Former Labour minister Stuart Nash said in his time with the portfolio he had a dream for how the Emissions Trading Scheme (ETS) would benefit the country.
"With the ETS, for the first time ever there’s been an economic incentive to plant up land that should have never been cleared in the first place," he said.
But forestry conversions, since the incentive was introduced, where dense pines were planted with no plan to harvest the mature trees, were not good, he said.
"You will end up with an ecological disaster in between 80 and 100 years," he said.
He understood that some legislation was developing to help restrict the planting of pines, but said you still can not tell farmers what to do with their land and their money.
"I don't know if that's the right route," he said.
"Farmers get pretty p..... off ... because what it does mean is, their farm which may be worth, $10 million to a forester is now only worth $7m."
The Climate Change Response (Emissions Trading Scheme-Forestry Conversions) Amendment Bill passed its first reading in June.
It proposed restrictions to the quality and proportion of arable land that could be planted in trees.
Mr Nash had a masters degree in forestry science and previously worked for construction, paper and forestry giants Carter Holt Harvey and Fletcher Challenge.
His ideal for carbon farming was that pines would be planted low density, for no longer than 50 years, while at the same time seeding natives.
In this ideal situation, carbon farmers would not be allowed to collect credits or money on pines past that 50-year cut-off.
He said research by the sustainability charitable trust Pure Advantage showed that Mānuka could be a just as fast growing and carbon-absorbing alternative to pines.
While he was the minister, he said the research needed more time to cook and the good thing about pines were that they were the most hardy.
"It's the over-boiled Brussels sprouts of the trees," he said.
"Not many people like it, not many [bugs and diseases] like it [either]."
Coming from Napier, he had seen the devastation Cylone Gabrielle and Cyclone Hale had on the east coast of the North Island in 2023.
This was where trees on farms would have come in handy, he said as roots made the ground more hardy, and would have prevented slips and other soft ground corrosion after the floods.
A lot of New Zealand land should never had been cleared for farming and he said it was expensive to plant hilly, non-productive land, without incentive.
He said despite seeing the benefit of forests and the ETS for the land, he by no means wanted to see highly productive farms and soil turned into carbon farms.
"I'm really loathe to tell farmers what they should and shouldn't do," he said.
"But I'm very happy to tell carbon farmers what they should do."
