)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.