Certified Arborist Test Cabling Bracing and Support Systems 1 — Questions and Answers
Question 1: What cable material does the ISA specify as the standard for static high cabling installations in trees?
- Galvanized Extra High Strength (EHS) wire rope (Correct answer)
- Synthetic polyester braided rope
- Stainless steel aircraft cable
- Kevlar fiber cord
Correct answer: Galvanized Extra High Strength (EHS) wire rope
ISA Best Management Practices specify Galvanized Extra High Strength (EHS) wire rope for static cabling systems because of its superior tensile strength, corrosion resistance, and long service life compared to alternatives.
Question 2: According to ISA Best Management Practices, how frequently should installed cabling and bracing systems be inspected?
- Every five years as part of a long-term care plan
- Annually and after any significant storm or loading event (Correct answer)
- Only when visible sagging or hardware corrosion is observed
- Once every ten years unless the tree shows decline
Correct answer: Annually and after any significant storm or loading event
ISA guidelines recommend annual inspections of cabling and bracing systems, with additional inspections following major storms, because hardware can corrode, cables can lose tension, and the tree's growth can alter load dynamics over time.
Question 3: When a cabling system is installed on a tree with co-dominant stems, what complementary pruning practice is most commonly recommended to reduce stress on the cable?
- Removing all lateral branches from both stems below the cable
- Performing crown reduction on the supported stem or limb (Correct answer)
- Applying wound sealant to the included bark union
- Raising the crown by removing lower scaffold branches
Correct answer: Performing crown reduction on the supported stem or limb
Crown reduction of the supported stem decreases its weight and wind-sail effect, directly reducing the dynamic load transferred to the cable and anchoring hardware during storm events.
Question 4: What is the primary structural advantage of a triangulated (three-point or multi-point) cabling system over a simple two-point system?
- It requires less total cable length, reducing installation cost
- It distributes loads in multiple directions, resisting movement from any compass point (Correct answer)
- It eliminates the need for periodic hardware re-tensioning
- It is the only system approved for trees under utility lines
Correct answer: It distributes loads in multiple directions, resisting movement from any compass point
A triangulated system ties three or more stems together so that lateral loads from any direction are shared across multiple cable runs, whereas a two-point system only resists movement in the plane of the single cable.
Question 5: What is the purpose of a turnbuckle included in a static cabling system?
- To allow controlled dynamic movement that mimics a flexible cabling system
- To join two separate cable segments of different diameters
- To adjust and set cable tension during and after installation (Correct answer)
- To prevent galvanic corrosion where cable meets eyebolt hardware
Correct answer: To adjust and set cable tension during and after installation
A turnbuckle provides a means to tension the cable to the specified tautness at installation and to re-tension it during subsequent inspections as the tree grows and hardware seats into the wood.
Question 6: Which condition most clearly indicates that a threaded brace rod is needed in addition to, or instead of, a cable alone?
- A tree exhibiting a gradual lean away from the prevailing wind direction
- A longitudinal crack or split in the stem that allows the two sides to move apart laterally (Correct answer)
- A tree with more than five co-dominant leaders in the upper crown
- An included bark union located higher than two-thirds of the total tree height
Correct answer: A longitudinal crack or split in the stem that allows the two sides to move apart laterally
Brace rods are designed to resist the splitting or spreading of a cracked stem by passing a threaded rod through both sides and securing it with washers and nuts; cables address vertical or lateral tip movement but cannot hold a splitting stem together.
Certified Arborist Test Cabling Bracing and Support Systems 1
What cable material does the ISA specify as the standard for static high cabling installations in trees?