ISA Study Guide 2026
Everything you need to pass the ISA exam in one place: the exam format, every topic to study, real practice questions with explanations, flashcards, and full-length practice tests. Free, no sign-up needed.
📋 ISA Exam Format at a Glance
📚 ISA Topics to Study (40)
✍️ Sample ISA Questions & Answers
1. What is the primary purpose of establishing a drop zone during tree removal operations?
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.
2. What is the proper timing for fertilizing deciduous trees in most temperate climates?
Fertilization is most effective in late fall (after leaf drop, while soil is still warm) or early spring (before bud break). Late fall applications allow root absorption and storage; spring applications support the flush of new growth.
3. What is the proper hand signal for 'stop' during crane-assisted tree removal?
The standard hand signal for 'stop' in crane operations is extending one arm with a closed fist. This is part of the universally recognized crane hand signal system used across industries.
4. Which of these processes is essential for converting stored sugars into usable energy for a tree's growth, maintenance, and defense, and requires oxygen to occur?
Respiration is the metabolic process where trees break down sugars (produced during photosynthesis) to release energy for various life processes. This process requires oxygen, which is why soil aeration is critical for root health, as roots must also respire. Photosynthesis creates sugars, while respiration consumes them to produce energy.
5. Why is the concept of the 'critical root zone' important during construction near trees?
The critical root zone (CRZ) represents the minimum root area necessary for tree survival and structural stability. Damage within the CRZ from compaction, root cutting, or grade changes frequently leads to post-construction tree decline and potential failure.
6. What biosecurity measures should arborists take when pruning trees affected by or at risk for certain transmissible diseases?
When pruning trees with transmissible diseases (fire blight, Dutch elm disease, oak wilt), tools must be disinfected between cuts or between trees. Infected material should be disposed of properly (not chipped on site), and equipment should be cleaned to prevent spreading pathogens.