SEAPLANES IN FOREST MAPPING 5 



As to making estimates of timber from photographs, it is possible 

 for pure softwood stands. For mixed stands it is still out of the 

 question in the present state of our knowledge. I think, however, that 

 as we proceed wath our studies we shall be able to do something along 

 these lines. Lakes, rivers, and creeks can be seen and measured 

 accurately, even where creeks are partly hidden by trees their courses 

 may be followed. Roads, trails, and portages where not too over- 

 shadowed can be traced. Camps, dams, booms, and depots show up 

 well. Logs in rivers show up well and photographic reports of the 

 progress of drives will be of value. Swamps, burns, and pure softwood 

 stands can be seen and delimited easily, in open country the character 

 of the soil is shown by the light color of the sand. Rock out-crops 

 where burns are deep show up with startling clearness. One can see 

 whether burns are reproducing or not and can tell the kind of repro- 

 duction, whether hardwood or softwood. Under our conditions, it 

 cannot be told whether a hardwood-softwood stand has been lumbered 

 or not, except that camps and roads can be seen. No estimate can be 

 made of the proportions of species in mixed stands from photos. The 

 index of reflection for softwood is so nearly that of the ground some- 

 times that we cannot be sure whether dark spots in mixed stands are 

 holes or softwoods. 



In order to read the photos, experiments are being made. Areas 

 which appear typical on photos are being carefully cruised on the 

 ground to see if they can be used as standards in reading. Oblique 

 photos promise some help. "Close ups" taken at 500 to 1,000 feet 

 may help. Panchromatic films and films sensitive to different colors 

 will be tried, with and without light filters. Much has already been 

 accomplished by an intensive study of photos on the ground. It is 

 hoped that shortly a technique of interpretation can be worked out 

 similar to that used in reading military photos. 



The writer feels that aerial work is destined to play a large and 

 important role in the work of the forester, particularly in inaccessible 

 and unmapped country and in making the progress reports which are 

 so necessary. It will eliminate an immense amount of drudgery and 

 allow of rapid and relatively accurate reconnaissance work which has 

 been entirely out of the question in the past, as for instance the 

 reconnaissance of whole states, provinces or regions which would in 

 the ordinary course take years to accomplish and whose cost would be 

 prohibitive. 



In regard to the cost of the work. It is probable, basing the predic- 

 tion on actual work done, that complete photographic maps may be 

 turned out at not to exceed $35 per square mile. The areas in timber 

 can be marked off and ground estimates made. 



