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INVENTORY OF BARK BEETLE MORTALITY IN CONIFEROUS FORESTS 
WITH COLOR AND COLOR IR PHOTOGRAPHY 
by 
William M. Ciesla and William H. Klein 
Forest Insect and Disease Management 
Methods Application Group 
USDA Forest Service 
Davis, California, USA 
Abstract 
Coniferous bark beetles are among the most destructive forest insect pests in 
North. America. They periodically reach epidemic proportions, causing extensive 
loss to forest resources.  Timely, accurate inventories on status of outbreaks 
and magnitude of loss are needed for management decisions. Sampling systems 
using color and color IR aerial photography are an effective means of acquiring 
inventory data. 
Data requirements for reporting forest insect and disease losses have been 
defined at two managerial levels, the resource manager who must make "on-the- 
ground" management decisions, and the national or Regional program manager 
where quantitative summaries are required to establish priorities and allocate 
funds for forest pest management activities. 
In 1977, we designed and conducted surveys in lodgepole and ponderosa pine 
forests in Idaho and South Dakota to quantify annual timber mortality by 
mountain pine beetle, Dendroctonus ponderosae. These surveys were designed 
to provide in-place information needed by the resource manager and statistical 
summaries required at the national level. Aerial sketch mapping combined 
with large-scale color photography and ground sampling were used to obtain 
the required data. We are currently evaluating high-resolution, small-scale 
reconnaissance photography (1:30,000) for stratification of outbreaks into 
intensity classes and allocation of second stage samples. 
Introduction 
The bark beetles of the family Scolytidae are among the most damaging insects 
in North American coniferous forests. Insects of the genera Dendroctonus, 
Ips, and Scolytus periodically reach outbreak proportions and cause extensive 
tree mortality. Available data indicate that coniferous bark beetles are 
responsible for up to 90% of the insect-caused tree mortality in the United 
States (USDA 1958). 
Bark beetles are an integral part of the coniferous forest ecosystem in North 
America. They can be instrumental in conversion of pure stands of one 
Species to mixed species forests, or in combination with wildfire create 
conditions favorable for regeneration of vast areas of pure stands of a 
single species. Bark beetle outbreaks undoubtedly have occurred long before 
man made significant use of the forest, and sketchy records of bark beetle