REPORT OF COMMISSION VII 
G VI1-33 
Photo interpretation does not furnish knowledge about the forests in France 
—these have been known for a long time—but interpretation does present two 
very appreciable advantages in intensive forestry. On one hand it permits sim 
plifying and specifying the location of observations. On the other hand it per 
mits generalizations to a certain degree. The organizations for Colonial Forces 
working in black Africa have begun to use photo interpretation in prospecting 
the Colonial forests. 
Air photographic interpretation is being employed in forest inventories 
throughout Canada to minimize the labor of field sampling. 
Forest sites are also being interpreted and a system has been developed 
whereby land form, land form position, and vegetation are employed to indi 
cate soil moisture, parent soil material, and great soil group. 
In Norway great studies have been made in use of aerial photos. Aerial pho 
tos are used for preparing management plans, for analysis of soil, and analysis of 
vegetation cover. Also special surveys in logging, reforestation, survey bound 
aries, and land use surveys have been developed. 
In 1955 the Airborne Mapping Ltd. of Sweden photographed about 2,000,000 
hectares of forest. These photographs will be used for the plotting of special for 
estry maps of the scale of 1:10,000 and 1:20,000. 
New approaches are developed to inventorying timberlands with the aid of 
vertical aerial photographs. New survey methods are applied in New York State 
to a sample forest classification of northern hardwood type growing on land of 
medium site quality. The importance of field reconnaissance is emphasized. 
Procedures are presented for collecting and analyzing data from forest plots, 
including the method of constructing tree volume tables based on crown sizes. 
Three methods of estimating timber volumes were used: (1) plot cruise on 
photos, (2) mean crown diameter, and (3) tree crown count. Photo volume tables 
are developed for use in estimating timber volumes for twenty four forest type 
and site classifications. 
PHOTO INTERPRETATION IN LAND USE MOVES AHEAD 
France has found that interpretation facilitates the identification of parcels 
of land and the classification of soils in order to work them. 
The Prairie Farm Rehabilitation Administration of the Department of 
Agriculture, Canada, has found that, with a knowledge of geological processes 
and soil peculiarities, soil conditions may be interpreted from air photographs, 
and that preliminary irrigation and water development surveys can accordingly 
be facilitated. 
In the United States photo interpretation was used to obtain land use data by 
selected soil groups for agricultural and urban land. These cover classes included 
small grain, hay, pasture, etc. The soil-cover information was used for hydro- 
logic analysis of the basin and for program planning. Photo interpretation was 
used to obtain land use data by flood frequency zones on a large river flood plain, 
for use in economic appraisal of the flood control program. Data were obtained 
for natural conditions and the modified conditions prevailing after construction 
of flood control dams. Information of flood plain land use is difficult to obtain 
except by field mapping because most land use information is inventoried by 
political subdivisions. 
AERIAL PHOTOS EXPEDITE FOREST LOGGING OPERATIONS 
Since 1949, the Swedish Pulp Company (Svenska Cellulosa AB) has been 
using photographs instead of drawn forest maps for about 8,000 km. 2 It now