As part of the global Covering Climate Now initiative, the Herald is dedicating a week of coverage to the issues surrounding the climate crisis. In the second of a series of in-depth interviews with leading experts on key policy areas, Herald science reporter Jamie Morton speaks with Dr David Hall, of the AUT-based Policy Observatory, about how we can ensure our forestry settings are climate-friendly.
New Zealand has long relied on forestry as one of the main ways to meet our climate change obligations. Can you explain how this has worked, and why forests are important in mitigating climate change?
Our international obligations are defined as net emissions.
Roughly speaking, that's all the emissions we're producing, minus the emissions that we're removing from the atmosphere.
At this point in time, the most cost-effective and available technology for removing carbon dioxide from the atmosphere is trees.
Since we joined the Kyoto Protocol in 1990, forests have been offsetting at least one-third of our gross emissions, sometimes more.
If we're planting lots of new forests, like we did in the 1990s, then their contribution grows.
But if we're converting forests into pasture, like we did last decade, then our gross emissions start sticking out like a sore thumb.
What's your carbon footprint? Try this five-minute FutureFit survey, supported by Auckland Council, to find out.
Some people are excessively cynical about the role of forests.
One meme that took hold a few years back is that carbon removals from plantation forests is like making purchases on a credit card, which eventually need to be paid back, because, at least in accounting terms, when you harvest a forest the carbon effectively returns to the atmosphere.
But this is a poor metaphor.
Instead, think of carbon dioxide in the atmosphere as water in a bath.
If you fill a teacup from the bath then pour the water back in, then, to be sure, we're back to where we started, just like the credit card metaphor says.
But if you have, say, 100 teacups, or 100 forests, all scooping up and pouring out the bath water at different times, then actually the bath water will settle at a lower level, because at any single moment there will be lots of teacups withholding a substantial volume of water from the bath.
That gets us closer to what plantation forestry does.
It creates a flow of land-based carbon that, on average, over consecutive rotation cycles, reduces the volume of atmospheric carbon, even though it's being harvested intermittently.
Also, if some teacups aren't being emptied back into the bath, which is more like what permanent or continuous cover forestry does, then the water level will go lower still.
In short, it isn't just about the permanence of the forest, it's also about the permanence of forest land uses.
Where have we been getting forestry wrong, in a climate change context, and why?
One big issue is using forestry as a substitute for reducing gross emissions.
The academic term for this is "mitigation deterrence".
If the cost of sequestering carbon is lower than the cost of preventing emissions, then companies are deterred from the more urgent task of actually preventing further emissions from entering the atmosphere.
From the perspective of global climate strategy, this is a bad outcome, not least because the higher the levels of atmospheric carbon, the greater the risks to forests from global warming, such as heat stress and extreme weather.
We really need to stabilise temperatures if forests are going to provide the long-term carbon storage that we want them to.
And that relates to the second big issue: that New Zealand's climate policy has put too much emphasis on climate mitigation and not enough on climate adaptation.
Ultimately, we need to strike a balance between these, but by pursuing the mitigation potential of forests so single-mindedly through the New Zealand Emissions Trading Scheme (ETS), we're at risk of perverse consequences from an adaptation perspective.
First, we tend to overlook the role that more strategic tree planting could play in enhancing the resilience of landscapes and catchments.
Second, we're at risk of planting forests that are vulnerable to climate change.
The Emissions Trading Scheme is calibrated to discover the least-cost emissions reductions; it's indifferent to other issues like adaptation and biodiversity.
By monetising carbon sequestration, it creates a financial incentive for forests that are cheap to plant and quick to grow.
Pinus radiata is hard to beat on this front – which is why it'll continue to play an important role in forestry.
But from a climate adaptation perspective, it isn't a good idea to have a national forest estate that's all in one species.
On the contrary, the first rule of resilience is diversity, diversity, diversity.
As climate-related risks increase, you don't want all your eggs in one basket.
In coming years, extreme weather events will become more frequent and intense, including windstorms, droughts, and fire risk.
Pest and disease vectors will change, and stressed forests will be more susceptible.
Our best defence is to diversify our forests, to spread our risks, and also to introduce greater biodiversity into the forests themselves, in terms of diverse tree species, age class, and silvicultural systems.
Yet if the ETS incentivises a lot of densely planted, even-aged pine monocultures, then we're setting ourselves up for catastrophic forest loss because these forests are vulnerable to the same shocks.
At the end of the day, the purpose of the exercise is mitigating climate risks, but a least-cost approach won't necessarily get you there.
To help meet our commitments, the Climate Change Commission recently recommended New Zealand could establish 380,000ha of new exotic forestry by 2035. It also found that new native forests - could be planted on less productive land, such as an estimated 1.15 to 1.4 million hectares of erosion-prone areas. Did you agree with its general recommendations around forestry?
It's no secret that I've been advocating for something along these lines for several years now, ever since I wrote the Our Forest Future report in 2016.
So, yes, I'm onboard with the Commission's general direction of travel.
The push for natives is an important part of diversification, as well as aligning to tikanga taiao.
One thing I'd add is that the commission's advice tends to fall into a trap that's bedevilled this conversation for years, by treating natives and exotics as an either/or choice, rather than a continuum of options with various risks and opportunities.
On the one hand, even using other exotic tree species to diversify away from Pinus radiata will increase the resilience of the national forest estate.
Exotic species can also play a role as a nurse for native species, like gorse did at Hinewai Reserve on Banks Peninsula, or eucalypts at Milnthorpe Forest in Golden Bay.
On the other hand, if "native forest" means a monoculture of mānuka, which it often practically does, then it isn't at all clear that this is an improvement on pine monocultures from a climate adaptation perspective.
Mānuka is actually pretty flammable and there's even an incentive to clear the mānuka after 25 years or so when honey production declines.
So, again, it comes back to this issue of diversification, which makes the forestry issue endlessly fascinating, but also endlessly difficult for the blunt tools of policy.
If native forests grow slower than exotic species like Pinus radiata, then how can we justify planting native forests in a climate emergency?
We need forests that people want to live with and look after.
For Māori, native trees are taonga; they're connected to these species by whakapapa and have a duty to protect them.
And many non-Māori farmers and land managers also have a strong preference for native trees, because they have a sense of stewardship, a land ethic.
They want to leave the land better off by restoring native habitats and wildlife.
There are always a lot of non-financial motives at play in land use decisions.
Some foresters get frustrated by this and the resistance to pine trees, but, speaking as a political scientist rather than a forester, this is a social reality that needs to be taken into consideration.
If climate emergency means running rough shod over people's values and aspirations, then we'll just end up with resistance and pushback.
I think we're much better working with people's actual motivations than trying to force unwanted outcomes.
No matter how slow a native tree grows, it will still sequester more carbon than a pine tree that doesn't get planted.
So let's enhance people's capabilities to plant the trees that they really want and take whatever carbon we can get.
And in any case, it's a good thing to have slow-growing, long-lasting forests as part of the mix.
The world is quite likely to overshoot the carbon budgets for 1.5C and 2C, so we even once we've ceased emissions, we'll need negative emissions to scrub carbon dioxide from the atmosphere and bring down global temperatures to a safer level.
If we plant native forests today, then they'll be delivering those negative emissions when we need them most, in the second half of the century.
The commission noted there were currently limited incentives for landowners to change less-productive farmland to permanent native forests – either through planting or by letting it revert. What could New Zealand do to encourage more planting of native forest?
When it comes to native forestry, the biggest single lever would be a biodiversity payment.
This is the conclusion that we came to in the Climate Innovation Lab's new report for the Biological Heritage National Science Challenge.
So, in the same way that forests are paid to sequester carbon, a native forest could be paid for the biodiversity value it produces.
Ideally, that payment would also be extended to other kinds of "nature-based solutions" like wetlands, riparian restoration, estuaries, coastal habitats, mangroves, kelp forests, and so on.
But for forestry, it would immediately help to address the current disadvantage relative to pines.
A biodiversity payment could be funded by hypothecating the auctioning revenue from the ETS, or potentially by an environmental footprint tax, as proposed recently by the Tax Working Group.
This would help to create an economy of scale for nature-based forestry to overcome current cost barriers.
Because ultimately I think that new native forests should be actively managed for high-value timbers from selective harvesting, so that they can pay for themselves.
Projects like the Tōtara Industry Pilot in Northland show that, in the right context, there is a viable business case for native timbers.
This will require patience and support, to be sure, but then we're on the way to balancing climate and biodiversity gains with positive socioeconomic outcomes.
The commission noted that current settings under the ETS might incentivise more large-scale pine plantations than was actually desired to meet 2050 targets - and this could lead to forestry displacing gross emissions reductions. How might this hurt our climate change efforts?
It means that we're falling behind the curve on the low-emissions transition. It means that we're prolonging our dependency on fossil fuels, and so leaving ourselves exposed to future supply shocks and volatility.
It means we're missing out on the commercial opportunities to sell climate solutions to the world, and also the knowledge spillovers that come with research and innovation.
It means we're cementing our reputation as a laggard, with associated risks to market access and diplomatic relations.
It means we're leaving the next generation with a morass of deferred decisions and critical infrastructure needs.
And I'm also worried that we're endangering our national social cohesion, because rural communities are basically being asked to endure massive land use change with associated impacts on their communities and economies, all so that city folk can clog up the motorways in their SUVs for a few years longer.
As I said earlier, it's just bad strategy.
Are there any countries you feel that have their forestry settings right, and that New Zealand could learn from?
I think there are countries that we can learn from in terms of forestry generally, in the silvicultural sense.
The central European countries are worth learning from in terms of nature-based forestry, and it's interesting to see Ireland move in that direction too, because of similar controversies over clear-felling that we've had here.
But not many countries have integrated forestry into climate policy to the extent that New Zealand has, so, the lessons might be learned in the other direction, both good and bad.
Actually, it feels like the growing scepticism internationally toward mass tree planting campaigns and offsetting is a repeat of debates we've had here in recent years.
Besides sucking carbon dioxide out of the atmosphere, what other benefits does more forestry bring?
As I've said, trees and vegetation are critical for climate adaptation, such as water regulation, erosion control and reducing sedimentation.
And this doesn't necessarily mean blanket planting, but rather weaving trees into agricultural landscapes, especially gullies, waterways and erosion-prone slopes.
But forestry is also the only major industry that literally makes money from removing carbon dioxide from the atmosphere.
If we can substitute wood for high-emissions materials, then there's a double-gain, because we're getting negative emissions from the timber production, and we're getting avoided emissions by replacing other materials.
Cement production is the source of about 8 per cent of global CO2 emissions. Iron and steel are about 6 per cent.
So if we can swap out tilt-slab construction for mass timber, especially to meet housing and urban development needs, then we're really onto something.
And then there are the broader opportunities of the bioeconomy, which Scion is doing a lot of work on, where we're moving away from plastics and fossil fuels to renewable materials from planted forests like biopolymers and biofuels.
It's exciting stuff.
In many ways, I think we'd be better off to get these things right, then treat carbon sequestration as a co-benefit.
The Industry Transformation Plan for Forestry and Wood Processing that the Government is currently developing is a great opportunity to take a holistic view of the forestry sector and get some of this right.
Sometimes climate policy is best when it's indirect, when its leveraging off other benefits.
If we have a flourishing forestry sector which enjoys strong social licence, then the forests will get planted and looked after too.