Defective Trees or tree parts with Likely and Imminent Failure Potential

1
Defective Trees or tree parts with Likely and
Imminent Failure Potential
2
Root disease confirmed but tree still alive

• Some root disease are relatively less likely to
  result in tree failure than others. With these
  diseases, toppling usually occurs after trees
  have been dead for several years. Trees with
  these root diseases have Likely Failure Potential
  while alive.
• Annosus root disease (Heterobasidion annosum) on
  pines.
• Armillaria root disease (Armillaria ostoyae)
• Blackstain root disease (Leptographium wagenerii)
• Tomentous root disease (Inonotus tomentosus) of
  spruce seldom has crown symptoms, and is seldom
  killed. Any indicators of extensive butt decay
  would qualify spruce as having Likely to Imminent
  FP.

3
Root disease confirmed but tree still alive
(continued)

• Some root diseases on living symptomatic trees
  are more dangerous than others, frequently
  resulting in toppling while still having a green
  crowns trees with these root diseases are
  classed as having Likely to Imminent FP
• Laminated root rot (Phellinus weirii) of all Blue
  Mnt. conifers
• Annosus root disease (Heterobasidion annosum) of
  true firs
• Schweinitzii root and butt rot (Phaeolus
  schweinitzii) with evidence of decay mostly on
  DF and WL
• Tomentosus root and butt rot (Inonotus
  tomentosus) on spruce with signs/symptoms of
  extensive decay.

4
Tomentosus root disease
Schweinitzii root and butt rot
5
Likely Failure Potential

• Old lean that has not corrected itself
• There should not be any evidence of soil lifting
  or cracking.
• Leaning trees with evidence of soil lifting or
  cracking probably recently developed that lean.
  Such trees are especially dangerous and should be
  classified as having Imminent FP.

6
Likely Failure Potential

• Trees having some undermined or severed roots.
  The Qualified Person makes a judgment call that
  enough anchored root system remains that the tree
  can be given Likely FP.
• Criteria is that no more than one large lateral
  root (Pp) or no more than 25 of the root system
  circumference is damaged.
• Root damage on the uphill side or the side
  opposite of the potential failure zone is of most
  concern (dangerous).

7
Likely Failure Potential

• Rot confirmed in live trees but judged by the
  Qualified Person to still retain structural
  integrity. Examples
• Single conks
• Small conks
• Saprot conks on one panel only associated with
  beetle strip attack
• Sounding with a handax on trees with buttrot
  indicates substantial sound wood remains.

8
Likely Failure Potential

• Cracks or structural defect associated with some
  decay on live trees.
• Wind shake
• Old burn damage with some decay on one panel

9
Likely Failure Potential

• Dead tops with some heart or saprot, usually with
  the bark starting to slough off.
• Species other than ponderosa pine and larch (both
  of which have Low FP).
• Minor or no resin infusion
• Includes defoliator-killed tops of grand fir and
  Douglas-fir
• Includes white pine with blister rust having a
  stem canker and dead top.
• older dead tops are usually less likely to fail
  than newly-killed tops.

10
Likely Failure Potential

• Dwarf mistletoe bole swellings with decay in lt1/2
  the bole diameter (rare in the Blue Mnts.)
• Brooms
• Large live brooms may have Likely FP
• Recent dead brooms that are mostly intact may
  have Likely FP

11
Likely Failure Potential

• Sunken cankers or deformations on the bole
  resulting from cankers, where more than ½ of the
  normal stem basal area exists at that point.
• -- includes mostly Atropellis canker of lodgepole
  pine and western gall rust canker of lodgepole
  and ponderosa pine.

12
Likely Failure Potential

• Structural deformities that are judged by the
  Qualified Person to have some but not excessive
  structural weakness on live trees.
• Forked tops and crotches associated with decay,
  cracks, splits, or callus ridges.
• Tight frost cracks have Low FP

13
Likely Failure Potential

• Dead trees that are still sound. Without
  signs and symptoms of extensive defect and decay.
  Rough guidelines are proposed for proportion of
  sound wood and number of years a tree is dead.
• See definition of sound.

14
Sound defined for dead trees

• Amount of bole or roots that are intact
• proposed sound if gt50 OR
• Number of years a tree is dead
• proposed sound if lt 3 years dead for true firs
  and hardwoods.
• proposed sound if lt 5 years dead for pines
  (lt16 dbh), Douglas-fir, spruce.
• proposed sound if lt 10 years dead for pines
  gt16 dbh.
• proposed sound if lt15 years dead for larch.

15
Likely Failure Potential

• Sufficiently fire-damaged trees, or all
  fire-killed trees that are still sound.
• Unless there is structural damage associated with
  root or bole wood consumption, failure potential
  will be Likely until sufficient decay and
  deterioration set in and trees are no longer
  sound.

16
Likely Failure Potential

• Hardwoods with saprot approaching ½ their
  diameter.
• Sound large branches on cottonwoods in the summer
  have Likely Failure Potential (not discussed in
  guidebook).