COMMISSION VII: INTERPR 
portant source of variation, that crown clo- 
sure and height are the most useful variables, 
that for photo-cruising photographs secured 
at a scale of 1:14,400 with a 12-inch Ross 
camera are preferable to those at 1:15,600 
or 28,800 taken with a 6-inch Wild RC-8 and 
that use of positive transparencies did not im- 
prove photo-mensuration significantly. 
Because of the wide variation between re- 
sults of interpreters measuring the same plots 
and because of differences between stands, it 
was concluded that best results will come 
from localizing photo-volume tables or equa- 
tions through use of appropriate statistical 
techniques. 
FINLAND 
Forest conditions in this country are very 
similar to Sweden and therefore the applica- 
tion of aerial photographs to forestry has de- 
veloped along quite similar lines. For this 
reason the use of aerial photographs in Fin- 
land is quite widespread at the present time, 
and according to the information obtained, 
forest inventory work could be speeded up by 
20 to 40% in South Finland and by 50% or 
more in North Finland compared to pure ter- 
restrial surveys. 
The scale of the photographs used for this 
purpose is normally 1:20,000 in the South 
and 1:30,000 or 1:40,000 in the North. Every 
vear an area of 1500-2000 sq. km is photo- 
graphed for special forestry purposes, In addi- 
tion, other photographs made primarily for 
the topographic survey are also used to a 
large extent in forestry. In North Finland 
photographs for forestry are made by a wide- 
angle Topogon camera and also by Wild 
RC-8/9x9 inch. Normally panchromatic 
film is used. Special tests are made in some 
selected areas in North and South Finland 
with Kodak Ektachrome Aerographic High 
Contrast Film with an RC-8/9 X9 inch cam- 
era in combination with HF3 and HF4 filters 
on scales varying between 1:5000 and 
1:30,000. The results of these tests have not 
become available so far. 
Aerial photographs are mainly used in the 
State Forest Service. It was possible to state 
that in the North, 9095 of the data could be 
obtained by photo interpretation methods, 
whereas in South Finland the proportion was 
only 25-5095 due to a greater variety in 
stand composition in this part of the country. 
Nevertheless the introduction of aerial pho 
tography to Finnish forestry has resulted in a 
complete change in conventional forest in 
ETATION OF VEGETATION 
ventory, which in former times was based 
solely on terrestrial methods. 
FRANCE 
As already reported the application of 
aerial photographs in forestry in this country 
is still in its early stages. Nevertheless interest 
for this new technique is growing so that as a 
result of our questionnaire some interesting 
information was obtained. 
For example some practical results in aerial 
photo interpretation can be recorded from 
northern France (Rouen region). The aerial 
photographs available were made by the IGN 
on a scale of 1:25,000 with a 125 mm camera. 
Photographs were used for a twofold pur- 
pose: first to obtain in a short time a better 
and overall estimate of the area of productive 
forest, the area which had been recently cut, 
the local distribution of the cuttings and 
their dimensions. It was stated that the ap- 
plication of aerial photographs in this con- 
nection achived a saving in time of 50-609. 
In addition, in the same region a special 
survey was made of the occurrence of Nor- 
mandian Fir. This forest inventory project 
was started at the request of the French pulp 
industry. Normandian Fir occurs in this part 
of northern France only in small isolated 
wooded areas so that the use of aerial photo- 
graphs seemed advisable. By an initial super- 
ficial study of the photographs it proved pos- 
sible to differentiate the fir tree from the pines. 
To make separations from occasional spruce a 
verification on the spot was necessary. After 
the delineation of types on the photographs, 
a determination of the total area occupied by 
fir was obtained by dot counting on the 
photographs. Types were subdivided accord- 
ing to density classes. The total area occupied 
by fir stands in this part of France proved to 
be 6,000 ha, distributed over more than 1,000 
separate forest tracts. The whole survey took 
about 130 man hours; without aerial photo- 
graphs it would have taken much longer to 
obtain comparable results. Based on this in- 
formation an estimation of the timber volume 
by terrestrial sample plots is planned. 
Other reports of the application of aerial 
photographs in forestry have been recorded 
from the French Alpine regions. Here aerial 
photographs were successfully used to deter- 
mine avalanche routes and further to deline- 
ate main forest types and site conditions in 
mountainous regions. A further report dealt 
with the Mediterranean coast. To obtain 
better timber estimates of the Cork Oak for- 
ests aerial photographs were used. Results ob-