By the time he was 85, he had to stop every 10 to 15 minutes to catch his breath. His neighbors, who loved seeing him on his walks, set out about a dozen chairs along his route.

"They figured this old guy needed a place to sit and rest," Djerf said in a Trulia real estate commercial. "Very often people come out and visit with me. Takes me about an hour to go around the neighborhood because of the frequent rest stops and visiting."

He continued his walks, but this time down the aisles of a New Hope care facility up until his final days, according to his son Warren.

Now, a tribute chair with his walking sticks and his World War II veteran baseball cap sits in front of his house.

Djerf died on Sept. 1. He was 96.

Born and raised in south Minneapolis, he became an avid outdoorsman who studied forestry in college before being drafted to serve in World War II.

Later, he taught biology to middle school students in Golden Valley, and spent 30 summers working as a park naturalist at Gooseberry Falls State Park.

Kris Backlund, assistant manager of Wild River State Park, was looking for a summer internship in 1984 when she was paired up to work with Djerf as an assistant park naturalist at Gooseberry. She stayed for seven summers.

"That time with him was really the start of my career," Backlund said. "I always had an interest in nature ... and then I had someone easygoing, knowledgeable, kind and patient to work with. It really made it a good experience for me."

One of the first questions he asked Backlund was if she could remember names. That was something Djerf was good at — connecting with people.

"It validates people that you are paying attention to them and wanted to know them on a personal level," Backlund said. "For Harvey being a teacher, I think that was also important in the classroom too."

Even during his walks, he often headed for a chair, and before he could sit down a neighbor would be heading toward him for a visit.

And at Gooseberry, people started recognizing him, Backlund said. "He had his own fan club and following," she said.

Djerf was a storyteller, often telling tales about Paul Bunyan and shipwrecks during lakeshore hikes Up North.

Before state parks had "nature carts," Djerf was already doing something similar. He'd find rocks along Lake Superior, attach them to information notecards and place them out so families could learn more about the local geology.

Former biology students lauded him for inspiring careers in veterinary science and biology.

"I was grateful for the opportunity to tell him that he had been an early inspiration to me, eventually leading to a long and satisfying career as a biologist for the DNR and the U.S. Fish and Wildlife Service," former seventh-grade student David Pederson said in a Facebook tribute post, later saying in an interview: "It was an early, but lifelong impression."

Djerf was preceded in death by his wife, Pat, who died March 7; a son, Wayne, and a grandson, Adam. In addition to his son Warren, he's survived by sons Steve and Brian; daughters Laurie Geving and Mary Lee, and many grandchildren and great-grandchildren.

Services have been held.