4 JOURNAL OF FORESTRY 



readers that they must not be too skeptical about the results which can 

 be obtained as I have seen many preconceived ideas completely changed 

 after short flights over forest areas. Until one has flown he can have 

 absolutely no idea of how much can be seen from the air, especially 

 after a few flights. It is exactly like having a colored relief map spread 

 out below one for study. 



Owing to a strike of lens makers it was impossible to procure an 

 aerial camera until the season was almost over but many trials were 

 made with various hand cameras and some good oblique pictures 

 obtained. An aerial plate camera of the type used in training cadets, 

 using 4 by 5 plates, hand operated, was tried and good pictures obtained. 

 It was found very hard to get these to overlap and the capacity of the 

 camera was small, as was the amount of country covered by one 

 exposure. Finally a Kl Eastman Aerial Camera was obtained, operated 

 by a wind motor and taking 100 pictures 7 by 8^ automatically and 

 continuously. Nearly four hundred of these were taken over all kinds 

 of country with most satisfactory results. This camera was found 

 most satisfactory, easily regulated as to speed, very simple to load 

 and operate and with very little to get out of order. It is made with 

 lenses and cones which can be interchanged in a moment; so that, if 

 wanted, pictures can be taken at a good altitude covering a large amount 

 of territory, which can be used as controls, the lens can then be 

 changed and the details filled in from a lower altitude. 



Pictures were taken from 1,000 to 5,200 feet altitude and the best 

 results for all round work over forests were obtained at about 5,000 

 feet which gives a scale of approximately 400 feet to one inch. No 

 difficulty was found in keeping the elevation of the plane sufficiently 

 constant to avoid changes in the scale and the pictures could readily 

 be matched up and checked well with the maps where the latter were 

 available. There is almost always some land feature which shows in 

 a strip of pictures the length of which is known or can be measured, 

 by which to check the scale. 



As to what can be read from the photographs. We are still in the 

 very infancy of this work, but it may be said without question that 

 for mapping purposes alone, the photographs are far superior both in 

 detail and accuracy to ground work. The speed of operation is also far 

 superior. On the ground, in this country, with a party of ten men 

 using the plane table, 50 square miles a month is the average area 

 covered, as against 200 square miles per day with good photographic 

 weather, which can and has been done easily. 



