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Fabing, Aline 
INTRODUCTION 
Nowadays several discussions about the dramatic expansion of environmental degradation guide to a solution of 
sustainable development. This concept, developed at the Rio conference (1992), has as purpose (through a dextrous 
natural resources management) the protection of the future generations and, to ensure the sustainability of natural 
resources. Furthermore, this kind of objective needs a great knowledge of ecosystem patterns, processes and 
predictability as well as information about the relationship between environmental and human factors. It needs to link 
spatial pattern and ecological processes at broad spatial and temporal scales. 
It also has to be realizes that recent past change might be identified and measured in a descriptive way while future 
change can only be modelled in a predictive manner. In this framework, this work deals with deforestation risks in a 
representative urban expansion area, which is the south Congo littoral. This area is subject to population pressures on 
the forest environment. Therefore we have chosen six training zones where different patterns have been isolated since 
1951. 
The first step consisted of the identification and the quantification of the environmental and anthropological factors that 
occur in this area. Photogrammetric and remote sensing procedure were used in combination with ground truth inquiries 
to assess the relationship between population and natural forest resources, through the establishment of physical as well 
as human factor balance. 
In the second step, the emphasis has been placed on a strategic method in order to improve environmental information 
and, to provide a reliable support for natural resources management via dynamic modelling prediction. This, by 
establishing maps predicting deforestation risks. The discussion will focus on the advantages and inconveniences of this 
procedure, on the actual human and environmental assessment and on the reliability of such aid to decision in 
environmental preservation in developing countries. 
We will first be acquainted with the area of interest and the context, followed by the presentation of the materials and 
method and, finally the results and discussion on the matter. 7 
AREA OF INTEREST AND CONTEXT 
1.1 The Congolese littoral 
  
  
  
  
  
  
  
  
  
  
  
m overs The Congolese littoral area is located at the Southwest 
Cabs A of the Republic of Congo (Figure 1). The study area 
A ; covers roughly 170x60 km , centred at longitude 
"5 A 11?45'00"' E and latitude 4?15'00" S, respectively. The 
— da Gabon delimits it on the north, the Cabinda on the 
a dan south, the Atlantic Ocean on the west and the 
N Mayombe chain on the east. 
^N M E The major features in this area are secondary littoral 
E : : forest galleries, hydromorphic forest and savannah 
ip Medora E, mosaic. Other land use present in this area for 
Atlantic STD : supporting local settlement and economic production 
Ocean wi och p : are agricultural activities for bananas, oil palm, manioc, 
N : groundnut, pineapple, and eucalyptus plantations but 
7 Pointe Moire «CETTE also fuel wood consumption (Vennetier, 1968). 
is ree UE nt 
  
  
  
  
  
  
  
Figure 1. Study area localisation 
1.2 Context 
In the Congolese littoral study area, two opposed dynamics are confronted: a forest transgression which is known for a 
long time (about 100 meters per century) versus a human expansion irregular in time and space, this in a stable climatic 
context favourable to the forest transgression (Bigot, 1996). 
  
International Archives of Photogrammetry and Remote Sensing. Vol. XXXIII, Part B7. Amsterdam 2000. 421