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Land-forms map 
Through the geomorphologic photograms interpretation and the 
use of parallax bar, it was possible to draw-up a map dividing the 
territory into homogeneous zones, according to gradients and type 
and shape of the reliefs. The slope gradients were divided into 
four classes: from 0% to 3%, from 3% to 8%, from 8% to 15% and 
gradients higher than 15%. 
The slopes' shapes were thus divided: 
- lands subject to recurrent overflows, comprising the lands 
between riversides (swollen riverbeds) and the lower alluvial 
terraces in general; 
- lands subject to discontinuous floods, comprising the higher 
alluvial terrace of the two major watercourses and part of col- 
luvial zones; 
- little-closed basins, filled with alluvial and colluvial mate- 
rials, present also in zones having an undulating morphology 
and characterized by a strong hydromorphism; 
- plain and gently undulating lands representing a narrow connec 
tion strip between the low zones previously described and the 
hilly undulating lands; 
- hilly undulating lands; 
- hilly undulating lands with sharp breaks of slope. 
c) Land-use map 
Examined country is mostly characterized by natural lands, 
whose vegetation can be divided as follows: Primary Forest, Secon 
dary Forest, Swamp Forest, Swamp grassland, Secondary Growth and 
cultivations. A short description of every land-use is given be- 
low. 
- Primary Forest: evergreen rain-forest characterized by a vege- 
tation placed on 3 layers: the first with trees having an avera 
ge height comprised between 35250 mt. and a discontinuous course; 
the second with plants 25-35 mt. high and a good regularity; the 
third, which is much lower and scantily visible from upwards, is 
formed by very young species. 
In general they show a medium-grey tone and a very coarse texture. 
The foliage of each plant is easily visible. 
- Secondary Forest: this forest forms when the original vegetation 
has been removed; it does not present a precise bedding or at 
the most it is only just visible. It shows a pale-grey tone, the 
texture is much less coarse than previous one described and the 
foliage is hardly visible. 
  
- Swamp Forest: this type of forest is typical of lands more or 
less frequently subject to overflows. The trees usually belong 
to the same species of those of Primary Forest, from which they 
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