ALPMON FINAL REPORT - ARC systems research

Contract ENV4-CT96-0359 ALPMON
Through producing virtual landscape photographs and 'fly throughs' remote sensing data can be used
for publicity purposes. They provide a very good impression of the landscape and, together with a
digital elevation model, the morphology.
However, the remote sensing data can also be used very well as background for hiking maps and
other thematic maps. Satellite images increase the attractiveness of these maps and, with a suitable
print quality, can at the same time represent the various structures of the landscape. For the Forest
Administration analogue maps were printed which show the fusion image as background. As additional
information, the streets, trails and the place names were added. A survey map of scale 1:50 000 and a
more detailed map of scale 1:25 000 have been made.
2.3.1.3.3 Task: land cover
A description of the present land cover was required by both customers: the Tourist and the Forest
Administration at Tarvisio.
The satellite image classification has already been described in detail (reports to work packages 9 and
10). The customers were satisfied by the results of the classification. Though there have been some
lacks: the shaded areas could not be classified; sealed surface could not be separated from rock.
However the classification results show a good view of the present situation in the test site.
2.3.1.3.4 Task: Monitoring of forest /open land - example: alpine pastures
For landscape related tourism, open areas are very important. They liven up the forest areas, they give
the possibility to rest on blooming meadows and last but not least they give the chance to admire the
panorama. However, natural open areas only occur in high areas (alpine meadows). Below the timber
line, nearly all open areas were made through agricultural use and therefore build a man-made
landscape. The difficult situation of agriculture in the Alps resulted again and again in areas that are
given up. The result of giving up these areas is the recovery of forest.
In order to see, whether modifications occurred in the last decades, the fusion image of 1992 is
compared with black and white aerial photos of 1954. In this way a period of four decades could be
investigated. As an example the evolution of the alpine pastures were chosen. This example interested
all of our customers: the Forest Administration at Tarvisio (concerning the increase of forest) and the
Tourism Administration (concerning the loss of open land). In addition the Comunità Montana at
Pontebba was very much interested in the changes of the alpine pastures.
Three different classes were measured: pasture, succession and forest. The succession and forest
areas have to have at least 0.1 hectare. Areas with 10 to 30% of tree stocking were defined as
succession. Forest is defined as area which are at least 30% covered by trees. Within succession and
forest there areas without stocking were delineated if this area has at least a size of 0.1 hectare.
Result:
In fact there occurred a clear landscape modification in the last 40 years. Almost on all alpine pastures,
a clear increase of forest could be observed. An increase of pasture did nearly not occur. Only on
single plots there is an expansion of the pasture. A good example is the alpine pasture "Goriane". The
increase of forest is clearly to be seen. In the northern part there is a slight increase of the pasture to
the east and west: an exception as mentioned before.
In total the pasture has lost approximately 170 hectares. That corresponds to 35.5% of the pasture
area of 1954. The entire area of successions only increased insignificantly. It is to be found on about
65 hectares 1992 and on 62 hectares in 1954. That means the decrease of the pasture area has
almost gone completely for the benefit of the forest.
The ortho-rectification of the aerial photos would have been more precise if the original photos could
have been used. Using a specific scanner would minimise the distortion. However, it is considerably
more economic to use normal scanners. For the aim 'monitoring of landscape modifications', this lowcost
method is sufficient since no highly precise measurements are necessary. The problem of the
missing camera calibration and the lack of older topographical maps for getting control points has been
considerably more seriously. Due to the inaccuracies, clear differences have to be proved in order to
be able to talk about landscape modification. Therefore, all information was only given in hectares.
More precise statements are not possible on the basis of the available data. However, the landscape
modifications are engraving in the last 40 years. This could be clearly proved in spite of the not optimal
data basis.
JR, RSDE, ALU, LMU, Seibersdorf, WSL 29