Cabling Bracing and Support Systems Flashcards
6 cards from real Certified Arborist Test practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 6 Cabling Bracing and Support Systems flashcards as text
What is the difference between a static cabling system and a dynamic cabling system in tree support?
Answer: Static systems use rigid steel cables that prevent movement at the defined limit; dynamic systems use flexible, elastic synthetic materials that allow some movement and energy absorption before reaching maximum resistance
Static systems use inelastic steel cables that immediately resist movement once taut, preventing motion beyond the cable length. Dynamic systems use elastic synthetic rope or cable that stretches under load, absorbing energy and allowing some movement before maximum resistance is reached, potentially reducing shock load at anchor points.
What hardware is used to anchor cabling systems within tree stems, and what are the minimum specifications for its installation?
Answer: Threaded rod (thru-bolts) for cabling anchors, typically minimum 1/2 inch diameter through-bolts for cables, installed through the full stem diameter with plates and nuts on both sides, or lag screws of appropriate diameter and penetration depth
Standard cabling hardware uses threaded through-bolts (typically 1/2 inch diameter minimum) installed through the full diameter of the stem with washers and nuts on both faces for cabling loads, distributing forces across the full stem cross-section. Lag screw anchors are also used following minimum penetration depth specifications.
When is bracing (rod installation) used rather than or in addition to cabling, and what structural problem does it address?
Answer: Bracing addresses split or cracked unions and co-dominant stems with existing or incipient cracks, providing rigid resistance to spreading forces within a structural defect zone that cables above cannot adequately control
Bracing rods are installed through co-dominant stems at or near existing cracks or split unions to prevent spreading and further splitting. Cables above control union separation at a distance, but bracing provides rigid stabilization directly within the defect zone — the two systems are frequently used together.
What is the recommended cable installation height for a two-point high cabling system, and how is it determined?
Answer: Cables are typically installed at two-thirds the distance from the defective union to the end of the structural part being cabled, to maximize the mechanical advantage while leaving adequate anchoring length above
Standard cable installation height is two-thirds of the distance from the union to the end of the branch or stem being cabled. This position maximizes the cable's ability to resist union separation (long lever arm against the defect) while leaving sufficient wood above the hardware to hold the anchor securely.
How often should cabling and bracing systems be inspected, and what does inspection involve?
Answer: ANSI A300 Part 3 recommends annual inspection of all cabling and bracing systems by a qualified arborist, assessing hardware condition, cable tension and integrity, wood condition around anchors, and changes in the underlying structural defect
ANSI A300 Part 3 recommends annual inspection of installed cabling and bracing systems. Inspection assesses hardware for corrosion, loosening, or failure; cable condition (fraying, corrosion, elongation); wood condition around anchors (decay, growth changes); and the current status of the defect being mitigated — including whether the system remains adequate as the tree changes.
What factors determine whether a tree with a structural defect should be cabled or removed?
Answer: The decision depends on risk assessment results, the tree's intrinsic value (historical, ecological, aesthetic), the likelihood that the cabling system will successfully mitigate the risk, the owner's risk tolerance, and whether the risk can be reduced to an acceptable level through supplemental support
The decision to cable versus remove is a risk management judgment integrating risk assessment results (failure probability, target, consequence), the tree's value, the technical feasibility of adequate risk mitigation through cabling, the owner's informed risk tolerance, and whether the system can achieve an acceptable risk level — there is no single rule applying to all situations.