Visually inspect each tree completely from the ground for potential hazards before you climb or begin work. Examine all elements of the tree, from the roots to the branches. A careful examination of the climbing and work site is also necessary, as most property damage results from neglecting this part of the preclimb inspection.

Tree foliage will often obstruct the view of tree hazards hidden within the canopy. The use of binoculars will assist in locating them. As you climb and perform work aloft, continue to perform a visual inspection of the tree, watching for problems that were not visible from the ground. In addition, be attentive to sounds that could indicate a potential hazard, such as the buzzing of hornets and bees, or any other animal noises.

Use this checklist to help locate the tree and site hazards. Identify the spot most suitable for rope installation, mindful of these known hazards.

Root Zone

  • Mushrooms present at the base of tree (sign of root rot)
  • Cracks near root flare
  • Lack of root flare
  • Soil mounding (tree falling)


  • Mushrooms and conks
  • Cracks and cavities (use a rubber mallet for sounding the trunk)
  • Vines (can be poisonous and often obscure other hazards)
  • Loose bark
  • Swellings or depressions

Check the canopy and drop zone for electrical conductors. Maintain minimum approach distances at all times.

Photo: ISA

Tree Crown

  • Hangers (lodged branches)
  • Dead and weak branches
  • Weak branch attachments
  • Cracks/splits along stem, branch or where branches are attached
  • Stinging insects (look and listen)
  • Animals (look and listen) – sound the trunk with mallet to arouse activity
  • Electrical conductors (often concealed by foliage and therefore are not always readily visible)

Storm-related Situations

  • Tree parts under points of pressure and tension
  • Lodged branches – be particularly alert for hangers found near or blocking the climbing route
  • Ice, snow or wet limbs – create slippery climbing conditions and hide tree defects

Climbing and Work Site

  • Look for potential targets, obstructions and hazards, such as:
  • Structures (e.g., buildings, decks)
  • Vehicles (parked or moving)
  • Sidewalks and driveways
  • Septic system and drain fields
  • Lawn ornaments, furniture, clothes lines, play areas, bird feeders and landscape lighting
  • Young trees and shrubs, flower beds and other landscape items
  • Satellite dishes and antennas
  • Electrical hazards
  • Wet and muddy areas
  • Poisonous plants
  • Extreme slopes
  • People in the area (such as homeowners or bystanders)

Editor’s note: This article is excerpted from “The Tree Climber’s Companion” (second edition) by Jeff Jepson.