Failure Potential

1
Failure Potential

• Caused by insect-caused damage and mortality

2

• Balsam woolly adelgid is currently causing
  mortality throughout the subalpine fir host type.
  SAF makes a short-lived snag.
• Likely FP lt3 years dead
• Imminent FP if dead gt 3 years, or lt 50 sound due
  to decay and root diseases.

3

• Grand fir is predisposed to fir engraver-caused
  mortality by numerous factors. Sapwood decaying
  fungi are introduced and saprot quickly follows.
• Likely FP lt 3 years dead
• Imminent FP if gt3 years dead, or lt 50 sound.

4

• Sapwood decay on dead trees includes gray saprot
  (pouch fungus) and others. Decay is aggressive.
• FP Likely if gt 50 sound or lt 3 years dead true
  firs and spruce, or lt 5 years dead for pines and
  DF.
• FP Imminent if lt 50 sound or gt3 years dead
  for true firs and spruce, and gt5 years dead for
  pines and DF.

5
Grand fir failures primarily associated with
saprot
6

• Douglas-fir beetle can be expected to breed in
  fire-damaged, diseased, and stressed firs. Decay
  is associated with beetles and wood borers.
  Saprot occurs first and heart rot follows.
  Mortality lt5 years, or saprotlt 50
• FP Likely.
• Mortality gt5 years, or saprot gt 50
• FPImminent.

7

• Defoliators including tussock moth and budworm
  can severely damage Douglas-fir and grand fir
  during outbreaks. Tops are killed and bark
  beetles become active several years into
  outbreaks, causing mortality. Dead trees and
  tops have Likely FP, until tops have significant
  saprot and dead trees are no longer sound they
  then have Imminent FP

8

• Pines are attacked by several different bark
  beetles. Western pine beetle is especially
  active after fires in ponderosa pine and Ips
  beetles can be similarly active in ponderosa and
  lodgepole pines.

9

• Beetle-killed ponderosa pine can fail due to stem
  saprot or decayed roots. For pine lt16 dbh, dead
  lt 5 years, or having lt 50 saprot, and trees gt16
  dbh dead lt10 years or have lt50 saprot.
• FPLikely
• For trees exceeding these guidelines.
• FP Imminent

10
Beetle-killed lodgepole pine

• Lodgepole pine seldom have significant saprot
  while standing due to their thin bark. Blue
  stain does not reduce structural strength.
  However, roots rapidly decay once trees die.
• Lodgepole pines dead lt5 years
• FPLikely
• Lodgepole pines dead gt5 years FPImminent

11
Beetle-killed Engelmann spruce

• Bark beetle-killed spruce can be especially
  dangerous due to the high incidence of tomentosus
  root and butt rot in the Blue Mountains. Trees
  without root disease have Likely FP if dead lt5
  years.

12

• Woodpecker feeding on carpenter ants in this
  beetle-killed spruce indicates a dead tree with
  decay and deterioration that easily qualifies as
  having Imminent FP