as field checks,
sting maps.
; in an Inter-
1 20 to 15 times.
raced onto trans-
> number. The
survey for each
| survey, any
lata contained
se map with the
indicate the
najority of cases
aa into its natural
| factors, viz.
r nutrient status.
plant community
the former exceeds
sed to designate
and boulder-strewn
y vegetation maps
age which can be
such an extent
esent a complex
S.
great problem for
and when making
are virtually
h concentrated to
a study of the
each of which is
s thus expected
parate map sheets
L
| interpretation
hern and central
lassification
subsequently
; (fig. 3). The
| vegetation cover
omic factors and
is suitable both
ind for more de-
)). An assessment
viz. black-and-
- 1435 -
FOREST
10 Mixed forest : 4 VEGETATION OF OPEN GROUND (HEATHS AND GRASSLANDS)
1l. Coniferous forest 41 Dwarf-shrub and grassy heaths
111 Spruce forest 411 Calluna heath
112 Pine forest 412 Empetrum heath
113 Other types 213 Other dwarf-shrub heaths
12 Deciduous forest (demanding species) 414 Acidic, sandy grass-heath
121 Oak forest 415 Wet heath
122 Ash forest 42 Dry grasslands
123 Other types 421 Dry grasslands and hillslopes, Of ordinary type
124 Beach forest 422 Steppe-like grassland
13 Deciduous forest (indifferent species) 423 Basic, sandy grass-heath
131 Birch forest (Betula pubescens complex) 43 Damp grassland and other types
132 Grey alder forest (ATnus incana) 431 Damp grassland
133 Hazel 44 Wet grassland
134 Other types 441 Wet grassland rich in tall herbs
-
4 Deciduous forest (wet types)
141 Black alder forest (Alnus glutinosa)
142 Birch forest (Betuld verrucosa complex)
15 Clear-felled areas
442 Mixed grasses and low-growing sedges
443 Wet calcareous grassland
444 Salt~ and freshwater marches
45 Landscape of glacier-smoothed rock
451 Bare rock
452 Calluna-heath covering slabs
453 Heath-covered rocks and boulder$
454 Maritime rock vegetation
OPEN FOREST (PARKLANDS)
20 Mixed coniferous and deciduou$ species
21 Coniferous species dominant
211 Spruce predominant 46 Open raised bogs
212 Pine predominant 47 Wooded raised bogs
22 Warmth demanding deciduous species 48 Fen
221 Dak predominant 481 Poor fen
222 Other species 482 Rich fen
23 Other types of open forest 49 Reedbeds (Phragmites)
231 Birches
232 Rowan 5
233 Grey alder
URBAN ENVIRONMENTS AND CULTIVATED LAND
234 Other deciduous species J
Arable land and hayfields
52 Built-over land
53 Orchards
SCRUBLAND 54 Other types of landscape under urban influence
31 guniper scrub
32 Willow thickets
33 Maritime deciduous scrub
34 Other types of scrubland
341 Deciduous scrub
342 Thickets of thorny species
Fig. 3 Classification scheme for the vegetation in south- and central
Swedish terrain, modified for aerial photo interpretation.
white (panchromatic) film on a scale of 1:30,000 and IR colour film on scales
of 1:50,000, 1:30,000 and 1:20,000. In each case the degree of precision given
by each film type and scale has been assessed in relation to the vegetational
boundaries, the vegetational classification and the amount of attainable de-
tail.
The methods have been tried out in seven different test areas, altogether
covering an area somewhat in excess of 100 km and distributed throughout
southern and central Sweden. Each of the various vegetational units distinguish-
ed on the aerial photographs was located in the field and classified on the
spot.
The results of the methodlogical studies indicate that the photographs obtained
from panchromatic film yield a satisfactory degree of precision as regards draw-
ing the boundaries between different plant communities. The boundaries in general
are well-defined and usually related to human influence. The possibility of inter-
preting from these aerial photographs, without field-checks of the classification
decisions made is however very limited. The classifications were only correct
in 60% of all cases. Use of panchromatic film for the production of vegetation
maps therefore demands a great deal of fieldwork and, as far as
possible, use of a rather simplified classification scheme. By mapping from
