File:Bark beetle and wood borer infestation in the Greater Yellowstone Area during four postfire years (1996) (20344959962).jpg

English: Mortality of Engelmann spruce totaled 41 percent of the 439 trees in the sample: 31.9 percent were killed by fire injury, 6.6 by insects, and 2.5 percent died from unidentified factors (fig. 4). Spruce beetle (Dendroctonus rufipennis [Kirby]) killed almost one- half of the spruce killed by insects. Other insects that caused spruce death were Ips pilifrons Swaine and wood borers of families Buprestidae and Cerambyci- dae. The high loss of spruce to fire injury is related to thin bark, which causes them to be easily killed by fire.

Title: Bark beetle and wood borer infestation in the Greater Yellowstone Area during four postfire years
Identifier: barkbeetlewoodbo487rasm (find matches)
Year: 1996 (1990s)
Authors: Rasmussen, Lynn A; Intermountain Research Station (Ogden, Utah)
Subjects: Bark beetles Yellowstone National Park; Wood borers Yellowstone National Park; Trees Diseases and pests Yellowstone National Park; Forest fires Yellowstone National Park
Publisher: Ogden, UT : U. S. Dept. of Agriculture, Forest Service, Intermountain Research Station
Contributing Library: U.S. Department of Agriculture, National Agricultural Library
Digitizing Sponsor: U.S. Department of Agriculture, National Agricultural Library

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100 80 0 Douglas-fir (Pseudotsuga menziesii) Green Fire Insect Unknown mortality Stand Composition (present) Figure 2—Alive (green) and dead Douglas-fir by cause of mortality. Most infestation was by the Douglas-fir beetle. Addi- tional mortality, especially of small diameter trees, was caused by Pseudohylesinus nebulosus LeConte and wood borers. These data show that almost one-third of the Dou- glas-fir that were green and considered alive following the 1988 fires died from delayed effects of fire or in- sect infestation. Where mortality is evenly distributed, the fire-killed and green Douglas-fir mosaics appear slightly affected. However, where mortality is con- centrated, drastic altering of the mosaic is apparent. On the other hand, lodgepole pine mortality con- sisted of 51.6 percent of the 4,758 sampled trees. This breaks down to 30.5 percent due to fire injury, 17.9 percent due to insects, and 3.2 percent to unidentified causes (fig. 3). All trees retaining green foliage after the 1988 fires may be considered survivors of the fires. However, even though they still had green foliage, green phloem, and appeared alive, almost two-thirds of the lodgepole that subsequently faded had been com- pletely girdled by light ground fires. Many of these trees' deaths from fire injury were not apparent even 3 to 4 years after the fires, and quite often not until the lodgepole were infested by the pine engraver dps pini (Say)) or the twig beetles, Pityophthorous confer- tus Swaine and Pityogenes knecteli Swaine, did rapid fading occur. Of all the lodgepole pine that died from all causes, including fire injury, 44 percent were in- fested by the pine engraver. Mountain pine beetle, Dendroctonus ponderosae Hopkins, infested only 0.8 percent of the lodgepole. In this data set, and as observed by others (Blackman 1931; Hopkins 1905), mountain pine beetle is not strongly attracted to fire-injured trees. In addition to the stress of fire injury, trees had been subjected to drought for several years. These stress factors did not significantly increase nor precipitate an out- break of mountain pine beetles, which again points to uniqueness in terms of lack of response to stress factors that are commonly associated with Douglas- fir beetle and pine engraver infestations. Mortality of Engelmann spruce totaled 41 percent of the 439 trees in the sample: 31.9 percent were killed by fire injury, 6.6 by insects, and 2.5 percent died from unidentified factors (fig. 4). Spruce beetle (Dendroctonus rufipennis (Kirby)) killed almost one- half of the spruce killed by insects. Other insects that caused spruce death were Ips pilifrons Swaine and wood borers of families Buprestidae and Cerambyci- dae. The high loss of spruce to fire injury is related to thin bark, which causes them to be easily killed by fire. Subalpine fir had 37.3 percent survival of the 134 trees in our sample. Most mortality was attributed Lodgepole pine (Pinus contort a) .t—y-) Green Fire Insect Unknown mortality Stand Composition (present) Figure 3—Alive (green) and dead lodgepole pine by cause of mortality.
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Green Fire Insect Unknown mortality Stand Composition (present) Figure 4—Alive (green) and dead Engelmann spruce by cause of mortality. 4

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