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Western Spruce Budworm Damage Model

The Western Spruce Budworm Damage Model simulates Choristoneura occidentalis Freeman, Lepidoptera: Tortricidae.

Western Spruce Budworm
Adult moth of the western spruce budworm on a spruce needle
Photo by Dave Powell, USDA Forest Service, www.forestryimages.org
 
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Insect Description

Western Spruce Budworm Damage Model, Choristoneura occidentalis (590 KB PDF)

Model Description

The Western Spruce Budworm (WSB) Damage model, an extension to the Forest Vegetation Simulator (FVS), predicts topkill, height growth, diameter growth, and tree mortality impacts of western spruce budworm (Choristoneura occidentalis Freeman) defoliation on its spruce and fir host tree species (Crookston 1991). This model is formed from two components of the Western Spruce Budworm Modeling System (Sheehan et al. 1989, Crookston et al. 1990): foliage dynamics and damage. The complete modeling system represented complex budworm population dynamics, but is no longer in service.

The damage model allows users to specify defoliation patterns by tree species, size class, crown third, and needle age class (Crookston et al. 1990). There are three size classes and four foliage age classes defining the foliage/defoliation patterns for each budworm host species. The damage model is not responsive to changing stand conditions and requires users to make detailed predictions about defoliation patterns for the entire simulation period. For the user's evaluation of the specified defoliation patterns, there are two output tables available: a cumulative damage summary and periodic damage tables at each FVS cycle boundary, displaying the results of budworm defoliation on FVS model trees.

Crookston, Nicholas L., J.J. Colbert, Paul W. Thomas, Katharine A. Sheehan, and William P. Kemp. 1990. User's guide to the western spruce budworm modeling system. Gen. Tech. Rep. INT-274. Ogden, UT: U.S. Department of Agriculture, Forest Service, Intermountain Research Station. 40 pp.

Crookston, Nicholas L. 1991. Foliage dynamics and tree damage components of the western spruce budworm modeling system. Gen. Tech. Rep. INT-282. Ogden, UT: U.S. Department of Agriculture, Forest Service, Intermountain Research Station. 40 pp.

Sheehan, Katharine A., William P. Kemp, J.J. Colbert, and Nicholas L. Crookston. 1989. The western spruce budworm model: structure and content. Gen. Tech. Rep. PNW-Gtr-241. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station. 70 pp.

 

Documentation

Intermountain Research Station
Gtr-INT-274
September 1990

Western Spruce Budworm Damage Model User's Guide (4.5 MB PDF)

 

Executables

FVS Variant Files (Website)

 

Related Topics

    Western Root Disease Model
    Douglas-fir Beetle Model
    Douglas-fir Tussock Moth Model
    Dwarf Mistletoe Model
    Lodgepole Mountain Pine Beetle Model
    Western Spruce Budworm Damage Model
    White Pine Blister Rust Model
    Multiple Insect and Disease Models
    Westwide Pine Beetle Model
    FVS BGC Model

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