Ndyeshumboa, Pitio 
Most of the soils of Ngara district have either dark reddish to red or brown to 
yellowish red clayey subsoil. Top soils have a wide range of characteristics in terms of 
thickness, field impression or organic matter content and texture. 
4.METHODS: 
The study used satellite images, Geographical Information Systems (GIS) and Global 
Positioning Systems(GPS) to collect useful information and to analyse the 
environmental impact ofthe refugees influx or affected by deforestation. To measure 
with accuracy the impact of the refugees on the natural resources (deforestation) since 
their arrival. 
As a firs step a lad cover map of the region before refugees impact was established. 
This was produced using a satellite image of 1994. Two sets of (30m by 30m) were 
used to which was taken before the refugee influx (1 994) an another one of which was 
taken after the refugee influx (one of two years after). 
To complete a set of data required for analysis, an air flight was carried out to take 
some aerial photographs. Aerialphoto of 1:25000 and a satellite images (Colour TM 
composite Landsat TM 453) interpretation was done concurrently in order to assess 
the land cover changes during a period of refugees settlements. 
Afterwards, a second set of image taken two years after (1996) was compared to the 
1994 land cover map. This made possible to assess the area affected by refugees 
deforestation.. 
S.RESULTS: 
5.1 Impact in terms of area damaged by deforestation . 
The interpretation shows that deforestation area over a period of two years can be put 
in two levels of affected area; high, middle and slight. This makes possible the 
relation between these levels and cut trees. 
e high: 70% to 100% of the cut trees: 
e moderate: 30% to 70% of the cut trees. 
e slight 0% to 30% of the cut trees. 
The attribute of deforestation levels is determined by the photo interpreter. This can 
be done accurately for forest gallery and the areas where the natural vegetation is 
visible in 1994, 1995 and 1996. In burnt area it was not possible to interpret 
deforestation levels. 
52 Accuracy: 
There is high degree of accuracy for those areas which were initially covered by 
savannah. Of different factors which are believed to have been contributed to 
reduction of accuracy include; 
e the impossibility to recognise the vegetation types in areas affected by bush fires 
and therefore areas cut by refugees. 
e the deforestation caused by the local population between 87 (aerial photographs) 
and the refugee influx; 
e the deforestation caused by the local population between 94-96. 
  
International Archives of Photogrammetry and Remote Sensing. Vol. XXXIII, Part B7. Amsterdam 2000. 
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