30 HISTORY OF PHOTOGRAMMETRY IN THE UNITED STATES 
employees engaged in photogrammetric 
work. . 
The foregoing should not be construed 
to mean that mapping was the only use 
being made of aerial photos. From the 
first, photographs were studied with avid 
interest by foresters in other lines of work. 
Timber, range, and experiment station 
personnel realized that better appraisal 
and survey work at lower costs could be 
effected by use of pictures. Fire Control 
was using aerial photos extensively and 
effectively. In 19397 Burk and Wilson of 
the California Forest Range Experiment 
Station presented results of a vegetative 
inventory from aerial photographs, and in 
19423 Wieslander and Wilson published an 
excellent account of work in connection 
with classifying forest and other vegeta- 
tion from aerial photos. Moessner, Jensen, 
Rogers, Colwell, Garver, and numerous 
others have contributed effectively to the 
ever-increasing use of aerial photographs. 
The use of aerial photographs in the 
many activities of the Forest Service is 
almost infinite. It is doubtful if any one 
government agency or private company 
has such varied use for the photos. They 
are being used extensively in nearly all 
phases of fire control work. No grazing 
survey is undertaken without aerial pic- 
tures being available. The accuracy of 
timber and forest surveys is greatly in- 
creased, and the cost cut about 50% over 
previous methods, by using photos. Their 
use in reconnaissance for road location 
work has saved a great deal of time and 
money, and experiments in the Alexandria 
Mapping Office involving the use of the 
Kelsh Plotter for road location have given 
very gratifying results.* Recent work on 
cadastral surveys, somewhat dormant since 
the original work in 1934 and 1935, in- 
dicate that improved methods and equip- 
ment will effect a substantial saving in 
future work of this nature. 
Photos have been used in the past few 
years for planning and mapping work in 
connection with control work on blister 
rust, Tussock Moth and other types of 
timber infestation. They have been used 
for years in wildlife management programs, 
for erosion and flood control planning, for 
planning and developing recreational and 
winter sports areas, for land exchange and 
mineral surveys, for law enforcement and 
trespass cases, and for dozens of other 
related uses. There is scarcely a field job 
undertaken by a Forest Service employee 
in which aerial photographs cannot be 
used to more efficiently perform the work. 
Aerial photographs and photogram- 
metry have long since proved to be in- 
dispensable and valuable tools in the hands 
of foresters. Constant improvement in 
photogrammetric equipment, techniques, 
and processes, together with a definite 
personnel training program in the use 
thereof, can contribute greatly to even 
more efficient and economical Forest 
Service work in the future. 
In the limited time available for prep- 
aration of this “thumbnail” history of 
photogrammetry in the U. S. Forest 
Service, only the highlights could be 
touched upon. A multitude of people have 
contributed to the science, and its progress 
is indicated by the hundreds of papers 
which have appeared in our leading: 
scientific publications. It is regretted that 
it is not possible to mention all who have 
been instrumental in furthering the sci- 
ence, and that a complete historical bib- 
liography can not be prepared at this time. 
REFERENCES 
1. Thelen, Rolph, “Aerial Photography and 
National Forest Mapping,” Journal of 
Forestry, Vol. 17, 515-522, 1919. 
2. Minutes of the first U. S. Forest Service 
Surveys and Maps Conference, held at Mis- 
soula, Montana, 1936. 
3. Massie, E. S., “Forest Service Planimetric 
Maps,” PHOTOGRAMMETRIC ENGINEERING 
Vol. VI, No. 4, 151—155, 1940. 
4. Wright, Marshall S., "Aerial Surveys in 
Colorado,” The Military Engineer, Vol. 
XXV, No. 142, 301-303, July-August 1933. 
5. Wright, Marshall S., Region 7 Report of 
September 11, 1935, under designation EM- 
Surveys, Aerial. 
6. King, Jasper E. "The K.E.K. Plotter," 
PHOTOGRAMMETRIC ENGINEERING, Vol. X, 
No. 4, 252-260, 1944. 
7. Burks, G. F., and Wilson, R. C., "A Vege- 
tative Inventory from Aerial Photographs," 
* The Forest Service is using photogrammetry for many phases of road work but has not yet 
found a way of setting slope and grade stakes by photogrammetry—T.W.N.