HAZARD TREE SAFETY ASSESSMENT

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HAZARD TREE SAFETY ASSESSMENT
Version 03-20-2006
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A HAZARD TREE

• ...is any tree (regardless of its size) that is
  hazardous to people or property because of
• location or lean
• physical damage
• overhead hazards
• deterioration of limbs, stem or root system
• a combination of above.

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Tree Class ComparisonLive Dead Conifers 1 2 3
4 5 6 7 8 9
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TREE Class Comparison
Hardwoods 2 3 4 5 6
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RISK HAZARD x EXPOSURE

• The procedures for determining whether a tree is
  dangerous to workers under various levels of
  disturbance, and the appropriate steps and safety
  procedures for mitigating the hazard.

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Generalized Tree Defects or Indicators Which
Influence Tree FailureGeneralized Tree
Defects or Indicators Which Influence Tree
FailureGeneralized Tree Defects or
Indicators Which Influence Tree Failure
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Generalized Tree Defects or Indicators Which
Influence Tree FailureGeneralized Tree
Defects or Indicators Which Influence Tree
FailureASSESSING TREE LEAN
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Generalized Tree Defects or Indicators Which
Influence Tree FailureGeneralized Tree
Defects or Indicators Which Influence Tree
FailureASSESSING ROOT CONDITION
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Generalized Tree Defects or Indicators Which
Influence Tree FailureGeneralized Tree
Defects or Indicators Which Influence Tree
Failure4 Significant Hazard Indicators
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Generalized Tree Defects or Indicators Which
Influence Tree FailureGeneralized Tree
Defects or Indicators Which Influence Tree
Failure No-Work Zone (NWZ)

• The size of NWZs is 1.5 times the defect length.
  This length can be modified (larger or smaller)
  depending on the site-specific conditions, such
  as slope or surrounding tree size and condition.
  The NWZ must be big enough to accommodate the
  hazard.

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No-Work Zone (NWZ) Sound tree, no lean,
hazardous top, flat ground
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No-Work Zone (NWZ) Sound tree with
lean, hazardous top, on slope
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No-Work Zone (NWZ) Unsound or hazardous
tree, no lean, flat ground
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No-Work Zone (NWZ) Sound tree
with lean, hazardous top, on slope
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No-Work Zone (NWZ) Deciduous,
sound tree, no lean, defective branches
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Delineating Larger no-Work Zone
AREASDelineating Larger no-Work Zone
AREASDelineating Larger No-Work Safe Zone
Areas
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Delineating Larger no-Work Zone
AREASDelineating Larger no-Work Zone
AREASHazard Trees Along Roadsides
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Delineating Larger no-Work Zone
AREASDelineating Larger no-Work Zone
AREAS SWAMPER, LOOKOUTS AND
OBSERVERS

• This section will be updated when staff work is
  completed by June, 2006

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Delineating Larger no-Work Zone
AREASDelineating Larger no-Work Zone
AREASHAZARD TREE SAFETY ASSESSMENT