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Hazard Tree – Identification

hazard-tree-identification-graphic.pngSome common tree deficiencies which contribute to potential felling hazards:

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

Weak Tops: split/schoolmarm tops that could have weakened unions, fire weakened tops, rotten or dead tops.

Witches Broom: caused by mistletoe infection, limbs can grow very large and heavy (200+ lbs). Can contribute to uneven weight distribution.

Split Trunk: cracked trunk from frost, lightning, or wind. Visible evidence of advanced decay indicates serious weakness where the tree could fail. May increase wood fiber tension contributing to barber chair potential.

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

Cat Face:  look for enough solid wood to construct an effective undercut and back cut. Complexity increases when desired felling direction is different than that of the cat face.

Thick Sloughing Bark: usually found on dead trees. Loose bark, particularly on Douglas firs, can injure sawyers.

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 may indicate massive interior rot. Excessive resinosis (resin flow) also indicates heart or root diseases.

Heavy Tree Lean: look for any ground cracks around the base of the tree. 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: weakened roots may reduce felling control. Signs of decay or fungal conks on the roots, or fire weakened roots.

Species Consideration: consult local experts for species deficiencies particular to local areas. A good habit is to observe overall tree stand health wherever you’re working.

Felling a hazard tree requires accurate risk assessment and complexity analysis and demands the sawyer’s full situational awareness. Do not bypass hazard trees without taking some action such as felling or establishing a No-Work-Zone.

Discuss indicators of tree defects specific to your local area.

 

Category
Felling Safety
References
Hazard Tree Identification Field Guide

6MFS Suggestion Form


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Date: Sept 11, 2025
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The S-219, Firing Operations (Blended) course is now available on the Wildland Fire Learning Portal. Developed through the Incident Performance and Training Modernization (IPTM) effort, this training supports individuals working towards Firing Boss, Single Resource (FIRB) incident qualifications.

This blended course combines online and instructor-led training to provide students with the knowledge and skills required to perform the duties of the FIRB, as described in the NWCG Incident Position Standards for Firing Boss, Single Resource, PMS 350-105.

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S-219, Firing Operations (Blended)

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Date: Aug 15, 2025
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NWCG is excited to announce that the S-290, Intermediate Wildland Fire Behavior (Blended) training is now available on the Wildland Fire Learning Portal. S-290 (Blended) training combines online training and instructor-led training components that support individuals working towards any Single Resource Boss or Fire Effects Monitor incident qualifications.

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