Detection of Dwarf Mistletoe in Young-Growth Ponderosa Pine From Color Aerial Photography

The purpose of this study was to determine if infection levels of dwarf mistletoe on ponderosa pine could be detected with color aerial photography. The photography was taken in early September using Kodak Ektachrome Infrared Aero and Ektachrome Aero films at scales of 1/4000, 1/2000, and 1/1000. Ground truth consisted of 214 trees classified as to healthy, lightly infected, moderately infected or heavily infected. Three photo interpreters were able to correctly classify these trees only 34 per-cent of the time. Statistical analysis indicated no significant dif-ferences between interpreters, film types, scales, or levels of infec-tion. Rearrangement of the data did indicate that four interpreters were able to distinguish mistletoed from non-mistletoed trees 70 per-cent of the time using Ektachrome Infrared Aero film at a 1/1000 scale. Results might be improved by using low oblique photography Abstract approved: Signature redacted for privacy. taken in the spring with either Kodak Ektachrome Aero or Ektachrome Infrared Aero films, at a scale of 1/1000