Stand and tree characteristics influencing density of fir engraver beetle attack scars in white fir

George T. Ferrell

Treesearch

Stand and tree characteristics influencing density of fir engraver beetle attack scars in white fir

Informally Refereed

Authors:

George T. Ferrell

Year:

1973

Type:

Research Paper

Station:

Pacific Southwest Research Station

Source:

Res. Paper PSW-RP-097. Berkeley, CA: Pacific Southwest Forest and Range Exp. Stn., Forest Service, U.S. Department of Agriculture; 8 p

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Download (PDF 402 KB): https://research.fs.usda.gov/download/treesearch/23979.pdf

Abstract

Density of embedded scars resulting from old fir engraver (Scolytus ventralis Lec.) attacks was assessed in 3,430 bole cross sections cut from 603 white firs growing in both cutover and in virgin old-growth stands in northern California. Mean scar density was directly related to percentage of mature stand removed by logging and was higher in suppressed and intermediate, compared to dominant, fir. Inverse relationships were found between scar density and site quality, tree diameter, height, age, volume, and mean growth rate. A risk rating system based on tree and stand characteristics appears possible and would be useful in identifying for removal white fir with decreased resis-tance to beetle attacks. Such trees might also have a high probability of lumber defects caused by high scar densities.

Keywords

Abies concolor, Scolytus ventralis, predator-host relations, damage indexes, attack scars, tree vigor, host resistance, host tree mortality, risk rating, lumber defects

Citation

Ferrell, George T. 1973. Stand and tree characteristics influencing density of fir engraver beetle attack scars in white fir. Res. Paper PSW-RP-097. Berkeley, CA: Pacific Southwest Forest and Range Exp. Stn., Forest Service, U.S. Department of Agriculture; 8 p