42 REPORT OF COMMISSION VII
with no loss in accuracy of estimates. Further work along these same lines holds
promise of important contributions for the future.
The measurement of slopes on aerial photographs finds use in many phases
of inventory work. Numerous methods have been proposed in the past for use
by the geologist, soil surveyor, and others. Some methods are not applicable
where photoscale cannot be accurately determined, and others are too complex.
There is need for a simple device which will yield reasonably accurate results.
At least one investigator is working on such a device now, which may find wide
acceptance when perfected.
Many other ideas relating to the use and techniques of aerial photos in
natural resource inventories have been provided by the questionnaire respond-
ents, and by the many publications which deal with the subject. The summary
which is given here covers such a broad field that it cannot be expected to pro-
vide needed details. The reader, therefore, is encouraged to search the literature
relating to his own field of interest, to take an active part in meetings, and to
engage in correspondence with those whose interests are the same as his.
RESFONDENTS TO QUESTIONNAIRES*
Wood, Waldo E. U. S. Forest Service, California
Lommasson, Thomas U. S. Forest Service, Montana
Bongberg, J. W. U. S. Bureau of Entomology and Plant
Quarantine, California
Harris, Thomas U. S. Bureau of Entomology and Plant
Quarantine, California
Dasmann, William Dept. of Fish and Game, California
Ragland, W. W., Col. U. S. Army Engineers, Snow Investigations,
California
Merriam, L. C. National Park Service, California
Kalmbach, E. R. Fish and Wildlife Service, Colorado
Schultz, Vincent Game and Fish Commission, Tennessee
Wilson, R. C. U. S. Forest Service, Oregon
Casamajor, Paul Shasta Forests Co., California
Waha, H. B. U. S. Forest Service, New Mexico
Grant, Burton S. Los Angeles Dept. of Water and Power,
California
Ashcraft, Gordon Dept. of Fish and Game, California
Brundall, Laurence Geophoto Services, Colorado
Bushnell, T. M. Purdue University, Indiana
Cosma, Duilio Corpo Forestale, Italy
Pillewizer, Wolfgang München, Germany
{Raindsalo, Aarne Helsinki, Finland
{Imhof, Edouard Sederlele, Switzerland
{Thoren, Ragnar Stockholm, Sweden
TDrabbe, C. A. J. von Frijtag Delft, Holland
{Baetzle, Major Etterbeek, Belgium
LITERATURE CITED
Andrews, G. S., 1940, “Notes on the Interpretation of Vertical Air Photographs," Forestry Chron.,
16: 202-215.
Anon, 1951, “Log Inventory Taken from the Air,” The Timberman, 52 (5): 127, March 1951.
* List does not include respondents to questionnaires distributed by subphase delegates.
T Replies not yet received at time of compiling list.