What Is an ISA Certified Arborist — And Why It Matters for Your Trees

The Difference Between a Tree Service and a Certified Arborist

When a large branch falls, or a tree starts leaning toward your home after a storm, most homeowners reach for their phone and search for the nearest tree service. But not all tree services are the same — and the difference between a random crew with a chainsaw and an ISA Certified Arborist can mean the difference between a tree that recovers and one that slowly dies over the next five years.

At Tree Care Enterprises, we’ve spent 47 years serving the Rockford, IL and Lake Geneva, WI communities, and we have more than eight ISA Certified Arborists on staff. We’re also TCIA Accredited and one of only 20 tree care companies in the country to earn national recognition from TCI Magazine.

What Is an ISA Certified Arborist?

The International Society of Arboriculture (ISA) is the gold standard credentialing body in professional tree care. An ISA Certified Arborist is someone who has accumulated a minimum of three years of full-time hands-on experience in professional tree care, passed a comprehensive written examination covering tree biology, diagnosis, pruning, soil science, installation, and safety, and committed to ongoing continuing education to maintain the credential — earning CEUs every three years.

What Does an Arborist Actually Do?

Arborists are trained specialists in the cultivation, management, and study of individual trees, shrubs, vines, and other woody plants. A certified arborist can diagnose tree diseases and pest infestations — including Emerald Ash Borer, Bronze Birch Borer, Dutch Elm Disease, Oak Wilt, and dozens of fungal pathogens — and prescribe appropriate treatments. They assess structural risk, perform proper pruning using cuts that promote healing, guide planting decisions, and provide tree preservation services to protect trees during construction or stress events.

Why Does the ISA Certification Matter?

Here’s a hard truth: in most states including Illinois, anyone with a truck and a chainsaw can legally call themselves a tree service. There’s no required licensing for basic tree work. ISA certification changes that. Improper cuts create wounds that trees cannot compartmentalize, becoming entry points for wood-decaying fungi. Tree topping — cutting the main leader back to stubs — creates weakly attached regrowth and typically kills the tree within a decade. Certified arborists don’t top trees, and they diagnose problems correctly the first time.

ISA Certification vs. TCIA Accreditation

ISA Certification is an individual credential earned through personal testing and continuing education. TCIA Accreditation is a company-level credential: the Tree Care Industry Association evaluates the entire business — safety programs, business practices, insurance, employee training, and equipment maintenance. Fewer than 10% of tree care companies in the United States are TCIA Accredited. Tree Care Enterprises has held TCIA Accreditation since 2007.

Questions to Ask Before Hiring Any Tree Service

Ask for the arborist’s ISA certification number — ISA provides a public lookup at treesaregood.org so you can verify it yourself. Ask for a certificate of insurance covering both general liability and workers’ compensation. Ask whether the company follows ANSI A300 standards, the industry standard for tree care practices. Always get scope and pricing in writing before work begins.

When Should You Call a Certified Arborist?

Call a certified arborist when a tree shows visible signs of disease or pest infestation, when a tree is leaning or you notice a sudden change in its lean, when large branches are dead or cracked, when you’re planning construction near a tree’s root zone, when you want to prune large or mature trees, or when you’re unsure whether a tree should be removed or can be saved.

Serving Rockford, IL and Lake Geneva, WI Since 1978

Tree Care Enterprises has been providing ISA Certified Arborist services throughout the Stateline region for over 47 years. Our team of more than eight certified arborists is available to assess, treat, prune, preserve, and safely remove trees of any size. Call us at 815-965-5757 or contact us online for a free estimate.