Canadian Forest Service Publications

Assessment of aerial photographs and multi-spectral scanner imagery for measuring mountain pine beetle damage. 1992. Gimbarzevsky, P.; Dawson, A.F.; van Sickle, G.A. Forestry Canada, Pacific Forestry Centre, Victoria, BC. Information Report BC-X-333. 31 p.

Year: 1992

Issued by: Pacific Forestry Centre

Catalog ID: 3265

Language: English

Series: Information Report (PFC - Victoria)

Availability: Order paper copy (free), PDF (download)

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Abstract

A survey of mountain pine beetle infestation in a 370-km2 demonstration area was initiated as part of a damage appraisal program conducted by the Forest Insect and Disease Survey of Forestry Canada. The main objective of this study was to investigate the operational use of available remote sensing techniques for identification of beetle-killed forest stands, mapping their areal extent, and measurement of tree damage. Survey procedures involved the mapping of infested stands, acquisition of imagery, image analysis and compilation of volume losses. The acquired imagery consisted of conventional normal color and color infrared aerial photography at scales of 1:56 000, 1:19 000, and 1:8000, supplementary 70-mm color photography of 32 4-ha photo plots at a scale of 1:6000, and 90 stereo pairs at an average scale of 1:1000, a series of 35-mm oblique color slides, and multi-spectral scanner digital data (airborne and satellite). The high-altitude (scale 1:56 000) color infrared aerial photography was used as a main sensor in a stereoscopic analysis of forest conditions. Infestations were delineated on color infrared transparencies and superimposed on 1:20 000 British Columbia Ministry of Forests cover type maps. The size of damaged areas was determined directly from the map for each of some 300 affected cover types. The intensity of infestation and volume losses were compiled from the analysis of photo plots and ground sampling data, and tabulated by map sheets and cover types. A total area mapped as damaged was 4673 ha, with an estimated volume loss of over 453 000 m3 of lodgepole pine, averaging 97 m3/ha. Damage maps were also compiled from digitally processed multi-spectral scanner imagery. They showed the infestation patterns generally comparable to those of high-altitude color infrared aerial photography, but the damaged areas appeared considerably larger. It was not possible to separate different levels of damage intensity on multi-spectral scanner imagery and a proper interpretation of forest conditions required frequent reference to conventional aerial photography. The procedures described in this report are illustrated with numerous color stereograms, oblique photographs, and multi-spectral scanner imagery.