METHODOLOGICAL STUDIES ON THE MAPPING OF MOUNTAIN VEGETATION
The mountain vegetation is the easiest to study using aerial photographs,
since the forest cover is both sparser and covers far less area, thus pre-
senting far less hindrance in photographic interpretation, and because the
lack of human influence on the vegetation, thus allowing the basic natural
environmental factors to exert their full ecological effect.
There are two main problems in making vegetation maps from aerial photo-
graphs, firstly, the difficulty of drawing up boundaries between homogeneous
vegetational units; secondly, ensuring that such units are botanically
correct.
The vegetational classification scheme adapted for mapping the mountain
plant communities has been specially adapted for use in aerial' photograph
interpretation. It is based on phytosocialogical, ecological and physio-
gnomic criteria. The vegetation is classified as heath, grassland or mire,
each group being subdivided in relation to nutrient status and humidity
(fig. 1). In the lowalpine region the depth and duration of the snow cover
plays a large part in determining vegetational distribution.
MOUNTAIN VEGETATION REGIONS MAPPED VEGETATION COMMUNITIES
high alpine boulders,bare rocks
menn" 1600. x Tm TErass-dom Heath 7
moderate
snowbeds
extreme
m uendouc $ Ov herbe,
high herbs
very dry
dry
heaths damp
s wipe t ann
lichenrich
birch forestimossrich
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i coniferous \ mossrich
Coniferous fores A \ À A À À forest herbrich
Alpine middle alpine
region
low alpine
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Birch forest-
region
region clear-cut
A amy mire mire,dry,wet
t. [miens
inclined fen
cultured areas
Fig. | Classification scheme for the swedish mountain vegetation.
The figure also shows the different alpine regions.
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