Nature-based solutions: Native forests
Beech forest Nina Valley image: Sonny Whitelaw
Native forestsThe problems
“Restoration of forest cover is widely considered the most viable near-term opportunity for carbon removal. Unfortunately, some of this enthusiasm has been used to promote plantation forestry—growing trees of a limited variety of ages and species (for example, in monoculture plantations) does not have the same carbon benefits as maintaining an intact forest ecosystem.” – Girardin et al (2021)
The Emissions Trading Scheme makes it more financially lucrative to plant exotic monoculture forestry, primarily environmentally destructive monoculture plantations of radiata pine, than restoring native forests. This ignores reality: carbon stored in native forest soils vastly exceeds carbon in the soils of monoculture pine forests. And biodiverse native forest store just as much if not more carbon above the ground, while also providing life-supporting ecosystem services.
Worse, there is an impetus to replace native forests, threatening our ability to mitigate the impacts, adapt to climate change, and retain essential ecosystem services. Some of the risks were identified in the 2020 report to the Canterbury Mayorial Forum:
“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
“The large area of existing native forests in Aotearoa/New Zealand means native forest is central to our ability to address the ongoing biodiversity crisis and also assist with addressing the emerging climate crisis. Despite this, there is currently a profound lack of financial and technical support to assist owners’ management of existing forest. For instance, funding offered to target erosion control is common among Regional Councils, yet as these sites are already forested, existing forests do not qualify.” – Forbes (2020)
“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, Feb. 2020
The solutions
“Native species growth data amassed over many years by Tāne’s Tree Trust is the best available, and shows that, over the longer term and even in the medium term, (New Zealand) native species can compete with exotic species in terms of carbon removal and storage.” – PureAdvantage (Video 1)
“The essential and critical physical management actions that need to be supported following an ecosystem management approach are:
- Fencing to exclude domestic stock,
- Management of feral herbivories, implemented at a community scale,
- Management of other pests, e.g., invasive vines and shade tolerant weeds,
- Enrichment planting to address stalled successions and local species extinctions. – Forbes (2020)
Restore degraded native forests using the same strategies listed above.
Replace lost forests:
“Establishing close to 300,000 ha of native forests could cost between $5 billion and $15 billion. The carbon benefits alone could outweigh the establishment and maintenance costs after a few decades. This return could be achieved in as short as about 15 years for reverted forests or as long as about 70 years for higher cost planted forests. Native forests also provide a range of benefits.” – Climate Change Commission 2021
There are several ways to achieve this cost-effectively, depending on the location and circumstances:
- Natural regeneration on agricultural lands adjoining intact forests, particularly when using gorse as a nursery plant (Videos 1, 2 and Fig. 2).
- Incorporate mix of non-wilding hardwoods exotic hardwoods with natives, to offset the high costs associated with restoring native forests
- While small scale, create microforests using the Miyawaki method. This is a great process for small groups and communities to plant biodiverse natives forests in urban areas, for example, the Nelson Whakatu Microforest (this website).
The problems with radiata pine
Radiata pine grows fast, is an invasive species that escapes plantations, is a valuable export product, and is regarded as a lucrative form of ‘carbon farming’, that is, a fast way to capture carbon from the atmosphere and sell carbon credits to carbon polluting industries under the emissions trading scheme (ETS). The government’s billion trees project (covered in more depth in this website) supported the commercial forestry industry that largely grows radiata pine, while vastly under-funding native forests. Perversely, the ETS uses a selective accounting system that doesn’t account for the staggering losses of soil carbon and lost ecosystem services caused by radiata pine plantations.
These damages and losses lead to an increase in carbon dioxide emissions (Fig. 3). The ETS also does not account for the carbon cost of cutting down trees, transporting the logs, and converting them into wood products, most of which will eventually end up in landfill or burned, releasing the carbon back into the atmosphere in a system known as bioenergy carbon and capture (BECCs). Non-native forestry also pose increasing financial risks to investors, including a rapidly growing risk of forest fires as temperatures rise, and droughts as the rate of evapotranspiration increases.
“In a thriving forest, a lush understory captures huge amounts of rainwater, and dense root networks enrich and stabilize the soil. Clearcutting removes these living sponges and disturbs the forest floor, increasing the chances of landslides and floods, stripping the soil of nutrients and potentially releasing stored carbon to the atmosphere. – Jabr, The Social Life of Forests, 2020
Production forests are typically clear-felled. (mage: PureAdvantage (Video 2)
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 1)
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, pumping 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 2).
“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.” – Whitelaw, 2022
“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
