In an issue dedicated to the “legends” of the industry, there’s no avoiding the name Mark Chisholm. His official tree-climbing career began more than 40 years ago, at age 12, helping with his dad’s business on weekends. He was making money rigging out trees before many in this industry today were born. But don’t let that fool you. “I could outclimb my 26-year-old world-
championship self today,” he says.

Chisholm is, in some ways, ageless. Talking to him, you get a sense that he only gets tougher, stronger and more athletic as he ages. And that he might be doing this work, with effortless power and enviable style, well into his 60s – or longer.

I caught up with him over the phone while he was on the road to New York City to give a presentation to about 150 New York City parks arborists. We spoke about his innovations, his passion for sharing knowledge, the importance of competing, trends in the industry and what happens as arborists age.

Mark Chisholm serves as an ambassador for Stihl Inc., among other companies.

Influence of competition
“I just feel lucky that I get to go to work in this industry every day. This is a great industry to be a part of,” he says. I asked what he thought of being tapped as a “legend” of the industry. “The way I feel is, I didn’t do this, I’m just a part of this. I was shown the way. I had mentors. It’s a huge honor, obviously.”

It’s not an overstatement to say that the field of arboriculture would look a lot different were it not for Chisholm’s influence over the past four decades. Being relatively new to the industry myself, I asked for an example of his innovative spirit, something that created a shift in how regular arborists went about their daily tasks. To this, we turned to his prodigious competition days. Mark is a 20-time New Jersey Tree Climbing Champion and three-time World Tree Climbing Champion.

At a Glance

Mark Chisholm

Name: Mark Chisholm
Job title: Co-owner and director of operations
Company/organization: Aspen Tree Expert Co.
City and state: Jackson, New Jersey
Additional job titles: National spokesperson, Stihl Inc.; ambassador, Kask; ambassador, Teufelberger
Years in the industry: 40
Credentials: New Jersey Licensed Tree Expert, TCIA CTSP, ISA Certified Arborist, ISA Certified Tree Worker
Area(s) of impact: Writer, educator, trainer, web-content creator

Back in the early 2000s, he explains, “I was trying to problem solve for an upcoming competition, looking for a competitive edge.” He spent “day in and day out” practicing his climbing in order to get a leg up on other climbers, which, he casually mentions, contributed to his overall fitness, competence and productivity during the work day.

That “competitive edge” came in the form of his decision to incorporate mountaineering gear into his tool bag. At the time, tree climbers were climbing on half-inch or larger-gauge ropes. Mark was convinced that lighter, smaller-
gauge ropes were the way of the future, and might be his ticket to victory. Chisholm went to his go-to rope manufacturer at the time to work out the kinks, and soon, “The Fly Line” from New England Ropes was in his hands. (With New England Ropes, Chisholm would go on to design the HRC (heat-
resistant cord) Prusik cord, still ubiquitous today.) He used it for the first time in 2002 in a competition, to shouts of “I don’t think that’s gonna fly,” a play on the rope’s name.

“Everyone laughed at us at the time. No one thought a smaller-gauge rope would ever take off. But as soon as the competition climbers got hold of it, they all loved it.” Half-inch or larger climbing lines are still around, but most climbers these days use something smaller and lighter, in large part thanks to Chisholm.

Mark Chisholm ascends a redwood. Unless otherwise noted, all photos courtesy of Mark Chisholm.

Sharing knowledge is the key to success
Asked about his bent for sharing knowledge and his approach to doing so, Chisholm says, “For me, it’s a part of who I am. I was shown that way by my father, brother and other mentors growing up.”

He mentioned a friend from Belgium who, in the mid ’90s, “changed the way I climbed” by being the first ever to show him how to use a Prusik to climb. This new knowledge transformed his climbing, and he felt inspired by the way knowledge could trigger such transformations. “The tragedy of knowledge is keeping it to yourself.”

Chisholm spoke with evident pleasure about his years in the competition world, and how he “couldn’t wait to share new techniques and ideas,” even with his competitors. He announced with mock concern that his “toxic trait” is “trying to make all my conferences happen because of this passion for sharing.” I got a picture of him weaving through tightly laced traffic in cities from coast to coast and even abroad, working to fit in climbing, exercise and family, and somehow still making time to speak at conferences and trade shows. It must take some passion, indeed.

Benefits of climbing competitions
My local chapter’s tree-climbing competition was on my mind when I asked if he believed it’s important for climbers to compete. “The best climbers, you’ll find, either go to competitions or are very close to someone who does.” I pressed him for more. “The best, most cutting-
edge arborists are somehow around or associated with the competitions. Not everyone wants to compete, but you can get a lot of the same benefits by networking with the folks there. Volunteer for them, watch them, work with someone who climbs in them. So many people don’t give the competitions enough credit for what they bring to the industry (innovation, pushing the borders of the industry). It’s a mistake for people not to be active and involved in these events – same goes for the expos.”

Sharing with other arborists
So what advice does he have for the aging arborist? Chisholm has done many talks and presentations on this very topic, and was recently featured on a Tree Awareness podcast, “The Aging Arborist” (The Aging Arborist Episode 2: Mark Chisholm (youtube.com)), which I recommend. I was curious about Dr. John Ball’s recent article, entitled “The Role of Age in Fatal Incidents” (TCI Magazine, August 2024), and any reflections on it Chisholm had to share.

“If you’re prone to accidents, it’s usually on account of mental focus. Mental error is really the only reason you’re having these accidents.” What can help that? “Be engaged, stay excited, develop protocols around how you operate – look at others your age and keep track of how and why other aging climbers are doing what they are doing.”

“The tragedy of knowledge is keeping it to yourself,” says Mark Chisholm, shown here on the job.

It can’t be entirely mental, I parried. Chisholm felt strongly that it was primarily a mental game, but talked passionately about the physical aspect of tree work. “You have to do the hard stuff as often as you can. The human body gets weaker the less you stress it. It’s a mindset – embrace the strain and struggle.”

I asked what he does besides tree work to stay fit and active: “Hockey once a week, physical fitness almost every day. I play golf on weekends with friends, and when I do, I walk and carry my bag. Don’t shy away from the physical aspects of anything. Functionality comes from physically working at it,” says Chisholm. “Doing hard work makes you able to do hard work longer.”

Three pillars for longevity
Chisholm left us with his three pillars to focus on for longevity in the industry:

1. Safety – PPE, gear inspections, etc.
2. Treat yourself like an athlete – workouts, nutrition, rest and recovery, etc.
3. Be a student for life – attend conferences, workshops, competitions, etc.

Jim Kasper is an ISA Certified Arborist and Climber Specialist. He has a master’s degree in public health (MPH) and is a climber with Gill Tree Care in Decatur, Georgia.