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Hazard Tree – Felling Safety Tips

 

Felling a hazard tree requires accurate risk assessment and complexity analysis, and demands the sawyer’s full situational awareness. In all cases, remember to establish and maintain a secure felling area.

Do not bypass hazard trees without taking some action such as felling or establishing a No-Work-Zone.

Degree of hazard varies with tree size, species, and type/location of defect:

  • Stem defects resulting in tree failure, i.e., collapse.
  • Weakened sapwood resulting in loss of control when falling trees & limits solid wood for wedging. 
  • Overhead hazards, i.e., dead or hanging limbs falling on the faller.

Line art of a snag tree with bare branches

Indicators of potential felling hazards:

Dead Limbs: limbs of all sizes and species with decay evident cracking, or loose, hung-up limbs. Avoid working under overhead hazards.

Witches Broom: caused by mistletoe infection, limbs can grow very large and heavy (200+ lbs).

Split Trunk: cracked trunk from frost, lightning, or wind. Visible evidence of advanced decay indicates serious weakness where the tree could fail.

Stem Damage: caused by windfall, scarring, fire, machine, and animal damage, as well as heart rot diseases.

Thick Sloughing Bark or Sloughing Sapwood: usually found on dead trees. Loose bark on Douglas fir or loose sapwood on wind snapped cedars can dislodge during falling.

Butt and Stem Cankers: usually found on deciduous trees but can occur on Douglas fir and pine. The infected areas weaken the stem.

Fungal Fruiting Bodies or Conks: found on stems it may indicate massive interior rot 1-2 yards above and below conk. Excessive resinosis (resin flow) also indicates heart or root diseases.

Heavy Tree Lean: may be caused by damaged roots or lifting root mats, shallow or wet soils. In some cases, the tree may have corrected itself which can be determined by looking for corrected top growth.

Root Condition: look for any ground cracks around the base of the tree, signs of decay or fungal conks on the roots.

Cat Face: look for enough solid wood to construct an effective undercut and back cut.

 

Category
Felling Safety
References
Hazard Tree and Tree Felling Subcommittee

Last Modified / Reviewed:


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Questions?  Please contact:
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Air Operations Summary (ICS 220 WF)

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Questions?  Please contact:
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NWCG Firing Boss, Single Resource Position Page

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NWCG Position Task Book for Firing Boss, Single Resource (FIRB), PMS 311-105

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Questions?  Please contact:
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Any changes to qualification pathways will take effect with the next update of the NWCG Standards for Wildland Fire Position Qualifications, PMS 310-1.

References:

NWCG Incident Position Standards for Helicopter Crewmember, PMS 350-22

NWCG Incident Position Standards for Helicopter Crewmember, PMS 350-22

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References:

NWCG Standards for Fire Unmanned Aircraft Systems Operations, PMS 515

NWCG National Interagency Aviation Committee