YARMOUTH — Anyone who thought Frank Knight was your typical tree hugger would have been wrong.

The man who spent the last years of his life fighting in vain to save Herbie, the oldest known American elm tree in New England, made his living in the forestry business, clearing and selling trees across southern Maine.

Yet Knight, who died Monday at the age of 103, valued trees for their natural beauty and spent more than 50 years protecting the town’s street trees as Yarmouth’s volunteer tree warden.

“He used to joke that he probably took down more trees than he saved,” said Deb Hopkins, Knight’s friend and the tree warden who took his place 10 years ago.

“But he did save a lot of trees,” Hopkins said. “Herbie was the apple of his eye. He was passionate about that one tree because it was so beautiful.”

Knight died Monday morning in hospice care in Scarborough. A celebration of his life will be scheduled in the next few days, and Knight will be buried in a hand-crafted casket made from Herbie’s wood.

“Frank cared for Herbie for 52 years, and now Herbie will care for Frank forever,” said his son, Dick Knight, who lives in North Yarmouth.

Frank Knight was a dedicated and active citizen of the town for decades before he gained national fame in 2009 for his effort to save Herbie, a 217-year-old tree that succumbed to Dutch elm disease and had to be cut down in January 2010.

“When the Herbie Project made the news, Frank received phone calls and correspondences from every state in the country,” said his son.

Knight pampered and revered the tree that stood at East Main Street and Yankee Drive, making sure to approach it from Yankee Drive for the best view, from its rugged trunk to its sprawling canopy.

Herbie took root in 1793 — state forestry experts counted the tree’s rings — the year George Washington began his second term as president. Under Knight’s care, Herbie survived 14 bouts of the fungal disease that decimated much of the region’s elm trees.

When it became clear that the 110-foot-tall tree had to come down, Knight, then 101, was there to see it happen. Someone asked him if he was sad to see the tree go. Knight said no.

“Nothing lasts forever,” he said. “We had a great, beautiful relationship, and I thank God every night for it.”

Knight later attended an auction of keepsakes made from Herbie’s trunk that raised $15,000 for the town’s tree trust.

Born in Pownal, Knight graduated from North Yarmouth Academy in 1925 and the University of Maine in 1930, receiving a forestry degree, his son said.

He worked for paper companies in New York and Maine before going into business for himself as a wood dealer, broker and land-clearing contractor who removed hundreds of acres of trees for major highway projects and the Portland International Jetport.

He also cultivated native Maine low-bush blueberries on as many as 30 acres scattered around Cumberland County.

Knight and his late wife, Frances, were married for more than 60 years and had one son, two grandchildren and two great-grandchildren.

Knight’s son remembers celebrating the end of World War II, playing baseball and walking in the woods with his father.

“He was literally one of a kind,” Dick Knight said. “He was someone everybody could look up to. He always gave a straight answer.”

Through the years, Frank Knight served on the town’s planning board, conservation commission and library board, and in many other civic roles.

Town Manager Nat Tupper described Knight as a person with a brilliant mind and a genuine sense of caring for others.

“He was a delightful person,” Tupper said.

Many townspeople admired Knight, who made a point of welcoming neighbors soon after they moved in, even in his later years. One Portland Press Herald reader posted this comment Monday on an online story about Knight’s death:

“A car pulled into our driveway and Frank got out of the passenger side and introduced himself,” the reader wrote. “As we were talking, he pointed to a large tree on my neighbor’s property and said, ‘That tree’s dead, it just doesn’t know it yet.’ Two weeks later, it fell on my car. The man knew his stuff.”

Today, the Maine Forest Service recognizes folks who share Knight’s concern for trees with its annual Frank Knight Excellence in Community Forestry Award.

Deb Hopkins, who led the Herbie Project when Knight retired as tree warden, received the award in 2010.

“Frank was my mentor and my friend,” said Hopkins, 56, who is a hairdresser in town.

“He enjoyed being with you as much as you enjoyed being with him. You were special just because you were there with him.”

There are nine elm trees left in Yarmouth, Hopkins said, and she’s carefully watching over all of them, especially the one in front of the First Baptist Church on Main Street.

“Frank said it was almost as beautiful as Herbie,” she said.

Staff Writer Kelley Bouchard can be contacted at 791-6328 or at: kbouchard@pressherald.com