Rit Landbúnaðardeildar : A-flokkur - 01.10.1967, Blaðsíða 39

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The program has been supported financially by the Icelandic Science
Fund, the Land Reclamation Fund of Iceland and by the Scientific
Affairs Division of NATO. It has also benefitted greatly by the use of
base maps kindly supplied by the U.S. Map Service.
The main purpose of this work is to determine the carrying capacity
of the highlands and to map areas of soil erosion which is an extensive
problem in Iceland.
The program at present falls into four main categories:
1. Classification and mapping of the vegetation with the aid of aerial
photographs.
2. Measurements of botanical composition and annual production of
plant associations.
3. Studies on the plant preference of sheep.
4. Studies on the chemical content and digestibility of range plants.
To this date the vegetation of about half of the total area of Iceland
has been mapped. The first six sheets of the vegetation map were
published in 1966 in the scale 1:40.000. The program provides for an
annual publication of ten sheets.
The paper describes the vegetation and the main characteristics of the
plant communities of four adjacent highland commons in South Iceland
i.e. the commons of Hrunamanna, Flóa, Skeiða and Gnúpverja counties.
The paper also includes brief discussions on the geological and
morphological features of the area studied (with map) and its estimated
annual precipitation which yet is the best known climatological feature
of the highlands. However, as they are not inhabited actual knowledge
about their climate is very limited.
The total area studied covers about 2200 km" most of which are between
300—800 m above sea level. Mountain range as high as 1400 m is, however,
to be found in the northern part of the area.
The main bedrock is basalt while there are local occurrences of rhyolite
and palagonite.
Annual precipitation is estimated to vary between 600 and 2000 mm of
which about 20 per cent are estimated to occur during the short growing
season, June-August.
Vegetation covers only about 30 per cent of the area. However, there
is evidence indicating that the cover of vegetation in the past was
far more extensive than it is now. In the past centuries cold climatic
spells, volcanic eruptions and local overgrazing have caused a rapid
deterioration of vegetation and subsequent soil erosion, which seems still
to exceed that regained annually by natural regeneration.
Continuous vegetation covers a fairly well defined area, with an upper
boundary near the 600 meter contour line. The vegetation is classified