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Welcome to the PassArborist Blog: ISA Arborist Exam Study Notes
What the PassArborist blog will cover, the ISA Certified Arborist exam at a glance, and how to use these notes alongside the app and the free practice test.
By PassArborist Editorial Team
Key takeaways
- This blog is where we publish study plans, domain deep dives and test-day strategy for the ISA Certified Arborist® exam.
- The exam has 200 multiple-choice questions in 3.5 hours, spread across 10 domains, and the current passing score is 76 percent.
- Safe Work Practices (15%) and Pruning (14%) carry the most weight; Urban Forestry (6%) and Soil Management (7%) the least.
- Every exam fact here comes from ISA’s Certified Arborist Program Guide, and we date anything that can change.
Welcome to the PassArborist blog. We build PassArborist, a study app for arborists preparing for the ISA Certified Arborist® exam, and this is where we will publish what we learn about the exam and how to prepare for it.
Most candidates come to the exam with years of field experience. You already know how to make a good pruning cut or spot a hazard. What the exam adds is vocabulary, standards and the “why” behind the work, asked in a multiple-choice format. These notes are written to close that gap.
What this blog will cover
- Study plans: how to split your time across the 10 domains based on their weight on the exam, for a few weeks or a few months of preparation.
- Domain deep dives: one topic at a time, from CODIT and the branch bark ridge to tree protection zones and minimum approach distances.
- Practice questions with explanations: exam-style questions worked through step by step, so you see how the answer is reached.
- Test-day strategy: applying, booking a Pearson VUE seat, pacing 200 questions in 210 minutes and what to do with the ones you are unsure about.
Posts go up on a regular schedule. New ones appear on the blog page and in the RSS feed.
The ISA Certified Arborist exam at a glance
| Credential | ISA Certified Arborist® |
| Awarded by | International Society of Arboriculture (ISA) |
| Questions | 200 multiple-choice, four options each |
| Time | 3.5 hours (210 minutes) |
| Passing score | 76 percent |
| Eligibility | 3 years of full-time arboriculture experience, or a qualifying degree or training program plus experience |
| Delivery | Computer-based at a Pearson VUE test center, or an exam run by an ISA Certification Partner |
| Fees | Application $40 for ISA members, $50 for others; exam enrollment $295 for members, $369 for others |
| Valid for | 3 years; renew with 30 continuing education units (CEUs) or by retaking the exam |
Source: ISA Certified Arborist Program Guide, revised August 2025. ISA changes fees and details from time to time, so check the official ISA page before you apply.
The 10 exam domains
ISA publishes the share of exam questions that comes from each domain. On a 200-question exam, each percentage point is about two questions.
| Domain | Share of exam | About |
|---|---|---|
| Safe Work Practices | 15% | 30 questions |
| Pruning | 14% | 28 questions |
| Tree Biology | 11% | 22 questions |
| Tree Risk | 11% | 22 questions |
| Tree Identification and Selection | 9% | 18 questions |
| Installation and Establishment | 9% | 18 questions |
| Diagnosis and Treatment | 9% | 18 questions |
| Trees and Construction | 9% | 18 questions |
| Soil Management | 7% | 14 questions |
| Urban Forestry | 6% | 12 questions |
The top four domains make up just over half of the exam. That is a useful starting point for planning, and our first study plan will build on it.
How to use these notes
Reading helps, but the exam rewards answering questions. Three ways to put these notes to work:
- Check your baseline. Take the free 20-question arborist practice test. It samples every domain in roughly exam proportions and explains each answer.
- Read the deep dive for your weakest domain once it is published, then practice that domain on its own.
- Practice daily in the app. PassArborist has practice questions for every domain, full 200-question mock exams and an AI tutor that explains the reasoning behind each answer. Short daily sessions add up.
Frequently asked questions
Is PassArborist affiliated with ISA?
No. PassArborist is an independent study tool. It is not affiliated with, sponsored or endorsed by the International Society of Arboriculture. ISA Certified Arborist® is a registered certification mark of ISA.
Where do the exam facts on this blog come from?
From ISA’s own publications, mainly the Certified Arborist Program Guide (revised August 2025). We link the source next to each fact and note the date, because fees and policies change.
Are the practice questions real ISA exam questions?
No. ISA does not release live exam questions. Our questions are original and exam-style, written to match the topics in ISA’s exam outline, and each comes with a written explanation.
Can I suggest a topic?
Yes. Email us with the topic or question you are stuck on, and we will consider it for a future post.
Written by
PassArborist Editorial Team
The team behind PassArborist, the ISA arborist exam prep app. Questions or corrections? Contact us.