WORKING GROUP 4 
FRANGIS 
209 
The next development to which I would like to refer is that of visual aerial 
surveys to supplement photo interpretation and the ground survey work 
required for forest and soil sampling. Visual aerial surveys can be particularly 
valuable where colour changes are relatively slight and limited to flowering, 
flushing or fruiting seasons of short duration. A visual aerial survey at such a 
time, when carried out by an experienced observer, preferably having with 
him copies of the aerial photographs of the area, can provide much supple 
mentary information in a fraction of the time and at very slight cost compared 
with the work which would have been necessary on the ground. A further 
refinement of this is to use a helicopter for the work so that the ground sam 
pling to check aerial observations can be made at frequent intervals. This 
work is not as expensive as it seems at first sight, and results in considerably 
increased efficiency on the part of the field crews and a considerably enhanced 
output of work in a given time. Delegates present are recommended to con 
sider the work carried out by the British Columbia Forest Survey Division 
who have published admirable reports on this type of work. Colleagues in 
British Columbia have told me that the increased adoption of helicopters for 
field sampling in the province has cut their costs by 75 percent. The only 
limitation is the relatively short field season and shortage of trained observers. 
Yet another development of note is the use of electronic computers for data 
processing and for analyzing the results of field surveys. This work, at present 
confined to a few developed countries, has a great potential for assisting the 
developing countries, since the computer programmes, once completed, require 
only raw information. Many of the developing countries are capable of col 
lecting this information themselves, and require only the short term advice of 
a specialist in electronic computers to draw up the requisite programme. 
Then data can be processed extremely rapidly, subjected to confidence tests 
for its degree of precision, and finally presented in a suitable form (printed 
schedules) for determining the practical application of the results. 
These comments, which only touch on some of the more recent develop 
ments in this field, nevertheless indicate where we are moving today. In many 
ways the developing countries have a magnificent opportunity to make the 
fullest use of these modern techniques to carry out work which the more 
developed countries, to some extent hidebound by tradition, are sometimes 
reluctant to undertake themselves. Some of the developing countries have 
already grasped the value of these modern techniques. One such country 
where I have served has already moved over to the use of electronic distance 
measuring instruments, electronic printers for making better aerial photo 
graphs, doppler navigation for its air survey unit, modern photogrammetric 
machines, visual aerial surveys and field sampling by helicopter, and local staff 
trained in the use of aerial survey techniques. As a result, they have been able 
to carry out surveys of vast areas which could not have been contemplated 
ten years ago. These developments continue, and if, in my talk today, some 
of you have been stimulated into thinking along the same lines in your own 
territories, then I hope you will take this opportunity to follow the matter up