Full text: XIXth congress (Part B7,1)

  
Fabing, Aline 
  
1.6 General description 
The region is actually relatively stable in terms of present deforestation, it is more suitable to talk about forest 
degradation (usually transformed in bushes). Land-use change particularly over the last 20-30 years has been largely 
responsible for the forest extent and conditions of it actual patterns. 
In our area, gallery forests are accessible and are subject to strong pressure, on the otherhand there are hydrological 
barriers (Kouilou and Loeme rivers) where forest is stable or transgress. The annual rate of deforestation is estimated at 
0.6 percent for Central Africa (FAO, 1997). 
In our area, this rate depends on the location, the speed of forest cover change is variable. In the north, above the 
Kouilou river the forest transgression is about 0.03 % per year, 0.020 % per year at the east of the Loeme river. Close to 
Pointe-Noire, gallery forest is transformed in agricultural zones and disappears, it looses 0.023 % per year since 1951 
while under intensive exploitation. On the other hand, the agricultural areas gained about 0.08 % per year. 
1.6.1 Forest evolution since 1950, a contrasted assessment: Urbanisation and land desertification ; 
The main observation and measure we could make was the imbalance between rural and urban areas, the first became a 
human desert and the other cumulated all human flows. This allows us to notice that deforestation and forest 
degradation are concentrated along the road network since the access to the forest is facilitated by the tracks opened by 
logging companies. But as soon as we go into the land, we can observe forest stagnation but also transgression without 
any human interference (fire bush). Likewise, if population pressure is not important and/or far away from Pointe- 
Noire, forest tracks can close in ten years of time. Anyway, the primary cause being the demand of food supplies for the 
Pointe-Noire City. 
1.6.2 Structural balance: which interrelations? 
The deforestation and land degradation are a combination of factors, the process of forest colonisation is the following: 
logging companies, exploiting government concession open the forest with creating primary and secondary roads. With 
the increase of food products (manioc, bananas etc.) requirement in the city, people settle along the roads and initiate 
the trade of these products, which can generate a colonisation within the primary forest. With food products is also 
associated fuel wood production since urban people conserve the rural usage. This last factor is determinant on the 
amplitude and velocity of forest degradation. One new factor is growing up: civil war, which has driven several 
hundreds of thousands of people into the Pointe-Noire area, where they contribute to the pressure on the forest (1997) in 
order to subsist and to earn money, fuel wood production is their first activity. 
1.6.3 Particular case 
The south Conkouati’s particular case: an Asian logging company has acquired a concession in 1992 from the 
Congolese government. These concessions are nearby harbour facilities, which reduces considerably the transportation 
costs. The concession can then log less expensive species, since transportation costs represent up to 50% of the total 
timber cost. It means that there is danger of intensive logging in this location, and possibility of clear-cutting (TREES, 
1997). Actually and with the civil war this company has disappeared while there is no trace of clear-cutting on the radar 
data but the inquiries on the ground confirm that fact. 
1.7 Discussion 
1.7.1 The main factors 
1.7.1.1 Growth of human pressure... risks... 
Population growth is probably the main factor of deforestation, but the economic conditions of the region are 
considerably degraded since 15 years, what has led to a comeback of urban inhabitants to the rural areas. Natural 
resource exploitation is often the only way for rural and also urban people to ensure their subsistence, since other 
economic activities do not exist. A distinction of urban and rural people is necessary in order to describe the 
deforestation process. An increase of rural population leads to a reduction of the fallow duration and, in the midterm, to 
land degradation. It often takes place in the secondary forest but when the population pressure becomes stronger, 
primary forest can be attacked. An urban population growth (natural growth and migrations) increases the food demand 
and creates an economic market which initially is a subsistence system: in this way the impact on deforestation depends 
on the accessibility, and therefore on the road network quality. 
  
424 International Archives of Photogrammetry and Remote Sensing. Vol. XXXIII, Part B7. Amsterdam 2000.
	        
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