Response: Plant a billion trees – but mostly exotic plantation forests
Slash: Cyclone Gabrielle (scroll down to video 1 toplay the documentary with sound)
Balancing the carbon budget: becoming ‘net zero’
Taking too much carbon out of the ground and burning it to fuel our modern lifestyles, and converting vast areas of the planet from carbon-absorbing forests to carbon-emitting intensive agriculture, is changing the comfortable climate that supported us for 10,000 years. While we can’t undo many of the changes now underway, we can reduce the impacts and adapt to what’s coming, by:
- Reducing our carbon spending: rapidly transition from fossil fuels to renewable energy and move from outdated intensive agriculture.
- Saving carbon: enable terrestrial and oceanic ecosystems to capture carbon and store it underground. Often called
‘drawdown’ or ‘sequestration’ the single best way to do achieve this is, is to protect and restore natural ecosystems. (Technology cannot achieve this with a fraction of the efficiency, cost, and certainly not at scale).
New Zealand Carbon Farming, one of the country’s biggest landowners, plants radiata pine for carbon credits, then sells these credits to large fossil fuel polluters, most of which are outside New Zealand, to offset their company’s carbon emissions. The company states that the pine won’t be harvested and sold for wood, rather, it will serve as a nursery crop for native forests. The NZ Climate Commission notes that this could take centuries. Meanwhile, radiata pine forests can cause a multitude of problems (see below). This ‘hybrid’ model may rapidly draw down carbon from the atmosphere, but there is an urgent need to restore ecosystem services to help us mitigate and adapt to the impacts of climate change.
The ‘One Billion Trees’ Project: what it really meant
Natural regeneration is occurring on Banks Peninsula on a massive scale, but because it is not financially incentivised we increasingly see large areas destroyed by aerial spraying as landowners perceive native vegetation or its nurse canopy as an invasive weed affecting income rather than carbon sequestration with potential to earn income. We submit that this is utterly counterproductive to the goals of the Climate Change Response Act. At best carbon sequestered in these naturally regenerating areas is not being included on the national register, at worst it is being replaced with methane emitting pastoral farming. Although we are Banks Peninsula focussed, we are aware of the same issues around the country. – Submission to the Parliamentary Select Committee hearings for the Climate Change Response (Emissions Trading Scheme) Bill, February 2020
While the title was inspirational, the ‘billion’ number was misleading as it included replacing existing commercial exotic forestry, 50% of which was due to be harvested and in need of replanting just to maintain existing commercial forestry levels. The other 50% was intended to be a mix of more plantation forestry and native trees.
So ‘one billion’ trees really meant around 500,0000 additional trees.
That’s still a lot of carbon-absorbing trees, right?
No, not if the true carbon cost of harvesting exotic trees, lost ecosystem services, lost soil carbon, lost life-supporting ecosystem services are accounted for.
Data from Tāne’s Tree Trust Indigenous Plantation Database show that:
..munched on by insects and exposed to microbial bugs in the soil, invading species released 2.5 times the carbon dioxide from the soil into the atmosphere, compared to natives. Lincoln University researcher Dr Lauren Waller said the exotic plants interact very differently with the animal and soil microbes around them. The difference in carbon release was thought to stem from the introduced plants’ ‘higher-quality and quantity’ leaves. ‘These were more palatable to insect herbivores, and sped up rates of decomposition by soil microorganisms such as bacteria and fungi,’ she said. – Stuff, 2020
- Carbon sequestration for planted [native] forests of totara, kauri, kahikatea, rimu, other conifers, puriri, beech, and other broadleaves is in the range:—10.0 to 16.4 tCO2 ha-1 yr-1 (mean annual increment over 50 years) and —18.2 to 29.9 tCO2 ha-1 yr-1 (current annual increment at age 50 years)
- Growth rates of these native tree species increase steadily over the first 50 years achieving higher productivity as well as carbon sequestration with age.
- Radiata pine in New Zealand (mean annual increment is 21 to 27 tCO2 ha-1 yr-1 for radiata pine at age 50 years).
Exotic forestry: the real costs and risks
“The forestry sector in Canterbury was deemed to be at extreme risk of extreme weather events, such as storms and high winds, and increased fire weather, and at major risk due to higher mean temperature. This is confirmed by research finding that the forestry sector is at risk from increased fire incidence, expected losses in soil carbon (mainly due to the increase in air temperature), and indirect risks due to increased incidence of pests and diseases (Landcare, 2019). There is also a cascading risk on soil erosion due to the impacts of drought, extreme weather events, and high winds on forests (particularly exotic forests).” – Canterbury Climate Change Risk Screening Interim Report
This exposes those investing in plantation forests to a very real situation where they will be liable for re-paying carbon credits for any damages or losses. The increasing chance of fire, wind, disease, or heat stress will increase as the climate changes and insurance companies subsequently opt to decline insurance.
Financial costs
No detailed budget analysis was ever undertaken as to the viability of the one billion trees project. This is because there were (and still are) complex fiscal, accounting, and design implications in terms of the location, scale, and purposes of tree planting, and the uncertain future of carbon prices under the Emissions Trading Scheme. The value of harvested forestry also is uncertain, given the Bonn Challenge to restore 350 million hectares globally by 2030 will likely result in a global oversupply of plantation forest products in coming decades. One option, to burn the slash and/or plant pine as a dedicated biofuel, capture the CO2 emitted and store it underground (known as BECCs) raises major concerns. The financial and carbon costs of harvesting, transporting, and processing slash for bioenergy also needs to be considered.
The carbon cost
Wood products are often regarded as ‘carbon neutral’. In reality, the true life-cycle carbon cost is ignored by the forestry sector as it’s virtually impossible to calculate. These costs include the carbon-emitting heavy machinery cost of harvesting, shipping—mostly to China—and converting wood into products, which are then transported around the globe. Most of the carbon stored in those wood products, whether it’s paper or houses or furniture, eventually ends up burned or rotting in land fills, releasing the carbon back into the atmosphere instead of permanently locking it away.
Climate change risks: wind, higher temperatures, drought
There are serious and urgent questions about the financial viability of planting exotic tree species that may not survive predicted changes to our climate over the coming decades (Fig. 3).
“We find that subsequent droughts generally have a more deleterious impact than initial droughts, but this effect differs enormously by clade and ecosystem, with gymnosperms and conifer-dominated ecosystems more often exhibiting increased vulnerability to multiple droughts.” – Anderegg et al (2020)
Climate change risks: floods and soil erosion
One key reason for planting trees is to reduce the impacts of floods and soil erosion. But as the climate changes, alpine-fed rivers are likely to flood more frequently. The preferred method of harvesting plantation blocks in New Zealand is to clear the entire block, leaving nothing but ‘slash’ behind, making the land highly vulnerable to floods and soils erosion (Video 1).
“…The East Coast is experiencing widespread environmental and community damage from forestry slash during the last three consecutive winters. Millions of tonnes of logging debris have been washed down onto 3 farmland, rivers, shoreline, beaches and into marine environments. Piles of debris were strewn across properties, and had knocked some houses off their foundations, covered farmland, blocked waterways, damaged bridges, clogged beaches and spoiled marine areas.” – Overseas Investment Amendment Bill (No 3) Select Committee Submission
Climate change risks: wildfires
There is an increasing risk of wildfires, particularly from pine and eucalypt forests that contain volatile flammable compounds. These compounds become more concentrated as the climate grows warmer and dryer, making the trees even more flammable.
In the South Island, there is rush is to plant exotic species that have much higher potential for mega fires. Meanwhile, wilding pines that continue to spread at an alarming rate (see below) were directly implicated in the 2020 Mackenzie fire.
Pine forests are particularly flammable, as their needles and resin are both highly flammable, and extreme heat and drought make them more likely to ignite.
Pine forests leading to an increase in atmospheric methane?
Methane is a potent greenhouse gas, and the amount in the atmosphere is rising rapidly. The volatile compounds produced by pine forests (which give them their distinctive smell and make them highly flammable) remove chemicals that help break down atmospheric methane. In short, while pine forests may mop up carbon, they may lead to an increase in methane, a far more potent greenhouse gas.
Our native ecosystem soils are often overlooked when it comes to storing carbon, but the Earth’s soils contain about three times the amount of carbon than what’s in the atmosphere and four times the amount stored in all living plants and animals. The soils of pine forests that have replaced native hardwoods in Germany do not sequester nearly as much methane as native forests.
A race against time: sacrificing biodiversity and our climate beyond 2050, to reach net zero (in accounting terms but not reality) before 2050
As Charlie Mitchell points out in this article, the question of planting natives versus exotics is a ‘rabbit vs hare’ problem. New Zealand is committed to achieving net zero emissions by 2050. That’s less than the lifetime of plantation of exotic radiata pines. University of Canterbury forestry lecturer Dr Euan Mason estimates that because natives are too slow growing, to meet this accounting commitment and limit the impacts of climate change, we need to plant 5 billion of these fast growing pines (Fig. 4). And because the climate already is passing dangerous tipping points, we need to drawdown carbon dioxide as fast as possible.
Since the 2012…over a hundred thousand hectares of true land-use change [has been] going on around wetlands, scrub being cleared, and dairy land-use intensification. – Landcare Research, 2020
Even the most egregious offences – including a dam built on a wetland, clearance of a nationally endangered form of kānuka, and aerial poisoning of swathes of regenerating native bush – often prompted little more than a warning from authorities.” – Charlie Mitchell, Stuff, Oct. 2020
The Forest Owners Association estimated that upwards of one million hectares of New Zealand’s 1.7-million-hectare plantation forests were either directly owned or managed by foreign interests. This means that the value of carbon credits in these forests is not being used to offset New Zealand’s emissions.
Modelling by the Parliamentary Commissioner for the Environment estimates that an extra 2.6million ha. of forestry will be needed by 2050 plus an additional 2.8million ha. by 2075 just to maintain NZ at net zero. Moreover, a second report from the Parliamentary Commissioner for the Environment (October 2022) calculated that
7.7 million hectares would be needed to offset biogenic methane.
Currently, around 45% (12.1 million ha.) of NZ’s land mass is agricultural. Over the past 2 decades the trend has been to remove trees and convert farms and native ecosystems into intensive, industrial scale dairy farms requiring investment irrigation, which has led to a (still ongoing) rapid decline in waterways and destruction of wetlands.
In places like Canterbury and Southland, planting exotics is vastly outnumbering native species (Fig. 3). At the same time right across New Zealand, native forests, grasslands, and wetlands continue to be ‘under attack’ with offenders facing little consequences.
The problems with burning forests for fuel — biofuels & BECCS
BioEnergy Carbon Capture System or BECCS is favoured by the IPCC in its modelling. It means planting vast areas of fast-growing monoculture trees like radiata pine, cutting them down, burning them for bioenergy, capturing the CO2 emitted by burning, and storing that CO2… somewhere. That ‘somewhere’ presents problems (see ‘negative emissions technology‘ this website).
You can’t easily wrap up 40,000 million tonnes of anything and just pop it away in a downstairs cupboard every year. – David Borlace (Video 2)
In some countries, the captured CO2 is sold to oil companies that use it to to force out the last few drops of oil from depleted wells. This is called Enhanced Oil Recovery. Because these companies are pumping CO2 into the ground, it’s regarded as negative emissions technology and gives them enormous tax breaks and carbon credits, even while they sell the recovered oil, which is burned for energy, releasing yet more CO2 back into the atmosphere.
Even based on that stunningly flawed rationale, for BECCS to successfully offset our emissions based on the current system of carbon accounting (assuming the CO2 can be safely stored underground), it would require fast growing monoculture crops to replace much of the existing native forests on the planet by 2100, around 25-46% of the land currently used to feed people (Video 3).
Bioenergy with carbon capture and storage is expected to capture, on average, around 130 billion tonnes of carbon via planting crops for biofuel that are then burnt in power stations…. It is expected that an additional area of one or two times the size of India is needed for bioenergy crops by 2050. My colleagues and I find that expansion of bioenergy in order to meet the 1.5C limit could cause net losses in carbon from the land surface. Instead, we find that protecting and expanding forests could be more effective options for meeting the Paris Agreement. – Dr Anna Harper, University of Exeter
We found that in a majority of the areas where forests will be replaced, more carbon is stored by keeping the forests. – Smolter and Ernsting
While New Zealand is considering only using waste wood for biofuel. For that waste to exist it requires a forestry industry to support it and/or to import it.
In Canterbury, the conversion of forestry to dairy farming over the past few decades has ensured there is insufficient biomass to enable cost-effective conversion from fossil fuels to biofuels.
In the South Island, there is more than enough harvestable plantation biomass to replace all the current heat demands from fossil fuels. In 2021, the projected potential energy, harvestable from wood fibres (biomass), across the South Island was 60 PJ. Once the current domestic demand and efficiency of wood fibres to produce heat was considered, the realistic potential energy availability was 32 PJ. This would have been more than enough to replace the 2021 heat production demands (24.3 PJ) created from fossil fuels.
However, the cost of transporting wood fibres plays a prominent role in the economic viability of biomass. Transport distances greater than 100km from forest landings are often uneconomical, almost doubling the cost of our cheapest biomass resource. Consequently, biomass use is limited to the region in which it is harvested. – DETA, 2022
Wilding pines (including radiata pine): the wrong tree in the wrong place
…lose $4.6 billion in productivity through reduced water available to farmers and hydro-electricity schemes over the next 50 years, and through more money needed for forest fire prevention—or save the economy $5.3b over 50 years, by getting on top of the wilding pine problem and freeing up more productive land. – MPI report to 2019 NZ Budget
New Zealand has an unenviable history of planting conifer forests in unsuitable and/or inaccessible terrain subject to excessive erosion (see Video 1). Many species of conifers have self-seeded on prime agricultural lands and displaced globally rare ecosystem including tussock grasslands that, combined with associated wetlands and peatlands, can sequester higher levels of eCO2 than these conifers. These trees also remove water from catchments already depleted by intensive agricultural practices, and they destroy the hydrology of rivers, leading to floods and erosion. Further, they’re exacerbating fire risks at a time when vastly more resources are needed to combat the growing number and intensity of forest fires each year. So while it’s true that mature wilding conifers do absorb CO2 , they currently cover more than 1.8 million ha of land, causing economic losses in the billions and displacing native species and entire ecosystems that provide(d) essential services that are needed in the face of a changing climate. In spite of $11 million every years spent to control them, they’re spreading at an estimated rate of 5% annually.
At that rate, not including the added impact of planting five times as many conifers needed to balance New Zealand’s carbon budget, 20% of NZ will be covered in wilding pines, while the original forestry block owners that planted them are not liable for their costs.
Professor Euan Mason states that radiata has a ‘…superpower, growing fast and hoovering carbon dioxide while it’s still young, leaving other trees in a cloud of wood-chip.’
When a few individual radiata pines are left following plantation harvesting, they attract birds that carry and in turn drop seeds of native species. New growth of native forests spread out from around these solo mature radiata, and in places where high winds have felled them, they often serve as protective nursery areas for native samplings to take hold. One argument is that, strategically placed radiata might help NZ meet its 2050 obligations and then act as a nursery for natives to drawdown CO2 beyond 2050. However, recent research (August 2022) indicates that radiata pine is far more invasive that previously thought, and poses a major economic risk.
In sum, too much emphasis is being placed on the value of radiata pine over natives. Under the ETS, owners of wilding conifer stands that meet the criteria of a post-1989 forest can register for carbon credits without any obligation to manage the spread of wildings.
