Certified Arborist Test Cheat Sheet 2026

The 30 highest-yield Certified Arborist Test facts, distilled from real exam questions. Print it, save it as a PDF, or study it here — free, no sign-up.

1. Which arrangement, with a petiolule for each leaflet, places the leaflets of a compound leaf along a single stem? → Pinnate
2. Which leaf type is characteristic of maple trees? → Simple palmate
3. How deep of a notch should be made while felling a tree in general? → No more than one-third of the diameter of the tree
4. Which type of conductor poses the greatest electrical hazard to line clearance arborists? → Bare primary distribution conductors
5. Which soil amendment is most universally recommended when backfilling a tree planting hole? → The original native soil without amendments
6. What is a highly fertile region around growing roots? → Rhizosphere
7. Photosynthesis primarily occurs in which part of the tree? → Leaves
8. What is the purpose of staking a newly planted tree? → To provide temporary support until roots establish, allowing some trunk movement
9. During structural pruning, what determines the height of the lowest permanent branch? → It is determined by both the location and function.
10. Which soil condition is most commonly cited as the primary limiting factor for urban tree establishment and long-term survival? → Soil compaction reducing pore space, aeration, and root penetration
11. Which kind of nursery stock is less likely to have roots girdle when planted? → Bare root
12. An irregular plant growth that is frequently found in the leaf tissue is also known as: → Galls
13. What is the best long-term strategy for reducing utility line clearance maintenance costs? → Planting low-growing compatible species under and adjacent to utility lines
14. The primary objective of insect pest control in the Plant Health Care paradigm is → suppression.
15. Which of these describes a hybrid? → Nepenthes x hookeriana
16. How does auxin (IAA) produced in apical buds influence lateral bud development? → It suppresses lateral bud growth, a phenomenon called apical dominance
17. What term is used to describe insects that carry plant pathogens? → Vectors
18. Which macronutrient is primarily responsible for leafy growth in trees? → Nitrogen
19. What tool is best for cutting branches over 2 inches in diameter? → Pruning saw
20. How can an arborist help mitigate damage after roots have been cut during construction? → Clean-cut the damaged roots, water deeply, mulch the root zone, and monitor for stress
21. What is the term used to describe a broad planting of the same species over a wide area? → Monoculture
22. In tree physiology, what is 'girdling' and what is its primary consequence? → Disruption of the phloem causing starvation of roots
23. What cable material does the ISA specify as the standard for static high cabling installations in trees? → Galvanized Extra High Strength (EHS) wire rope
24. A client in USDA Hardiness Zone 5b wants to plant a tree that is rated for Zone 7a. What is the most likely outcome if this tree is planted? → The tree is likely to suffer from winter injury or die.
25. Which of these pruning methods does the arborist use to reduce the branch to a comparatively weak point? → Heading cut
26. Which condition is an abiotic disorder? → Girdling roots
27. What is the role of lenticels on tree bark? → Allowing gas exchange between internal tissues and the atmosphere
28. What does integrated pest management aim to achieve? → For maintaining pest damage at a tolerable level.
29. Frass, often found in trees, is a combination of insect waste and what other substance? → Sawdust
30. What is the ideal mulch depth around a newly planted tree? → 2-4 inches