4. Land use shifts

In The Gambia four agro-ecological zones are distinguished: the Sahelian, the Sudano-Sahelian, the Sudanian and the Guinean. The increased land degradation process during the last decades has already moved the Sahelian zone further south.

Based on the Land use changes between 1980 and 1993 monitored by Teusan (1999), the major shifts in land use indicated in table 2 and 6 are discussed below:

The total forested lands have increased due to a reversion of former agricultural land (mainly follow land) into tree and shrub savannah. Only the northern part of the country register a slight decrease

Closed and open woodland has been reducing by 3.1% or 2,700 ha per year due to forest degradation and conversion into agricultural land. The most severe degradation of woodlands occur in the central and eastern part of the country.

Suffered a slight but nevertheless alarming decreases (650 ha per year) in their total surface area. The causes are diebacks due to disturbed water exchange, conversion into rice, shrimps and fish farms and illegal exploitation. Sillah and Bojang in 1997 have however indicated good potentials for the regeneration of the mangrove forests. There is no current reliable data on mangroves, as the last inventory including this forest type was conducted in 1983. The existence of the Lowland Agricultural Development Project (LADEP) in 1997 with a 20 years life span to produce rice within the swamps will have an effect on the mangrove and riverine ecosystems.

The fallow areas have decreased by almost 50,000 ha or 4.4% due to conversion into tree and shrub savannah, agriculture with no trees or to a lesser extent into agriculture with trees. There is a loose gradient of decrease observable from the west to the east of the country. The reduction of fallow areas into forestlands has also some connection, with the rural-urban drift. The balon areas and divisional growth centres can be estimated to be growing by about 28% per year. This phenomenon deprives the rural areas of labour force, in particular the working age labour force. The remaining work labour force, mainly elderly, women and children, concentrate their farming activities only around the settlement. Those short-distanced concentrated farms are mostly not allowed to fallow more than a year or two.

The new forest legislation considers fallow land as forests if the number of trees per hectare with diameter at breast high of twenty centimetres or more exceed one hundred. Based on this definition, agricultural lands reverted to forests fall under the provisions of the Forest Bill and Forest Regulations of 1998 and thus become forest reserves. This means that statutory law replaces customary tenure rights, which may result to land use conflicts. The establishment of private natural forest would probably be the best compromise to avoid conflicts and to maintain an adequate forest cover on such lands.

The class remained relatively unchanged. While a portion was converted into agriculture with no trees, almost the same proportion was added from fallow areas and woodland. There is a concentration of agriculture with trees in the West part of the country whereas the more up-river area is more agricultural without trees.

The class increased in the average by 1.3% or 1,140 ha per year. Here, the soil is constantly exposed and under stress. Poor soils and poor production yield, even with high input of chemical fertiliser is a widespread characteristic.

The western parts of the country have the highest percentage of land classified "others" with increasing tendency, whereas up-river this category decreases due to migration patterns both internal and external.

Table 6: Land use change in The Gambia (1980-1993)

Sources: Teusan, 1999

Based on the findings the following conclusions can be drawn:

~the major reserves of arable land are be found in the Western and Northern part of the country mainly in former fallow lands. The rest of the arable lands can only be found under forest cover. For this reason, remaining woodlands covering better sites are always attractive as agricultural land with the highest tendency in the west and central part of the country.

~in regions that have marginal soils (most parts of the eastern part of the country) seems to have forested lands being already pushed to non-arable sites and fallow lands on marginal sites were recovered back to tree and shrub savannah;

~the increased demand on wood products in urban and semi-urban areas confirmed the highest decreases of woodlands in these areas compared to the others. This has a direct connection with the population growth of those areas and the socio-economic developments.

~the steady diminution of trees on farmlands particularly in the east, leads to increased wind and water erosion and negatively affects the soil water and nutrition cycles;

~the decrease of fallow lands and, thus, shorter fallow periods is wide spread, but more prominent the northern part of the country; and

~the change in tree species composition to more fire resistant species is steadily pushing the natural vegetation woodland species to almost local extinction.