ISA Arboricultural Safe Work Practices 2 — Questions and Answers

Question 1: What is the minimum safe approach distance for a qualified line-clearance arborist working near energized conductors rated at 50 kV or below?

3 feet
10 feet (Correct answer)
15 feet
20 feet

Correct answer: 10 feet

ANSI Z133 specifies a minimum approach distance of 10 feet for qualified line-clearance arborists working near conductors energized at 50 kV or below.

The ANSI Z133 Safety Standard for Arboricultural Operations establishes minimum approach distances based on voltage levels. For conductors rated at 50 kV or below, the minimum approach distance is 10 feet for qualified line-clearance arborists. Unqualified workers must maintain even greater distances. These distances are critical for preventing electrocution, which remains one of the leading causes of fatalities in the tree care industry.

Question 2: Before starting any tree work, what is the first step in a job hazard analysis (JHA)?

Sharpening cutting tools
Identifying all potential hazards at the worksite (Correct answer)
Setting up traffic cones
Notifying the property owner

Correct answer: Identifying all potential hazards at the worksite

A job hazard analysis begins with identifying all potential hazards at the worksite, including overhead utilities, deadwood, ground conditions, and nearby structures.

A job hazard analysis (JHA) is a systematic approach to identifying and mitigating risks before work begins. The first step is always a thorough site assessment to identify all potential hazards such as overhead electrical lines, dead branches, unstable trees, underground utilities, uneven terrain, and proximity to buildings or people. Only after hazards are identified can appropriate controls and safety measures be implemented.

Question 3: What type of personal protective equipment is required when operating a chainsaw according to ANSI Z133?

Safety glasses only
Hard hat, eye protection, hearing protection, and chainsaw-resistant leg protection (Correct answer)
Gloves and steel-toed boots only
Reflective vest and hard hat

Correct answer: Hard hat, eye protection, hearing protection, and chainsaw-resistant leg protection

ANSI Z133 requires comprehensive PPE for chainsaw operation including hard hat, eye protection, hearing protection, and chainsaw-resistant leg protection (chaps or pants).

When operating a chainsaw, ANSI Z133 mandates a comprehensive PPE ensemble: a hard hat to protect against falling debris, eye protection (safety glasses or face shield) against wood chips, hearing protection due to high decibel levels, and chainsaw-resistant leg protection such as chaps or cut-resistant pants. Additional requirements include appropriate footwear and gloves. This multi-layered approach addresses the various injury risks associated with chainsaw operation.

Question 4: What is the proper procedure when a climber encounters an active bee or wasp nest while ascending a tree?

Continue climbing and spray the nest with insecticide
Descend slowly and carefully, then reassess the job plan (Correct answer)
Stay in position and call for a coworker to spray from the ground
Shake the branch to dislodge the nest

Correct answer: Descend slowly and carefully, then reassess the job plan

When encountering stinging insects, the safest action is to descend slowly to avoid agitating the colony, then reassess the situation and develop a plan that may include pest control treatment before resuming work.

Stinging insect encounters are a recognized hazard in arboricultural operations. The standard safety protocol is to carefully descend without sudden movements that might provoke a mass attack. Rapid movements, loud noises, or attempts to destroy the nest while in the tree can trigger a defensive response from the colony. After descending safely, the crew should reassess the job plan, which may include hiring a pest control professional to treat the nest before tree work resumes.

Question 5: How often should climbing ropes be inspected according to best safety practices?

Once a month
Before each use and at regular intervals during use (Correct answer)
Only when visible damage is noticed
At the beginning of each work week

Correct answer: Before each use and at regular intervals during use

Climbing ropes must be visually and tactilely inspected before each use and at regular intervals during the workday to detect any damage, wear, or contamination that could compromise safety.

Rope inspection is a critical safety practice in arboriculture. Ropes should be inspected before each use by running the entire working length through the hands to feel for flat spots, soft spots, lumps, or other irregularities. Visual inspection should check for cuts, abrasion, glazing, discoloration from chemicals, and UV degradation. Additionally, ropes should be re-inspected during the workday, especially after contact with sharp objects, rough bark, or if the rope has been loaded heavily. Any rope that fails inspection must be immediately retired from climbing use.

Question 6: What is the primary purpose of establishing a drop zone during tree removal operations?

To designate where equipment should be stored
To create a clear area where cut material can safely fall without striking people or property (Correct answer)
To mark the location for the chipper truck
To indicate the boundary of the property

Correct answer: To create a clear area where cut material can safely fall without striking people or property

A drop zone is a designated clear area below the work where cut branches and sections can fall safely, protecting ground workers and bystanders from being struck by falling material.

The drop zone is a fundamental safety concept in tree operations. It is a clearly defined area on the ground where cut material will land. All personnel must remain outside the drop zone during cutting operations. The zone must be free of people, valuable property, and obstacles. Communication between the climber and ground crew is essential — typically using verbal signals before any cut is made. Ground workers must acknowledge the warning before the climber proceeds. Proper drop zone management prevents crush injuries, which are among the most serious hazards in tree work.

ISA Arboricultural Safe Work Practices 2

What is the minimum safe approach distance for a qualified line-clearance arborist working near energized conductors rated at 50 kV or below?