During his time with Tasman, which became part of Fletcher Challenge in the early 1980s, his work covered all aspects of the forestry sector.
"I feel sorry for people now who come out of university and go straight into spreadsheets," he said. "We saw the whole life cycle of forestry. It was tremendous training, which is not available to a lot of people these days, unfortunately."
After he fulfilled his five-year commitment, Tasman made good on an agreement to support him doing a postgraduate engineering qualification at Oregon State University.
He returned after two years, becoming first KLC's roading engineer, then chief forester for Tasman's forestry division, then their forest manager. After the merger, he relocated to Rotorua in 1984 and worked for Fletcher in a number of roles, including exports and marketing, as it became the first company to ship logs to both China and India.
His assignments also included travelling to the US to muster institutional investor funding for Fletcher when it began a programme to acquire forests as the New Zealand government forests became privatised.
"It was the early days of international institutional investment in forestry and we had to really sell the forestry story," he said. "Very few funds knew the sector, or had heard of Fletcher Challenge or Radiata Pine."
Bryce Heard, chair of the Forestry and Wood Processing Action Group for the Central North Island, said Mr Neilson had been his right-hand man for many years at Tasman, and described him as a colourful and entertaining character.
"He's a one of a kind and he hasn't slowed down with age," said Mr Heard. "He's a very clever guy. He works outside the square and says what he thinks. But whatever he tells you, no matter how beyond the bounds of normality it may sound, you want to listen because there's always a grain of truth there and often a big grain."
It was Mr Neilson's engagement with the international market that sparked his decision to set up his own business, and after two decades with Fletchers, he left in 1992 to form DANA.
The company undertakes benchmarking, strategic planning, investment and marketing assignments for corporate clients in New Zealand, Australia, North and Latin America, Asia and Europe, and has also been involved in forest acquisitions. In addition to providing advisory services, DANA has been responsible for producing 50-plus in-depth multi-client reviews on the forestry and wood processing sectors, which are sold to clients in the company's extensive global data base.
"We've got a feeling for what New Zealand forestry needs to be, what it could be and why it's not," said Mr Neilson.
A frequent speaker at international forest sector conferences, he has increased DANA's focus on the event sector over the past couple of years. The company now organises about half a dozen conferences a year. Earlier in 2016, he and his local partners organised US conferences in Portland and New York. This year's schedule will also include events in Panama City, Melbourne and Bangkok, as well as the New Zealand Forest Wood Processing Sector Seminar in Rotorua in August.
DANA also offers guided field trips to key wood sector markets. The consultancy will be following up a successful visit to China last year, which drew attendees from around the world, with the China Plywood and Medium Density Fibre factory tour in China in October.
Boston-based Bob Flynn, director of international timber for RISI, who partners with Mr Neilson on events in the US, and has co-authored several reviews with him, said he was widely regarded as a global expert on timberland investment.
"His background in the forest industry and his insatiable appetite for travel have given him a unique perspective on how the worldwide forestry sector is evolving," said Mr Flynn. "Dennis is known for keeping a gruelling schedule that would exhaust a forester half his age, and has an amazing knowledge of both the costs of forest development and the international markets for forest products.
"He has spoken at so many timberland investment conferences, and organised so many, that it is impossible to count. Everyone - and I mean everyone - in the industry knows Dennis. If he is on a conference programme, he is the one speaker no one wants to miss - he's always knowledgeable, consistently interesting and never boring."
Still plenty to do every day
Dennis Neilson enjoys getting out fishing with friends on their boats. And he remains a keen traveller, despite having spent much of his career on the road - including more than 50 visits to China.
He's a longtime member of the Rotorua Rotary Club. He and his wife Linda, who is planning and information manager at Waiariki Institute of Technology, are looking forward to a cruise of the Greek Islands next month.
They have three sons - a control systems/robotics engineer in Auckland, a physics professor in Philadelphia, and a banker in New York. They have daughters-in law from Japan and China, and two grandchildren. And at 66, he is working harder than ever.
"I'm enjoying it. I wake up every day and have half a dozen interesting things to do. I feel sorry for people who retire or tell me they are bored with their jobs."
Dennis Neilson:
* Role: Founder/director, DANA
* Born: Wellington, New Zealand
* Age: 66
* First job: Graduate forestry trainee
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