Western spruce budworm as related to stand characteristics in the bitterroot national forest

Carroll B. Williams; Patrick J. Shea; Gerald S. Walton

Treesearch

Western spruce budworm as related to stand characteristics in the bitterroot national forest

Informally Refereed

Authors:

Carroll B. Williams, Patrick J. Shea, Gerald S. Walton

Year:

1971

Type:

Research Paper

Station:

Pacific Southwest Research Station

Source:

Res. Paper PSW-RP-072. Albany, CA: Pacific Southwest Research Station, Forest Service, U.S. Department of Agriculture; 13 p

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Abstract

Relation of population density to certain stand conditions and damage indicators was analyzed in four drainages on the Bitterroot National Forest of Montana. Western spruce budworm (Choristoneura occidentalis Freeman) populations were strongly related to plot basal area, tree species, and tree crown levels, and also to current and past levels of tree defoliation. Relatively open stands of thrifty trees are recommended, with logging of true fir and Douglas-fir to favor nonhost trees, to reduce vulnerability to excessive budworm damage.

Keywords

Choristoneura occidentalis, population dynamics, site factors, basal area, Pseudotsuga menziesii, Picea engelmannii, Abies spp, mortality, Bitterroot N F

Citation

Williams, Carroll B., Jr.; Shea, Patrick J.; Walton, Gerald S. 1971. Western spruce budworm as related to stand characteristics in the bitterroot national forest. Res. Paper PSW-RP-072. Albany, CA: Pacific Southwest Research Station, Forest Service, U.S. Department of Agriculture; 13 p