"Initially I ran at the racecourse and then started running in the Redwoods. I ran maybe eight or nine marathons with almost all of my training taking place over local forest trails.
"When I stopped running I started biking and I continue to bike today. My daily ride is 24km and again, is over local trails."
While biking through the Hemo Gorge, MacKenzie took on board blackberry restricting the view of the stream, the sections of track needing maintenance and the patches of land begging to be replanted.
Instead of rounding up troops, or seeking assurances work should be done, MacKenzie simply got stuck in.
"Over the section of track I have been working in, I've cleared quite a lot of the blackberry so there is now an unimpeded view of the stream. I've bought and planted trees and grasses and worked on maintaining the track.
As well as dealing with flora, MacKenzie has been trapping the not-so-nice fauna in the immediate area.
"My three children each bought me a trap for Christmas, the three traps have the kid's names on them, so I am able to trap as well."
So when it suits, MacKenize heads to "his" section of the Hemo Gorge and keeps working.
"What I'm doing benefits me as much as it benefits all of the people who use the track. I enjoy the physical aspect of the work as much as I enjoy the mental preparation of planning and planting."
Admitting one of the drivers behind his volunteer work was getting away from people, MacKenzie said he often saw animal owners who were clients of his former business.
"I'm forever stopping to chat but that's okay."
He said while there were many volunteers who chose to work in a team environment, he was quite happy doing what he did.
"The Hemo Gorge is only 2km from my home so I can head down when I feel like it and put in as much time as I want to without having to rely on, or inconvenience, anyone.
"It's a really lovely environment to work in and, as I've said before, I get as much out of it as I'm putting in."
MacKenzie said the volunteer work was a way of giving back to the town and, in particular, the forest trails that had given him so much.
"It also allows me to help counter my carbon footprint.
"I know there are a heap of organisations, services and groups people can volunteer at – things like the Rotorua Menz Shed – but what I do makes sense for me."
Dave Donaldson from the Rotorua Trails Trust said if the trail work carried out by volunteers had to be replaced with the services of a professional contractor, it would be a costly exercise.
"As well as the work of individuals, the Trails Trust has a monthly working bee," Donaldson said. "There are a couple of legends who regularly turn up for these."
He said while the work carried out by volunteers was often described as therapeutic by those doing it, it was almost always acknowledged by the Rotorua community.
"I believe the volunteer work contributes to the sponsorship the Trails Trust is able to obtain. People in Rotorua appreciate the trails, appreciate the work done in maintaining them, and happy to help out financially."