Key Takeaways
ISA stands for International Society of Arboriculture
Certification shows real training, testing, and experience
Garrison Mull, owner of Dungrove Tree Service, is ISA-certified
ISA-certified arborists give safer, more accurate, and better long-term care
ISA stands for the International Society of Arboriculture. It’s one of the most respected organizations in the tree care world. When someone says they’re an ISA-certified arborist, it means they’ve passed a real test, have verified experience, and keep up with ongoing education.
Garrison Mull, the owner of Dungrove Tree Service, is ISA-certified. That means when he visits your property, you’re getting advice and service from someone who’s met the standards of a global tree care organization—not just someone who owns a chainsaw.
What Does ISA Certification Require?
To become ISA certified, you need to:
Have ExperienceMost candidates need at least three years of full-time work in tree care or a combination of work and education.
Pass a Real ExamThe ISA test covers tree biology, diagnosis, pruning, soil science, tree risk, safety, and more. It’s not something you pass without study and real-world know-how.
Agree to a Code of EthicsCertified arborists must follow standards for safety, transparency, and honest recommendations.
Why Hiring an ISA-Certified Arborist Helps You
There are lots of tree services out there. Some are great. Some… aren’t.
When you work with someone who’s ISA certified—like Garrison—you get:
Advice based on tree science, not guesswork
Safer pruning and removal techniques
Help spotting problems before they get worse
Knowledge of local tree diseases and how to prevent them
Clear communication and trustworthy recommendations
It’s not just about removing trees. It’s about knowing when to remove them—and when not to.
What Makes Garrison Different
Garrison Mull isn’t just the guy quoting the job—he’s the one walking the yard, climbing the tree, and making sure it’s done right. He got certified through ISA so he could give better advice and back it up with real training.
So when he tells you a tree is safe to leave alone or needs pruning to avoid damage in a storm, he’s not guessing. He’s relying on a strong knowledge base and years of experience.
Questions People Ask
Does ISA certification mean a company is better?Not always, but it’s a good sign. It means at least one person has proven knowledge and follows industry best practices.
Can anyone say they’re an arborist?In most places, yes. That’s why ISA certification matters—it’s a verified credential that shows training and testing.
What does the ISA do?The International Society of Arboriculture is a nonprofit group that promotes tree health, safety, and science-based care around the world.
Want a Certified Arborist to Check Your Trees?
Call or message Dungrove today. Garrison Mull—our ISA-certified owner—will come out, look at your trees, and give you honest feedback.
Free quotes. No pressure. Just expert help from someone who’s certified to know what your tree needs.
