)Xtographs, 
, thus pre- 
yecause the 
sic natural 
1] photo- 
1 homogeneous 
rically 
nountain 
photograph 
] physio- 
nd or mire, 
numidity 
snow cover 
N COMMUNITIES 
,bare rocks 
moderate 
extreme 
glow herbs - 
high herbs 
very dry 
lichenrich 
restimossrich 
== RE Fler, 
us \mossrich 
t herbrich 
clear-cut 
mire,dry,wet 
fen,dry,wet 
inclined fen 
ultured areas 
etation. 
- 1433 - 
Much of the methodological work was designed to yield as much experience as 
possible in the interpretational problems associated with IR colour film 
(scale 1:50,000. Colour is the most important criterion used to distinguish 
the 27 different vegetational units from one another on the aerial photographs. 
Certain plant communities can be identified straightway from their characte- 
ristic colouration, e.g. the distinctive, extremly dry, dwarf-shrub heaths 
(blue) and the well-drained, low-herb meadows (rose). The identification of 
certain other plant communities may present appreciable difficulties, and 
other criterions must be used, e.g. local topography, height of the plant 
cover, its :tructure and density. The separation of meadows and willow 
thickets provides a good illustration. 
The results of the methodological studies have shown that black-and-white 
(panchromatic) film does not yield a sufficient amount of information for 
either a satisfactory delineation of vegetational boundaries, or a reliable 
classification of the vegetation. IR colour film in scale 1:50,000 proved 
to be very suitable for both of these intents; with July-August as the most 
suitable time of year. The cartographic results obtained from the interpre- 
tation of aerial photographs were checked against the results given by making 
belt transects in the field . There was a 95% agreement between the vegeta- 
tional boundaries drawn on the photographs and those found in the field. In 
comparison, black-and-white (panchromatic) film yielded only 80-85% precision. 
The vegetational classification interpretable on IR colour film had an accur- 
acy of 85%, compared to only 65% with panchromatic film, when checked in the 
field. A mapping speed of ca 10 km 
/hour was achieved by the aerial photo- 
graph interpretation method. 
PRACTICAL APPLICATION 
The methodological studies very soon led to their practical application. 
Survey maps of the vegetation, at a scale of 1:100,000 (see fig. 2), over an 
area of ca 50,000 km2 of the central mountain chain on the Swedish mountains 
will be produced. The maps are made by persons experienced in the interpret- 
ation of aerial photographs and who have a knowledge of the ecology of moun- 
tain vegetation and botanical training. Before starting on the interpretation 
of the photographs a good general knowledge of the area concerned is required, 
  
  
SENSE age 
  
  
Fig. 3 Plan for the vegetation mapping in the 
Swedish mountains.