Description:
In spruce budworm damaged areas, height growth loss can be a major factor in stand development. This survey was confined to top-killed trees. Estimates on height growth loss or nontop-killed trees was not attempted. Although spruce did not have as high a percentage of trees top-killed as the true firs, it did result in a greater amount when expressed in number of years. This may have been because spruce was larger and the growth model projected slower height growth on these trees. Subalpine fir had the highest percentage of host trees top-killed (21.2 percent), but the period affected was the shortest. Subalpine fir average length of top-kill for both light and moderate severity classes was less than the other species, therefore not as many years were involved in height growth loss. Height growth of Douglas-fir was not affected in this stand. This confirms previous observations that Douglas-fir is not severely damaged in mixed host types in northern Idaho.