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 (56)
✍️ 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. Nitrogen deficiency in trees typically presents as:
Nitrogen is mobile in the plant, so deficiency symptoms appear first on older leaves as nitrogen is redirected to new growth.
3. 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.
4. 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.
5. 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.
6. What is the recommended depth for applying organic mulch around trees?
A 2–4 inch mulch layer conserves moisture and moderates temperature without creating anaerobic conditions at the root flare.