Observations on the impact of western spruce budworm on the Valley Creek Drainage, Flathead Indian Reservation, Montana
By: by Wayne Bousfield ... [et al.].
Contributors: United States. Forest Service. Northern Region. State & Private Forestry.
Series: Insect and disease report; Report -- no. 73-17.; Report (United States. Forest Service. Northern Region) -- no. 73-17.
Publisher: USDA, Forest Service, Northern Region, Division of State and Private Forestry
Published: 1973
Place of publication: Missoula, Mont
Language: eng
Subjects: Western spruce budworm -- Montana -- Flathead Indian Reservation.
Description: The western spruce budworm, Choristoneura occidentalis (Free.), has caused a measurable impact on a portion of the Flathead Indian Reservation during a 5-year infestation period. This survey showed that most of the grand fir and alpine fir, and 13.8 percent of the Douglas fir has been top killed in the Valley Creek area west of Arlee, Montana. The survey also disclosed that a total net growth loss of 19.6 1.9 board feet per acre per year has occurred since 1967. Significant growth reduction at the 99 percent level occurred in Douglas-fir, grand fir, alpine fir, and western larch. Little mortality in trees 5 inches d.b.h. and greater has occurred to date. Of the trees under 5 inches d.b.h. 55.6 percent were not suitable for Christmas tree production because of insect damage.
Notes: Caption title.

"July 1973."

Includes bibliographical references.

Also issued online.