Title: HAZARD TREE SAFETY ASSESSMENT
1HAZARD TREE SAFETY ASSESSMENT
Version 03-20-2006
2 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.
3Tree Class ComparisonLive Dead Conifers 1 2 3
4 5 6 7 8 9
4 TREE Class Comparison
Hardwoods 2 3 4 5 6
5 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.
6Generalized Tree Defects or Indicators Which
Influence Tree FailureGeneralized Tree
Defects or Indicators Which Influence Tree
FailureGeneralized Tree Defects or
Indicators Which Influence Tree Failure
7Generalized Tree Defects or Indicators Which
Influence Tree FailureGeneralized Tree
Defects or Indicators Which Influence Tree
FailureASSESSING TREE LEAN
8Generalized Tree Defects or Indicators Which
Influence Tree FailureGeneralized Tree
Defects or Indicators Which Influence Tree
FailureASSESSING ROOT CONDITION
9Generalized Tree Defects or Indicators Which
Influence Tree FailureGeneralized Tree
Defects or Indicators Which Influence Tree
Failure4 Significant Hazard Indicators
10Generalized 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.
11 No-Work Zone (NWZ) Sound tree, no lean,
hazardous top, flat ground
12 No-Work Zone (NWZ) Sound tree with
lean, hazardous top, on slope
13 No-Work Zone (NWZ) Unsound or hazardous
tree, no lean, flat ground
14 No-Work Zone (NWZ) Sound tree
with lean, hazardous top, on slope
15 No-Work Zone (NWZ) Deciduous,
sound tree, no lean, defective branches
16Delineating Larger no-Work Zone
AREASDelineating Larger no-Work Zone
AREASDelineating Larger No-Work Safe Zone
Areas
17Delineating Larger no-Work Zone
AREASDelineating Larger no-Work Zone
AREASHazard Trees Along Roadsides
18Delineating 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
19Delineating Larger no-Work Zone
AREASDelineating Larger no-Work Zone
AREASHAZARD TREE SAFETY ASSESSMENT