CATS - Certified Arborist Tree Service of Albuquerque Cabling, Bracing, and Support Questions and Answers 1 — Questions and Answers
Question 1: An arborist is installing a static support cable between two large codominant stems. According to ANSI A300 (Part 3) standards, what is the generally accepted placement height for the cable?
- At least two-thirds of the distance from the weak union to the tops of the stems being supported. (Correct answer)
- Exactly halfway between the ground and the weak union.
- One-quarter of the distance from the weak union to the tops of the stems.
- As low as possible in the union to maximize pulling force.
Correct answer: At least two-thirds of the distance from the weak union to the tops of the stems being supported.
ANSI A300 Part 3 standards specify that cables should be installed at least two-thirds of the distance from the defect (the weak union) to the tops of the limbs being supported. This placement provides the best leverage to reduce movement and stress on the union.
Question 2: Which of the following is the PRIMARY purpose for installing a threaded steel brace rod through a split tree trunk?
- To pull the two sides of the split tightly back together.
- To provide rigid support to limit further twisting or spreading of the split. (Correct answer)
- To act as a conduit for systemic fungicides to reach the damaged area.
- To encourage the development of stronger reaction wood within the split.
Correct answer: To provide rigid support to limit further twisting or spreading of the split.
The main function of a brace rod is to provide rigid, stationary support to a weak or split union. It is not intended to pull the split closed, which can cause further damage, but rather to prevent the existing damage from worsening by limiting movement.
Question 3: A client requests a support system that allows for natural tree movement to encourage reaction wood development, while still providing support during high-wind events. Which type of system best fits this description?
- A static system using Extra High-Strength steel cable.
- A rigid system using multiple threaded steel rods.
- A propping system with a solid, unmoving post.
- A dynamic system using synthetic fiber rope. (Correct answer)
Correct answer: A dynamic system using synthetic fiber rope.
Dynamic support systems use synthetic, rope-like materials that allow the tree to sway and move naturally under normal conditions, which helps it build strength. They only become taut and provide support when movement exceeds a certain threshold, such as during a storm. Static steel cables are designed to minimize movement at all times.
Question 4: When attaching a support cable to a limb that is greater than 10 inches in diameter, which of the following anchor hardware is generally required by industry best practices to ensure a secure attachment?
- A drop-forged J-lag screw.
- A through-bolt with a washer and nut. (Correct answer)
- A heavy-duty eye screw.
- A wire-stop termination wrapped around the limb.
Correct answer: A through-bolt with a washer and nut.
For larger limbs (generally those over 8-10 inches in diameter), through-bolts are required because they distribute the load through the entire limb and are much more secure. Lag-threaded hardware, like J-lags, relies only on the holding power of the wood threads and is not considered sufficient for larger, heavier limbs.
Question 5: During a routine inspection of a mature tree with an older cabling system, which of the following findings would require the MOST immediate corrective action?
- The cable has a slight, graceful sag between the two anchor points.
- A thimble is missing from the eye splice, causing the cable to bend sharply over the anchor. (Correct answer)
- The tree has grown approximately one inch of wood over the edges of the anchor washer.
- The cable shows minor surface rust but no broken strands.
Correct answer: A thimble is missing from the eye splice, causing the cable to bend sharply over the anchor.
The thimble protects the cable from a sharp bend and excessive wear at the termination point. Without it, the cable can fatigue and fail at a load well below its rated strength, creating a significant hazard. The other conditions are less critical; slight sag is often intentional, bark growth over hardware is expected, and minor surface rust is not an immediate failure risk.
Question 6: An arborist determines that a tree with codominant stems requires both cabling in the upper crown and bracing through the weak union. According to best management practices, what is the proper sequence for this installation?
- Install the brace rod first, then install the cable.
- The order of installation does not matter.
- Prune to reduce end-weight, install the cable, then install the brace rod. (Correct answer)
- Install both the cable and brace rod simultaneously.
Correct answer: Prune to reduce end-weight, install the cable, then install the brace rod.
The standard and safest procedure is to first perform any necessary pruning to reduce weight on the limbs. Next, the cable should be installed in the upper crown to provide support from above. Finally, with the union supported by the cable, the brace rod can be safely installed through the crotch.
CATS - Certified Arborist Tree Service of Albuquerque Cabling, Bracing, and Support Questions and Answers 1
An arborist is installing a static support cable between two large codominant stems.
According to ANSI A300 (Part 3) standards, what is the generally accepted placement height for the cable?