167 
Forest present only in 1983 
Forest present only in 1954 
Forest present both in 1954 and in 1983 
Non forest area 
4. RESULTS 
A new automatic forest area recognition technique has 
been deveioped and tested. This procedure has proved 
to be effective for the automatic detection of the forest 
coverage using aerial photographs. This technique can 
be used to estimate the extension of the forest changes 
overtime. 
A skilled operator is able to perform the whole operation 
in a very short time, especially compared to traditional 
techniques. The procedure consists in an image 
classification carried out for each image followed by a 
supervised homogenization which has permitted to 
accurately detect the real forest coverage per each 
image. 
There is a well known growth trend but its extension 
has never been evaluated exactly The results can be 
used as an input for further analysis such as 
economical, sociological and biological studies. These 
studies have been carried out but they are not reported 
here. Nevertheless, it is very interesting to mention that 
an exact correspondence between the forest area 
coverage increase and the population decrease has 
been observed. 
A precise knowledge of the forest coverage evolution is 
very precious to enhance forest and landscape 
management criteria. It can also be combined with 
demographic information to better explain landscape 
change. 
Fig 14 Forestarea change 1954-1983.