VEGETATION DAMAGE AND REMOTE SENSING: 
PRINCIPAL PROBLEMS AND SOME RECOMMENDATIONS 
by 
Peter A. Murtha 1 
INTRODUCTION 
In a previous paper (Murtha 1976), considerations for promis- 
ing ways to inventory and monitor forest insect diseases and damages 
were discussed. A four part, dynamic flexible system consisting of 
airborne, photo development, interpretation and evaluation phases was 
presented as a necessary avenue to accomplish remote sensing of vege- 
tation damage. The system was tied to a holistic approach of vegetation 
damage interpretation and evaluation by remote sensing techniques. 
Generally, it is concluded that there is no one most suitable way to 
inventory and monitor vegetation damage, and each damage situation must 
be answered by the flexibility of the system. But there are problems 
in the system, both technical and philosophic that must be discussed in 
view of current techniques and attitudes. It is the purpose of this 
paper to discuss the principal problems and provide some recommendations. 
DEFINITIONS 
A problem of terminology concerning the words "remote sensing" 
must be dealt with first. By remote sensing, I mean remote analysis, 
which includes the airborne sensing system, data interpretation including 
photogrammetry, and subsequent deduction of an answer. Photo interpre- 
tation is the same concept, except that it excludes any thought of the 
sensing system, with the primary emphasis on the deduction of the answer. 
These definitions are included to indicate that remote sensing has 
existed for a long time, before the advent of satellite technology, and 
that we should not narrow our thinking to the equation: remote sensing = 
satellite technology. Satellites are considered as one stage of a multi- 
stage sensing system, and one data source from a whole range of sources. 
Thus, remote sensing is the methodology, damage to vegetation is the 
target of the methodology. 
"Damage" is the second word that needs defining because of 
confusion found in the literature. Harris (1974) was very precise in 
referring to damages, and was quite specific in separating "tree mortality", 
from "dying trees", from "defoliating pest infestations", from "trees 
killed by bark beetles." Weber and Polcyn (1972) were also very specific 
in describing another category of damaged trees: "faded trees" as 
  
1 
Assistant Professor, Faculty of Forestry, University of British Columbia, 
Vancouver, B.C. V6T 1W5, Canada.