INTRODUCTION 
Extensively managed lands are those lands whose vastness precludes 
intensive managements. Such lands,' exclusive of agriculture crops, are usually 
open to forest exploitation, or grazing by wild mammals or domestic livestock. 
In rare instances some areas have been reserved as "wilderness" and eliminated 
from aspects of commercial exploitation. Across all these lands a need resides 
to monitor the "health" of the vegetation since poor health means "damaged" 
vegetation, and damaged vegetation usually means a loss of potentially commer 
cial or recreational values. Over forested lands this is caused by either 
insect or disease damage, air pollution, wind storms, or fire. Over range lands, 
the damage is caused by drought, fire, insects or overgrazing. This paper 
reports on the present capability to monitor vegetation for indications of 
damage through, remote sensing and interpretation techniques, as indicated by 
published reports in the literature known to the author. Future needs are 
speculated upon. 
RECENT LITERATURE 
In 1971, Heller, in a general paper on interpretation of color and 
false-color photographs, outlined the state of photo interpretation for forest 
vegetation damage interpretation. Some of the points made in the paper are 
viewed in retrospect and commented upon here: 
1. The usefulness of various photographic scales using either color or 
color-infrared film had either not been tested or was considered 
not useful. For example, delineation of spruce budworm ( Choristo- 
neura fumiferana Clem.) defoliation on color-infrared photos had not 
been tested, and only large-scale (1:600 to 1:2,000) color photos 
were considered good for damage delineation. At photographic scales 
smaller than 1:15,840, both color and color-infrared photos were 
considered not useful for oxidant air-pollution interpretation, oak 
wilt interpretation, and balsam woolly aphid ( Adelqes pioea (Ratz.) 
damage. 
2. The use of normal-color air photos had not been tested for either 
dwarf mistletoe ( Avouethobium spp.) or the ubiquitous Dutch elm 
disease (i Ceratocystis ulmi (Buism) C. Moreau). But studies had been 
done on oak wilt ( Ceratooystis fagacearum (Bretz) Hunt) and small 
scale (1:15,840 or smaller) photos were considered not useful. 
3. Photo interpretation of forest damage was being done on a piecemeal 
basis according to the "classical textbook" breakdown of insect and 
diseases into bark beetles, sucking insects, defoliators, terminal 
feeders, air pollution, Dutch elm disease, oak wilt, etc. It is now 
apparent that a) each bark beetle seemed to be listed separately and 
special studies designed for that particular insect; b) very little 
emphasis was given to the final appearance of the damage syndrome, 
and c) such a piecemeal approach to individual insects and diseases