BALTIMORE (Map, News) - Most people don’t know he exists, but Brian Adams can rattle off countless species of trees, enthusiastically describe the role of ladybugs as helpful insect predators — and do it all without taking a breath.

As Westminster’s municipal arborist, Adams is a doctor-detective who can examine a tree’s canopy and cankers to diagnose if tent caterpillars or improper pruning are killing it.

“After residents complain to City Hall and I show up, I’d say 98 percent of the time, people don’t think the city had an arborist,” he said.

Adams isn’t alone in the science of arboriculture. Thousands of licensed arborists work in Maryland, some for private companies and some for local governments, according to the Maryland Arborist Association, and most Baltimore-area counties have urban forestry experts.

“The general population probably doesn’t realize the extent of the industry and how it’s a highly technical and dangerous field,” said Vanessa Finney, the association’s executive director.

Think bucket trucks, climbing trees, power lines and limbs lost to wood chippers.

“It’s a professional industry and not just ‘go cut down a tree,’ ” she said. “It requires education, experience, a license and an exam.”

With Arbor Day in April, next month is a big deal for people in this field. Every year, association members trim and fertilize trees for free. On April 28, they will volunteer at the World War II memorial on Route 50 in Annapolis. They tackled Federal Hill last year.

At a to-be-announced Carroll school, Adams and the state Department of Natural Resources will plant trees wherever the school needs it.

“A lot of people confuse me with a tree-hugger, but I’m not,” Adams said. “I’m all about preserving them, but if there are public safety issues and preservation isn’t an option, I fire up my chainsaw.”

kvolkmann@baltimoreexaminer.com

IF YOU GO

» What: Carroll County’s Arbor Day celebration

» When: 11 a.m. April 4

» Where: Carroll government offices, 225 N. Center St., Westminster