Jebel Marra Forest Circle (Sudan). Report for GTZ P.N. 86.2595.6-01.100.
Bayoumi, Abdel Aziz M. S. Sudan country report on forest fires (2000). International Forest Fire News No. 24 (in press)
Central African Republic
Vegetation and fire environment
In the Central African Republic (RCA), there are three major vegetation formations as defined by UNESCO (White 1983): Sudanian, Guineo-congolia/sudania, and Guineo-congolia. These three formations form lateral bands covering the dry savannahs in the north, the wet savannahs in the centre and the humid forests in the south. The Sudanian region is predominantly open woodland savannahs.
The transition zone of the Guineo-congolia/sudania consists of secondary savannahs and woodlands with some open forest. These savannahs are deemed to be fire-maintained. In areas where there has been a decline in population, a regrowth of woody biomass has occurred. In the southern part of this transition zone, mosaics of dense forest and secondary savannahs are found.
The Guineo-congolia region is predominantly dense humid semi-evergreen forests (both terre firme and flooded), which are rarely subjected to fire, and of included savannahs. These included savannahs are very important in terms of biodiversity. Running north-south, the central Plateau of Ouadda is dominated by remnant forest. A more detailed partition of the vegetation types has been undertaken by Boulvert (1986). Fire activity starts in the northeast of the country around November, and moves southwest following the Harmattan winds, reaching a peak in late December, or early January. The onset of rains in March terminates the fire season.
Major fire impacts
While there are no official data available, there is a perception at government levels that vegetation fires have various detrimental impacts. Since the economy relies heavily on small-scale agricultural production, the accidental destruction of cultures is of major concern. The intensive use of fire throughout the region for agricultural practices, hunting and pastoralism threatens the sustainability of natural resources. Soil erosion on the hills around the capital, Bangui, has been linked to cultivation and intensive burning. Visitors to Bangui will note the poor air quality due to smoke particles in the dry season. The deposition of acid rain over the forests downwind of RCAs savannahs has been linked to the burning of savannahs.
Little or no data exist to document the impact of fire over the last 20 years. A suite of scientific experiments was carried out in the mid-1990s on the sources of atmospheric pollutants in the regions. Under this initiative, EXPRESSO (Experiment for Regional Sources and Sinks of Oxidants), a satellite receiving station capable of receiving the NOAA-AVHRR data and detecting fires, was installed at Bangui. Data were collected for the 1993-94 and 1995-96 dry seasons. For the 1994-95 dry season, a study by Eva and Lambin (1998) using satellite data estimated that just over 43 percent of Sudanian savannahs burned and 58 percent of Guineo-congolia sudanian savannahs burned. This corresponds to an area affected by fire of 86,000 km² and 191,000 km², respectively. The 1994-95 dry season is considered to represent an average fire season.
The area of forest affected by fires is difficult to assess in the absence of a suitable forest database. The work done by Eva and Lambin (1998) detected 2486 cases of fires in “forested” areas. However, a close inspection of the data revealed that all these fires were on the edge of the forest domain. Some were likely for the purposes of establishing coffee cultures. It is not, however, possible to quantify these in terms of area of forest burned.
Operational fire management
Fire management is undertaken at the local level, where the decision to burn certain areas is decided at the village level. This usually covers areas within five kilometres of the road network. The government has tried to encourage a conservative approach to burning by the use of radio campaigns. Realising that lack of knowledge was one of the main obstacles to effective fire management, the RCA government, with the help of the ADIE (Association pour le Developpement de lInformation Environmementale) and the EU Joint Research Centre, has installed a permanent satellite receiving station at Bangui. The objective is to work with the CNLIFBAC (Comite National de Lutte contre les Incendies, Feux de Brousse et Autres Calamités) to document the occurrence of fires in different vegetation strata, and to predict regions at risk of fires.
The data will be used to sensitise public opinion to the problems of fire using TV and radio campaigns and to organise prescribed burning. At the same time, the data can be used to better organise the campaign against illegal hunting. Under the same initiative, a study will be carried out on the economic effects of fire on the country.
Use of prescribed fire
Fire is used extensively across RCA. There are three main activities.
Large scale poaching
: This has its greatest impact in the north and north east of the country. The open savannahs of the Northeast, on the Sudan border, see large fire fronts (50 km) every year, moving southwest as the season progresses. The fires start on the frontier with Sudan in November and move southwest, arriving at Bakouma in February. These are thought to be due to large scale poaching activities. A similar process occurs in the north of the country on the frontier with Chad. Fires of several kms size advance down towards the Massif des Bongo during November, December, and January. This area is comprised of several national parks. The fires are smaller than those found in the Northwest as the landscape is more fragmented with rivers and woodlands. The Plateau of Ouadda, south of the Massif, sees many large hunting fires later in the season (January to March). This remnant forest area is a home to bush game.
: Fires are used to stimulate re-growth for cattle in the dry season. This occurs around the town of Bambari (central RCA) and on the routes from Northwest RCA (a livestock breeding area) to the markets in the south. The herdsmen light fires along the route both to stimulate regrowth and to facilitate passage. These fires tend to be at least five km from the road network. The fires are small in size and start in December and continue until March.
: These small fires occur across the country in December and January, but are predominantly close to the road network, being lit to prepare the fields for agriculture. At the same time, farmers burn the area around their crops and villages earlier in the season to avoid accidental fires caused by the passage of pastoralists. The conflict between the two groups, pastoralists and villagers, is a well-known one.
The CNLIFBAC intends to propose a “fire calendar” to the population to manage the spread of fire across the country.
Sustainable land-use practices employed in the country to reduce wildfire
Burning around villages before the migration of cattle through the areas is carried out to reduce the threat of wildfires.
Public policies concerning fire
The governments policies are persuasion rather than enforcement, making use of television and radio campaigns. At present, the lack of information on the presence and impact of fires is the major obstacle to an effective national policy. The current initiative to develop an information system to document the occurrence of fires is a first step. At the same time, the receiving station is one of a network of sites contributing to the World Fire Web, organised by the GVM unit of the European Commissions Space Application Institute. This will enable the countrys fire activity to be documented in the regional and global perspective.
Boulvert, Y. 1986. Carte phytogéographique de la République Centrafricaine, 1:1,000,000. ORSTOM, Paris.
Cachier, H., and J. Ducret. 1991. Influence of biomass burning on equatorial African rains. Nature 352, 228-230.
Delmas, R., A. Druilhet, B. Cros, P. Durand et al. 1999. Experiment for regional sources and sinks of Oxidants (EXPRESSO): An overview. J. Geophys. Res. 104, 30,609-30,624.
Eva, H., and E.F. Lambin. 1998. Burnt area mapping in Central Africa using ATSR data. Int. J. of Remote Sensing 19, 3473-3497.
White, F. 1983. Vegetation Map of Africa. UNESCO, Paris.
Eva, H., and J.-M. Grégoire. 2001. The fire situation in Central African Republic. International Forest Fire News No. 24 (in press).