70-MM. Aerial Photography—A Remote Sensing Tool for 
Wild Land Research and Management’ 
JACK N. REPPERT and RICHARD S. DRISCOLL ? 
New remote sensing techniques will be 
widely used in wild land research and manage- 
ment in the years ahead. A review of our ini- 
tial efforts with one facet of remote sensing— 
large-scale 70-mm. color aerial photography— 
will stimulate appreciation of its vast poten- 
tial. This potential can be categorized into 
possibly valuable applications with unique ad- 
vantages. This system can ultimately be re- 
lated to more powerful sensor systems, whose 
efficient use awaits only research and develop- 
ment. 
EMERGENCE OF 70-MM. AERIAL 
PHOTOGRAPHY 
While applications of many facets of remote 
sensing—radar, thermal sensors, etc.—are rel- 
atively new to range and related fields, photog- 
raphy is not. In past years, small-scale 
(1:15,000 to 1:20,000 and smaller) aerial pho- 
tography has been used, mostly to delineate 
only very broad vegetation types and physical 
features. And even that part of the three-step 
procedure for determining range condition 
trend that requires oblique ground photogra- 
phy every 5 years depends partly on remote 
sensing. 
Few range and wildlife researchers have ap- 
preciated and fully used the potential within 
conventional aerial photography. We left it to 
the foresters with the thought “it’s difficult 
enough to detect, identify, and measure a pine 
tree, not to mention a bitterbrush or Idaho fes- 
cue plant.” 
The breakthrough that now permits detec- 
tion of small grassland and shrubland features 
centers around recent technological advances 
in camera systems and films that permit 
large-scale, overlapping aerial photographs of 
high resolution to be obtained. In 1953, Losee 
called for the use of large-scale photographs to 
obtain more efficient timber estimates. Sev- 
* Research reported herein was conducted in cooper- 
ation with David M. Carneggie, School of Forestry, 
University of California, Berkeley, Calif., and R. C 
Heller and other personnel of the Forestry Remote 
Sensing Project, USDA, Forest Service, Pacific South- 
west Forest & Range Experiment Station, Berkeley, 
Calif. 
* Principal Range Scientist and Range Scientist, re- 
spectively, Rocky Mt. Forest and Range Exp. Sta., 
USDA Forest Serv.; central headquarters is maintained 
at Fort Collins, Colo., in cooperation with Colo. State 
Univ. 
190 
enty-mm. camera systems with rapid film 
transport and fast shutters (1/1,000 second or 
faster) were suggested as the best solution to 
the image motion problem associated with 
large-scale photographs (Heller et al. 1964).* 
Aldrich (1966) lists several other advantages 
of 70-mm. camera systems; these include low 
cost, light weight, interchangeable lens, nar- 
row angles of view, and film easy to process 
and use in the roll. 
High-speed color film, adaptable to the 70- 
mm. camera system and exposed at large 
scales, has more potential for species differen- 
tiation than ordinary black and white film be- 
cause there are about 20,000 color combina- 
tions distinguishable to the human eye, versus 
200 shades of gray on black and white film. 
More differentiation can be obtained by using 
color infrared film, which is sensitive to green, 
red, and near infrared wave lengths of light 
(blue light is omitted by using a Wratten 12 
filter). Resulting photographs exhibit a false 
color effect. For example, reddish brown soil 
appears green on the film, and healthy, vigor- 
ous, green vegetation appears as some shade of 
pink or red. 
Large-scale photography can be used for (1) 
tree species identification (Sayn-Wittgenstein 
1960, Heller et al. 1964), (2) tree volume esti- 
mates (Kippen and Sayn-Wittgenstein 1964, 
Lyon 1967, and Weber 1965), and (3) forest 
health determination (Aldrich 1966). 
Because of this successful use of large-scale 
photography in forestry, it is only natural that 
such a system might prove to be a useful sam- 
pling tool for shrublands and grasslands (Car- 
neggie and Reppert 1969). 
NEW STUDIES STARTED 
In 1967, three feasibility studies were 
started. The objective was to find the useful- 
ness of two types of aerial film (Anscochrome 
D-200 and Ektachrome Infrared Aero) taken 
at various times during the growing season at 
large scales (1:650 to 1:4,600) for detection, 
identification, and measurement of herbaceous 
and shrubby species and other range features. 
If the system showed promise for these pur- 
poses, a procedure could be developed to use 
this photography system in range inventory 
procedures. 
One study was located at Harvey Valley, 
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