A carbon farming business has bought swaths of New Zealand and planted it in pine trees, promising it would one day regenerate into native forest but researchers who have studied the concept doubt it will work. Source: Stuff NZ
New Zealand Carbon Farming (NZCF) has quickly grown to be one of the country’s biggest landowners, with more than 89,000 hectares either owned or leased. NZCF says it is the biggest provider of carbon credits in Australasia and the biggest participant in New Zealand’s Emissions Trading Scheme.
The business model is to find farmland with remnants of native forest nearby to act as a seed stock, then plant pine, which grows quickly and supplies a stream of income from carbon credits. The company says it selects sites with enough rain and decent soil, and that it will thin the pine and control pests, such as deer and possums, to enable indigenous forest to grow underneath (and eventually take over).
But two forestry scientists who helped pioneer the pine-to-native forest concept in New Zealand question whether native regeneration will happen on the scale the business is attempting.
Adam Forbes is a former research adviser to NZCF. Before joining the company, he did his PhD research on using mature Pinus Radiata to mimic the environment of a sheltering native forest. His research has been cited by NZCF: a recent article by company employees in the NZ Journal of Forestry cited five studies of which Forbes was the lead author, as well as studies by Forbes’ PhD supervisor, the University of Canterbury’s Professor David Norton, among other research.
Forbes resigned from the company in 2019. He told Stuff he questioned whether the business had conducted enough trials to know that its plan would work in the various climates in which it owns forests.
“We have some pretty chunky issues around native forest regeneration, like feral animals [and] weed issues, which are really tough to tackle at scale,” Mr Forbes said. “The active management required for that sort of forestry, when you start doing it at the scale of 10,000 hectares or more, requires such a lot of work that it becomes unmanageable.
“If they don’t get it right, we are going to end up with large areas of pine that will be hell-of-a-difficult to work with, and probably harbouring a lot of pests, if it is not managed,” he said. “The pines will only live for up to 200 years, we think, so what are future generations going to be left with … if they are not successful in getting a native canopy away in some of these areas?”
NZCF managing director Matt Walsh said the business respected the need for more research but said there were dozens of studies already on forest regeneration, some going back 50 years. Further studies were being done at the same time as the planting was being rolled out, he said.
“Before we launched the business, we took scientific advice on the strategies that would enable us to reconcile the inherently slow-growing nature of indigenous trees with the urgent need for carbon removals,” Mr Walsh said.
“While many scientists will look for the perfect set of “proof” before endorsing any solution to any problem, the reality is that the planet cannot wait for the perfect data set. We need to take action now and at scale,” he said.
Norton, the Canterbury professor who was Forbes’ PhD supervisor, is not convinced. He met NZCF executives recently and said they showed him evidence that some of their plantations were in suitable locations, with suitable natural seed stocks available.
However, he remained sceptical that the business had adequate long-term management plans in place, or enough guaranteed long-term funding, to turn native forests into reality.
“They could show me they had killed a lot of goats but that was for establishing the pine trees. I could not see that they are yet thinking about how [native forests] will establish over 50-100 years,” said Mr Norton.
“We know as pine trees get older, the carbon sequestration starts to taper off – particularly after about 50 years. The concern is that at some point a disease or whatever knocks those trees out badly and there is a big gap in carbon income, and where is the money going to come from to fund the management?
“The areas they showed me would go faster into native forest if they had just had the goats taken off them and been fenced, rather than planting pine, but that doesn’t give you the carbon credits,” said Mr Norton.
Mr Walsh said that despite looking, he and his business partner had not been able to find an investment model for indigenous tree planting that could be privately funded without major subsidies while also providing massive carbon sequestration during the next few decades. “This is one of the key reasons why we have elected to go down the regeneration path,” he said.
NZCF was established in 2010 and estimates forests under its management gave sucked in more than 20 million tonnes of carbon dioxide – the equivalent of almost a quarter of
the whole country’s annual emissions.
However, since NZCF launched, the tide of opinion has increasingly turned against using pine for carbon storage, with the Climate Change Commission’s recent advice to the Government leaning towards planting more native trees and tapering off on planting new pine, particularly after 2030.
Discussing the pine-to-native trees pathway, the commission noted that regenerating native forest under pine could take centuries and, along the way, unharvested forests could cause problems with wilding pines or trees falling over if they were not carefully managed.
Indigenous forests, while slower to accumulate carbon, bring more biodiversity benefits and may prove more resilient to climate change than monoculture, researchers have found.
