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Planting pine or native forest for carbon capture isn’t the only choice – NZ can have the best of both

Rural News / news
Planting pine or native forest for carbon capture isn’t the only choice – NZ can have the best of both
Commercial radiata pine plantations have aesthetic and biodiversity drawbacks. Getty Images.

By Sebastian Leuzinger & Len Gillman*

New Zealand’s per-capita contribution to carbon emissions is very high by international comparison. But so too is its potential to mitigate climate change by planting forests to quickly sequester large amounts of carbon.

There is sometimes passionate debate about how best to do this. Should we continue establishing radiata pine plantations, or focus instead on planting New Zealand native trees?

Arguments for and against each option exist – but there is also a third way that could achieve the best of both worlds: planting radiata pine forests that are not harvested, but instead transitioned over time into native forests through targeted management.

We need to cut emissions drastically. But we also need to remove as much CO₂ from the atmosphere as possible, especially over the next 20 years. A transitional forest model is a powerful way to help achieve this.

Farming carbon using trees

As trees grow they absorb CO₂ from the atmosphere and lock the carbon into wood, leaves, roots and soil.

The New Zealand Emissions Trading Scheme (ETS) provides income from growing trees to store carbon. It is a key tool for meeting domestic and international climate change targets, including the 2050 target set by the Climate Change Response Act 2002.

A newly planted native forest will absorb approximately 40 tonnes of atmospheric CO₂ per hectare over ten years. By contrast, an exotic radiata pine forest will achieve five to ten times this amount over the same period.

In other words, to absorb a given quantity of carbon during the early stages of reforestation, it will take five to ten times more farmland using natives. Because of this enormous advantage of exotics over natives, there is a place for exotic carbon farming.

Some object to pine planting on purely aesthetic grounds – they just don’t like the look of radiata forests. And we agree there are some places where pine is just not appropriate for the landscape. But the urgency to mitigate climate change means we need to turn as much unprofitable pasture into forest as possible.

Radiata forests are also criticised for being monocultures that lack biodiversity. But the pasture they replace is also a monoculture that contains even less biodiversity. Planting trees on pasture also reduces gross emissions by reducing animal stock and therefore methane emissions.

We can’t plant too many trees

A year of emissions in Aotearoa New Zealand equals 78.8 million tonnes CO₂ equivalent, based on 2020 figures. To offset this for a ten-year period would require planting roughly 20 million hectares of pasture in native trees, then waiting ten years for them to grow.

The total area of Aotearoa is 26.9 million hectares, with 3 million of those being mountains. Therefore, another treeless country of a similar size would be required to fully offset its emissions using native trees alone. Using radiata pine would require 2 to 4 million hectares.

At an individual level, just one return trip from Auckland to London for one person will produce approximately 11 tonnes of CO₂ emissions. To offset this would require planting over a quarter of a hectare (almost an acre) of native trees, and waiting ten years for them to grow.

On current projections, Aotearoa will need to purchase 100 million tonnes of offshore carbon credits to meet its international commitments. According to Treasury calculations, this will cost between NZ$3.3 billion to $23 billion between now and 2030.

Obviously, the country cannot offset all its emissions by planting trees, native or exotic. Reducing emissions in the first place is the priority. But from a climate perspective, we cannot plant too many trees of any kind.

Restoring biodiversity over time

One of the criticisms levelled at exotic carbon forests is that the carbon storage is not permanent because of the shorter lifespan of pine. But pine plantations in New Zealand can keep accumulating carbon for at least a century if they’re not harvested.

Also, the carbon storage is permanent if exotic forests are transitioned into self-sustaining native forests. This process occurs naturally, but can and should be accelerated by targeted management.

Because radiata pine needs a lot of light to grow, its own seedlings will not establish beneath its canopy. Therefore, pine will naturally decline over time and gradually be replaced by native forest, a process that occurs naturally but takes many decades.

To provide crucial structural and species diversity, and to expedite the transition process, native trees requiring plenty of light need to be planted, and pine trees need to be thinned. This is nothing like commercial harvesting, so the problems associated with forestry “slash” do not arise.

Fruiting natives will attract birds and enhance seed dispersal. At the same time, the income from carbon credits through the ETS can be used for further plantings, and also to fund intensive animal pest control – a critical step towards rebuilding native forests.

Eventually, this strategy will provide both permanent carbon storage and carbon capture that continue way beyond a century. But within decades we would also see the return of large areas of highly biodiverse native forests.

*Sebastian Leuzinger, Professor of Environmental Science, Auckland University of Technology and Len Gillman, Professor of Biogeography, Auckland University of Technology This article is republished from The Conversation under a Creative Commons license. Read the original article.

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They acknowledge we need to reduce (drastically) but then assume an 'economy' (income from an ETS). Given the reduction in input energy, our fiat-bubble 'economy' continuing, is not a likely scenario. 

This is the problem with University siloing - even when there's two of them!

Of course we should be re-establishing native forest - but that's to replace the stuff we removed; that's the real base-line. Seems too many people want to start 'now' and ignore the already-drawn-down. 

But there is no way - even with their acknowledged decades-long lag time - we can sequester the extracted carbon; the energy required is too much (and it's energy we burn it for). 


"Another third way" is actually planting non radiata exotics.

Example Oak.  Guy I know brings French Oak into the UK.  Trees cut are replaced and then looked after for 150 years before being used.  Taken out one at a time, no slash problem, scared landscape etc.

Other examples exist.

I don't see the obsession for natives. Patriotism I guess.  I have heard of planted and managed Rimu.  That's good. As for exotics, some are great, some are bad.  

We need some wider thinking on this


"I don't see the obsession for natives. Patriotism I guess."

Nor do I, blinkered ideological luddites.


I've been pushing this for some time. Pest control would be the first step,then planting some low light natives that have berries. 

I've spent the evening trying to safely bring down a rotten walnut tree, I noticed epitopes growing on it. Native I think. Another long term coloniser.


It's quite simple, we will never recreate the past. To think we can plant our way to how things were 1000 yrs ago is ridiculous.

Unfortunately Homo Sapiens got in the way.

Obviously we need to plant any tree that will grow and in the next several hundred years nature will sort it self out.

Everyone have a good holiday season, always enjoy the comments.




Couple of books I've read would challenge that . 

"The end of nature" argues that man has already changed the earth so much, the natural state does not exist anywhere anymore. Another I can't remember the name of, was an English natualist visiting NZ. Her NZ host proudly shows her some NZ bush. Her reply was to list gorse, blackberry etc, pointing out a good portion of what she saw was more English than kiwi 

So it would be interesting if someone run the thesis, if humans disappeared today, would NZ revert to Native bush eventually, as previously assumed, because those conditions no longer exist.

Natives need our help, pure and experience trying to grow them along a river, is they need lots of help.

Merry Christmas Hans, and all 



I see I have misread your first paragraph, but will leave my comments as still relevant.


100% agree Hans. Those at the coal face can relate to what you are saying. Wanting NZ native bush the way it was pre human is impossible I’m afraid and hopefully we won’t waste millions trying to do this.

We need to get trees in the ground and let nature sort it as you say.

All the best to you and looking forward to a good 2024 for all.


In Wellington ATM, and went for a tour around the Miramar peninsula. It's a mix of pines and natives. They have achieved pest free status,so it will be interesting to watch the progress.

Already it seems a big improvement from the gorse covered hills around Wellington from my youth.