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Why we need to plant more native trees than pines

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We do need more trees, but native species may be a better long-term choice than pine trees.

One reassuring fact cuts through all the warring assertions and proposed sacrifices and priorities in our forestry debate: every new tree is doing us good.

More trees and bush could store about a quarter of the atmospheric carbon necessary to limit global warming to the 1.5°C above pre-industrial levels that the Intergovernmental Panel on Climate Change (IPCC) deems essential.

The IPCC is talking about the heavy-lifting vegetation of forests, woodland and woody savannah, which globally absorb about two billion tonnes of carbon a year.

Other forms of vegetation contribute, too: horticulture, shelter belts, riverside planting, even gardens. But it remains one of the few uncontroversial aspects of our policy wars that, wherever and however, we do need more trees, and in such volume as to make reafforestation an incontestable imperative.

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It’s not just because trees sequester carbon, but because, given the right trees growing in the right place, they prevent soil erosion, help ensure clean rivers and provide habitat for native fauna and other flora. Overseas researchers are even pondering new evidence that trees emit chemicals beneficial to human health and/or happiness. Even when the forests are cut down, they don’t necessarily return all that carbon to the atmosphere. Long-life wood products such as housing and furniture keep it locked up, and there’s a global trends towards quality, non-disposable consumables that should see that trend continue.

Given our decision to depend so heavily on carbon sinks, we need to do much more than just replace the commercial forests we lose – and we’re losing them at a brisk rate these days, so for now we’re just playing catch-up. The last planting boom (mostly Pinus radiata) in the 90s has lately been yielding its crop, leaving our plantation size reduced from its 1.8 billion hectares peak in 2003 to 1.7 billion.

Native forest covers 7.8 million hectares, 1.3 million of that lower-carbon-soaking regenerating forest or nursery scrub such as mānuka, kānuka and gorse.

All that will need to more than double. The Productivity Commission estimates we’ll need to commit up to 2.8 billion more hectares to forest to meet our 2050 goal. The One Billion Trees target gets us to 230,000-430,000 more hectares in 10 years. It’s easy to see why Forestry Minister Shane Jones has been publicly impatient with the bureaucratic – though generally prudential – roadblocks put in his way, and why he rues criticism that he’s going too fast.

The 50,000ha of annual planting implicit in his Billion Trees push would have to continue at its existing target rate for a further 20 years to meet our climate-change target.

So far, aside from an embarrassing scrub-cutting failure delaying planting on a Northland block, the trajectory of Te Uru Rākau (Forestry NZ) has been brisk. It says it will achieve half the 2028 target via replanting of existing commercial forests, 1.7 million of mainly Pinus radiata. The rest is expected to come from a mix of planting and native-regeneration grants and joint ventures with the likes of councils, non-governmental organisations, training institutions and Māori entities.

So far, for $30.4 million, Te Uru Rākau has entered into 15 partnerships – including a native-seed-planting trial and forestry-skills training pilot for prison inmates – and approved 36 planting grants, reserving a further $36 million for erosion mitigation.

Its business arm, Crown Forestry, is engaged in 21 joint ventures turning private blocks of 200-plus hectares of land into commercial forest.

In March, the 127ha Stoneleigh Forest in Waikato became the first forestry block sold under new Overseas Investment Office regulations for land or cutting-rights investment, to Oji Fibre Solutions, part-owned by Oji Holdings in Japan.

The Budget added $58 million for Te Uru Rākau to support local foresters and landowners in the regions.

All told, 61 million trees have been planted towards the “Billion”.

But so much pine? As the Department of Conservation’s war on weeds continues its Sisyphean mission to curtail wilding pines, our massive upscaling of firs for carbon sink has its downside. Jones says governments will just have to keep upping the weed-control budget.

There’s no getting around the fact that Pinus radiata is a fast grower and therefore soaks up carbon more quickly. It’s not, however, a forever tree, and investors’ carbon-credit dial will be reset to zero every few decades when the trees need harvesting and replacing.

This, it is hoped, is where more sophisticated forestry management and – to use a trigger word – perhaps even gene technology, gene editing or modification might click in in time. Opposition climate-change spokesman Todd Muller says National is open to the potential of gene-edited trees, which could optimise our carbon sequestration in the future. But with continued public intolerance of gene-related solutions, that future is on few other agendas.

However, it’s evident the catchy simplicity of “right tree, right place” might be sparking as much eye-rolling as endorsement. There’s nothing simple about it – ETS earnings incentives aside. From the pending new Government regulation of factors affecting water quality and its push to codify and protect productive land, to the new ban on marginal lands forestry, there are growing caveats on tree choice.

The Environmental Defence Society (EDS) is calling for a comprehensive plan to make it clear to all comers what should and shouldn’t be planted where, particularly now when the One Billion Trees Programme is still just a seedling. “You wouldn’t want to go too much further down the track without understanding the implications of what you are doing and how you decide what the right tree in the right place actually looks like,” says EDS director Gary Taylor.

He says the programme shows a lack of “joined-up thinking” across a lot of dynamic elements affecting our landscape. “You don’t want to suddenly plant a whole lot of trees and effectively sterilise that land for any other use over the next 30 years, if it is a commercial pine plantation, without some clarity about where we are heading with land use.”

Native forests are more expensive to plant, do not provide as many jobs and grow more slowly, so sequester less carbon than exotics in the same time frame. But they’re better at stopping erosion, keeping sediment out of waterways and providing habitat, and over their longer life, they carry their weight in carbon storage.

“We need both pines and natives,” Taylor says, “but much more of the latter.”

The society wants the overlay of a new incentive programme that acknowledges the carbon, biodiversity, soil, landscape and freshwater benefits and employment opportunities (growing seedlings, planting and tending trees, controlling predators) of native plantings.

“So, if you have a carbon-sequestration incentive, you layer on top of that your biodiversity-enhancement incentive and your nitrogen-reduction incentive, if there is one, and your sediment-load incentive. If you price all these things properly, you could conceivably end up developing a more potent incentive for longer-term native afforestation than short-term commercial pine afforestation. If you have some land you want to forest and it is the kind of land most suitable for permanent native forest because it is steep and erosion-prone, then you have to factor that into the incentive programme.”

Right tree or wrong tree, who’s going to do the planting remains a fair question. Forestry directly employs more than 25,000 people to gross $5 billion in annual earnings – about 3% of the economy. Business-confidence surveys understandably report the sector is bullish, but fewer than half of foresters expect the Billion Trees push to affect them short-term. There’s an understandable preoccupation with the business end of things, chiefly how the US-China trade wars might affect log exports. Currently, the logs are fetching consistently high prices, chiefly as a result of Chinese demand.

But labour-force issues are starting to bite. Industry estimates just on the harvesting side point to a 1000-worker shortage. Forestry skills are beginning to be taught in some schools, given the obviously expanded career path. Te Uru Rākau  has worked with the Ministry of Social Development to place 125 new silviculture workers, and has referred another 300 for consideration. It has also fostered 51 people into training.

So far, aside from a modest boost to industry training, the Government’s interim solution is to import seasonal labour under the temporary immigration-visa system. Immigration Minister Iain Lees-Galloway has said he expects the new Regional Skill Shortage List will allow overseas workers to fill workforce gaps in forestry planting, as the past system has done for the vineyard and horticulture sectors.

But as the planting is temporary, seasonal work, and requires a degree of physical fitness, there are doubts – including privately from within the Cabinet – that Jones’ ambition for it to be the thing that gets his “ne’er-do-well nephs” off the couch will be realised.

This article was first published in the July 6, 2019 issue of the New Zealand Listener.