THE USE OF ARICRAFT IN FORESTRY 



327 



It was wonderful, in flying over a wooded country, to 

 see how easily the boundaries of the various timber types 

 could be traced and by taking a map into the air, the 

 various types, the approximate size and density of the 

 timber could be esaily sketched on it, and that, too, much 

 more accurately than from a ground reconnoissance. One 

 afternoon, flying over a tract of fifty square miles which 

 had been carefully mapped a few years before, I found a 

 small lake which had not been located by the field party, 

 and although I had often been over the tract on foot, I 

 brought back more information in the hour I was over 

 the tract than I had previously gathered. In flying over 

 a tract which we contemplated purchasing, we were able 



bi-weekly aerial photographs of the log drives so that it 

 can see at once what progress has been made and 

 whether the rivers have been swept clean. By noting the 

 points where the logs jam and stick it will be possible to 

 make plans for the removal of obstructions, the building 

 of piers and other river improvements. 



Photographs are taken at the speed of about sixty miles 

 an hour, which means about one hundred pictures in 

 that time covering forty-five square miles about as much 

 country mapped in one hour as a crew of men will do in a 

 month and with much more detail and accuracy and giving 

 at the same time, directly from the picture, the areas of 

 lakes, of burns, of swamps and of the different types of 



PHOTOGRAPH OF FOREST AND FARM LAND TAKEN FROM AN AIRPLANE 



The skilled observer is enabled by such a photograph as this to map in one hour as much country as a crew of men can do in a month and 

 tenth the cost and with much more detail and accuracy, giving at the same time the areas of lakes, swamps, of burned land, and the 

 different types of timber. 



in one afternoon to see that it did not contain enough 

 timber to warrant paying the price asked. 



The different species of trees shown up with remark- 

 able clearness from the air and the topography, camps, 

 roads and trails can be seen, and the shallows in the 

 lakes and rivers can be picked out. Logs left in the 

 rivers and lakes by the drives of the previous year can 

 be readily seen and photographed and if the number in a 

 unit area on a photograph are counted and the area 

 measured with a planimeter, a much closer estimate of 

 the number in any body of water can be obtained than 

 by having a man look at them from the shore and guess. 



It is the intention, during the coming season, to take 



timber. The cost of the aerial work too, is only about one- 

 tenth of that of the ground work. The photographs are 

 eight by ten inches and the best altitude for this work is 

 about five thousand feet, which gives a scale of 400 feet 

 to the inch. 



We have a party in the woods now studying the inter- 

 pretation of the forest photographs and have already 

 found that we can draw the boundaries of the timber 

 types with great accuracy, and that in many cases we 

 can draw contours. Individual trees in the photographs 

 can be easily located and species can be distinguished. We 

 are now studying areas which seem to be typical on the 

 photographs, calipering every tree which enters the crown 



