846 
CAN MOUNTAIN PINE BEETLE GREEN ATTACK BE DETECTED ON HIGH RESOLUTION DATA 
FROM A DIGITAL AIRBORNE IMAGER? 
PRELIMINARY RESULTS 
I. D. Kneppeck 
Dendron Resource Surveys Ltd. 
880 Lady Ellen Place 
Ottawa, Ontario K1Z 5L9 
613-725-2971 
F. J. Ahern 
Canada Centre for Remote Sensing 
1547 Merivale Road 
Ottawa, Ontario K1 A 0Y7 
613-952-2746 
ABSTRACT 
The Mountain Pine Beetle (Dendroctonus ponderosae Hopk.) and related bark beetles are the most serious 
insect pests damaging the forests of western Canada. The preferred control strategy is to remove infested 
trees before the beetles emerge and spread the infestation. Despite much effort by a number of researchers 
to develop remote sensing methods to detect infested trees at the early "green attack" stage, early detection 
has proven to be a very elusive goal. Successful detection has been reported using high resolution (1:2000 
scale) colour infrared photography, but the high costs of surveys at these large scales make the method 
impractical for operational use. 
In 1986 the Canada Centre for Remote Sensing (CCRS) began a cooperative project with the British Columbia 
Ministry of Forests to improve the use of remote sensing technology for mapping mountain pine beetle attack. 
Foliar spectroscopic studies carried out under that project identified the spectral bands best suited for 
detecting green attacked trees. In addition, a study with the airborne MEIS (Multi-element Electro-optical 
Imaging Sensor) showed that high spatial resolution was necessary to detect trees at the "red attack" stage, 
and implied that high resolution would also be necessary for detecting green attack. 
In 1989 CCRS and the Ministry of Forests acquired data for a study of the use of MEIS data for distinguishing 
green attacked lodgepole pine (Pinus contorta Dougl. var. latifolia Engelm.) from unattacked lodgepole pine. 
The area chosen was located approximately 35 km southeast of Cranbrook, B. C. MEIS data at 0.4 m, 1.0 m, 
and 2.2 m resolution were acquired over the study area on 1989.09.01. A sample of 256 infested trees and 250 
unattacked trees were identified in four principal areas on the ground and on colour infrared aerial 
photography acquired simultaneously with the MEIS data. The trees used in this study were infested during 
the summer of 1989 and their foliage was still green with no visual sign of weakening or discolouration at the 
time of the ground sampling, 1989.10.02 through 1989.10.05. 
Spectral features were analyzed using visual enhancement techniques and digital measures of the separability 
between the attacked and unattacked classes. The results showed larger differences occurring between sites 
than between the attacked and unattacked trees. 
KEYWORDS: MEIS, colour infrared photography, mountain pine beetle, green attack, digital image analysis 
1. INTRODUCTION 
The mountain pine beetle (Dendroctonus ponderosae 
Hopk.) is the most destructive pest of lodgepole 
pine (Pinus contorta Dougl. var. latifolia Engelm.) in 
British Columbia. In fact, the annual allowable cut 
was increased approximately 59 percent for the 
Cranbrook, British Columbia timber supply area for 
a period of three years starting in 1989 in order to 
combat the mountain pine beetle problem (Ministry 
of Forests News Release, 1989). 
The life cycle of the mountain pine beetle and 
methods used to reduce losses have been described 
elsewhere (Safranyik et at, 1974). By the time the 
tree visually appears attacked and needles have 
turned red, one year following initial attack, beetles 
have often already left the tree and spread to 
adjacent trees. Shortening the detection time of 
trees infested with beetles, such that trees can be 
removed before beetles emerge to infect other trees 
could, in principle, slow the spread of an attack and 
help keep down the beetle population. Methods 
currently used to detect trees in the green attack 
stage, when the needles are green and beetles are 
still in the tree, include ground inspections. 
Symptoms of this phase of infestation are reddish- 
brown boring dust found at the base of freshly 
attacked trees, and the presence of pitch tubes 
which usually form around entrance holes on the 
bark in the summer of attack. 
Investigations into the early detection cf beetle 
attack involving the use of colour infrared aerial 
photographs have been successful. Hobbs and 
Murtha (1983) were able to correctly classify new