Invasive Species Compendium

Detailed coverage of invasive species threatening livelihoods and the environment worldwide

Abstract

Susceptibility of white spruce to attack by spruce beetles during the early years of an outbreak in Alaska.

Abstract

Twenty-five variable sample plots were examined in mature stands in the Canyon Creek/Quartz Creek valley on the Kenai Peninsula, infested by spruce beetle (Dendroctonus rufipennis) since 1978. Diameter was not an important criterion for spruce susceptibility to attack or death unless large diameter was coupled with slower than average radial growth in the last 5 yr. A sigmoid transformation of percent mortality of spruce was inversely related to the logarithm of mean cumulative radial growth of spruce in the last 5 yr and was directly related to number of spruce per hectare greater than 24.1 cm in diameter. This relationship is portrayed graphically as a rudimentary stand hazard rating model.