COMMISSION VII: INTERPRETATION OF VEGETATION 
surveyed. Several forest types were distin- 
guished, in particular the secondary forest, 
savannah, low forests; a subdivision into sev- 
eral volume classes was made. The sampling 
was done in units of 1 ha each along transects 
projected perpendicular to the topographic 
lines. Within 5m on both sides of the tran- 
sects all trees with 25 cm d.b.h. or above were 
measured. The transects had a standard 
length of 10 km, but varied from 6 to 27 km; 
normally the third, sixth and tenth km were 
measured in order to obtain sampling units of 
1 ha each. The sampling intensity varied 
from 0.03 to 0.006%. In the last region sur- 
veyed so far (between the rivers Caete and 
Maracacume) a soil survey was carried out 
and a soils map prepared for the first time; 
also a geological description of the area is in- 
cluded in the report on this region. 
The forest inventory work was extended 
also beyond the Amazon and a survey of the 
Parana pine stands started. À preliminary 
volume table for Araucaria angustifolia has 
been prepared and published for the State of 
Santa Catarina. 
CAMBODIA, VIETNAM AND LAOS 
The major part of these countries has been 
covered by aerial photographs. This coverage 
was originally secured for cartographic pur- 
poses, but has also proved valuable for study- 
ing the local vegetation. Already at the begin- 
ning of this decade aerial photographs were 
made by I.G.N. These photographs were 
made on a scale of 1:40,000. The area covered 
included the whole of Vietnam, 2 of Cam- 
bodia and a part of Laos. Photo size was 13 by 
18 cm and panchromatic film was used in 
combination with a yellow filter. Photo- 
graphic quality in general was good. Prints 
were made on glossy paper. The same flying 
agency also secured some local photograph; 
on larger scales (1:5000 to 1:20,000) for 
military purposes. Also some incidental Tri- 
metrogon photography was made. 
In addition to this survey an American 
agency very recently started aerial survey in 
these countries. This covers the whole of 
Cambodia, the southern part of Vietnam and 
[Laos including a part of Thailand. Photo- 
graphic material was available at the end of 
1959. Photographs were also made on a scale 
of 1:40,000. Photo size was 9X9” on pan- 
chromatic film with yellow filter. Prints were 
made in semi-matt. Special large-scale pho- 
tography (scale 1:10,000) was obtained in the 
south-eastern part of Cambodia. This was 
carried out particularly for forest inventory 
purposes but is yet available. 
Based on the interpretation of the French 
photographs, vegetation maps were prepared 
on a scale of 1:400,000. Such maps were made 
for South Vietnam covering an area of 
170,000 sq. km and for eastern Cambodia 
(65,000 sq. km). No information was given on 
what principles this interpretation work was 
based and to what extent vegetation types 
could be differentiated on the photographs. 
Besides on vegetation, these maps will also 
give indications on relief, rainfall, tempera- 
ture, geology, soils, land utilization and cli- 
mate. In close cooperation with the type- 
mapping work, terrestrial sample plots were 
measured in various forest types in order to 
get more detailed information about timber 
volume and growth data. 
The recent American photographs will also 
be used for constructing vegetation maps; 
however, it seems that more detailed informa- 
tion regarding the composition of the vegeta- 
tion will be required as the vegetation maps 
are to be made on a scale of 1:40,000. This 
mapping project will be started this year. For 
the time being, the work will be carried out 
for Cambodia only. Perhaps the other coun- 
tries in Indo-China will be worked out in the 
future. Besides this type-mapping work it is 
proposed to work on the large-scale photo- 
graphs in order to obtain more information on 
the possibility of measuring crown diameters 
and estimating crown densities. [Interesting 
results may be expected from the whole 
scheme in the future. 
BELGIAN CONGO 
Up to now 80% of the whole territory has 
been photographed from the air. The scale of 
photography varies between 1:30,000 and 
1:49,000. Camera types used are Wild L4C1, 
RC5-L4C2 and RC5a-L4C3 Aviogon. Infra- 
red film 1s used. This aerial photography is 
carried out principally for compiling topo- 
graphical maps; this is performed by the 
[.G.C.B., in Leopoldville. But in addition 
this photographic material provides an excel- 
lent opportunity for a more detailed study of 
the local vegetation. In this connection it is 
fortunate that the infrared photographs give 
much greater differentiation within the tropi- 
cal rain forest than the ordinary panchro- 
matic film. So far the following results can be 
recorded: 
Forest inventory: A forest inventory project 
was started for obtaining a better estimate of 
the timber volume of ‘limba’ (Terminalia 
superba). This species occurs in the tropical 
rain forest, where it grows mixed with other 
species. Limba occurs particularly in the 
most western part of the Congo over a total 
area of 30,000 sq. km, which was for the most 
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