The once pristine forest has been reduced to a 500ha reserve managed by the Department of Conservation and had been overrun by predator species such a possums, rats, stoats and the occasional feral cat.
"Here we were in ancient forest with 1000-year-old trees and it was dead silent," Mr Fitzgerald told those at Trenz.
The company made a commitment to clearing the forest of predators and hand built dozens of kilometres of trapping lines, but soon found the numbers of pests being killed was almost unmanageable - almost.
"We could have tried to be the highest, fastest, longest, steepest or whatever, but we decided to use zip lines to immerse people in this otherwise inaccessible environment ... with the most engaging zip line experience."
He said the early days were tough with plenty of people saying it wouldn't work and only two paying customers in their first week.
But, he said the response to early media coverage by the Rotorua Daily Post and New Zealand Herald gave them confidence they were doing the right thing.
They started by sectioning off and trapping pests in a 50ha site, but soon found it was a lot of hard work and long hours manually setting and clearing hundreds of traps.
Through sponsorship deals, customer donations, a new partnership with DoC and spending $300,000 of its own money, the hard work paid off and the birds and animals started slowly returning.
Native birds and lizards have made a comeback and the company's sights are now set on a further 100ha of the forest.
"Something cool started to happen, people wanted to know how they could get involved - schools, visitors and the Rotorua community."
With DoC, they set up the Canopy Conservation Trust and the next step is to open up further parts of the forest to public access with walking tracks and facilities.
"We want the forest to become a destination in its own right ... and it all feels really good.
"Hand on heart, the environment there is better off because we exist," he said.
Tourism Industry Aotearoa chief executive Chris Roberts said the story was inspirational and showed what the benefits of true environmental tourism could produce for native plants and animals.
"James and his team should be congratulated and they were very worthy winners of our top industry award last year."
Matthew Martin was at Trenz 2017 as a guest of Tourism Industry Aotearoa.
Rotorua Canopy Tours
Opened mid-2012 in the Dansey Rd Scenic Reserve
Now employs between 25 and 40 staff depending on the season
Has spent $300,000 on pest eradication programmes
Plans in pipeline to open up more of the reserve to the public
Winner of the 2016 Tourism New Zealand supreme award