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SYMPOSIUM PHOTO INTERPRETATION, DELFT 1962 
Discussion 
Dr. Tremolieres (France) asked what has been the most important application of aerial 
photographs in Canada up till now. Answer: Probably the greatest number of photo inter 
pretation man hours in Canada are spent on forestry photo interpretation for forest inventory 
and forest management purposes. 
Prof. Snacken (Belgium) said that airphotos for forest interpretation were used in view of 
commercial output and not in terms of restitution of vegetation or conservation of soils (1951). 
Has a change in approach occured since then? Answer: While photo interpretation for forest 
inventory and forest management carried out for the major commercial organisations in 
Canada is primarily directed toward utilisation of the forest resources, it is not at all in con 
flict with these interests to expect survey for re-afforestation and/or soil conservation. While 
it is true that the main purpose is forest use, survey is required for details such as soil type, 
landform type, watershed areas, and potential forest regrowth. This type of data - and large 
areas are financed by the commercial forest operating companies - can definitely be applied 
to restitution of vegetation and soil conservation.