But Forest Owners Association president Peter Weir has challenged that figure on grounds the sheer scale of plantings cannot be satisfied by land that might not exist, is already planted or is unsuitable for commercial forest plantations.
The Government is committed to planting an extra 50,000ha a year of new forestry for the next 10 years.
But the commission’s plans mean that rate would have to continue for another 23 years beyond 2027 to achieve the mid-point of 2m hectares in new forestry area.
“But if we start with the South Island it’s not looking likely that the east coast region will be seeing any of that,” Weir said.
“Catchments through Marlborough, Canterbury and Otago have been labelled water short and unsuitable for forestry and so resource management regulations will not enable regional councils to allow plantings in those areas.”
Weir acknowledges the potential for parts of Southland to be planted but said higher land prices in the water-rich region will probably prevent foresters investing there.
“And the West Coast already has significant forest areas in place.”
Looking up the east coast, legacy irrigation projects mean the catchments of most major rivers are protected and disallow forestry planting.
One exception is the Clarence River catchment in North Canterbury, which has no irrigation schemes on it.
That could open up the potential for a large swathe of land on 1800 square kilometres of Molesworth Station to be planted but would require Conservation Department approval, unlikely to be given.
The requirements forestry to be classified as new include land has been in grass since 1990 or land that has been repeatedly cleared of bush before its height exceeds 5m.
“So, now we have issues around Maori land and land that has reverted so that will raise social equity issues around how well iwi will be able to participate in any afforestation schemes.”
That could have a significant impact on country around East Coast under iwi ownership.
It is the same area affected by falling under the red zone classification for erosion. There are four colour codes for erosion, with red the worst and unable under resource consent conditions to have clear-fell pines planted on it, the most profitable form of forestry.
The red zone for erosion extends to parts of King Country, Wanganui, Hawke’s Bay, East Cape region and Bay of Plenty.
“So this raises the question, what will the planting model be for erodible country in the North Island?”
The erosion descriptor applied mainly to the steepest land use capability classes 7 and 8.
Weir said drilling down into what areas could be suitable does not reveal any vast swathes of land.
“I think Shane Jones’ extra 50,000ha a year for the next 10 years is achievable but beyond that? That is where I would argue the commission’s big ambitions will struggle to play out.”
Some winners from the restricted planting on extra steep country could be manuka growers seeking more land.
“By legally removing the ability to plant clear felling forests from that steep country they will welcome the opportunity not to have to compete with other forestry for that country.”
The call on sheep and beef farmers to surrender 2m hectares also has Beef + Lamb NZ smarting.
B+LNZ insight officer Jeremy Baker said the organisation’s recent Norton Report highlights how much land is already held in forestry by the sector.
Across the sector’s 8m hectares about 1.4m is in tussock/open bush and a further 1.4m is in regenerating native bush.
With such areas already committed, the 2m hectares sought by the commission will have to come out of about 6.2m hectares of pastoral land.
“Farmers have already put the land aside for very good reasons and are unlikely to rip that up for plantation forestry, which also only has shorter-term carbon benefits compared to long plantation native plantings.”
It was ironic sheep and beef farmers are expected to come up with such a significant area when they have reduced carbon emissions by 30% since 1990.
“I do think however the commission has had a tough job. I do not think they are confident they will see a reduction in CO².
“Maybe they were thinking they could soften the move to lower carbon emissions by having a fat carbon sink there but this will not give them the quick sugar fix they seek,” Baker said.
Where will trees go?
The Productivity Commission modelled three scenarios for afforestation, based on the scale and nature of technology development and the rate of decarbonisation.
Commission staff said changes in land use are likely to vary considerably across regions, with the greatest change in absolute terms occurring in Canterbury where forest area could increase by 400,000ha to 600,000ha, accounting for about 20% of total afforestation. That is followed by Otago with 350,000ha to 500,000ha.
Manawatu-Wanganui could increase forested area by 300,000ha to 400,000ha, with all shifts coming from sheep-beef conversions.
However, as a share of total land area, the greatest afforestation would occur in Gisborne, Wellington and Nelson.
The results suggest new planting in Gisborne could cover about 22% of the region and 17% of Nelson/Wellington.
The greatest percentage reduction in sheep and beef land would occur in Marlborough.
