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Ecosystems: Our native forests

Ecosystems: Forests

Beech forest Nina Valley: image – S. Whitelaw

Our native forests

Summary

 
  • According to economists, trees are one of the world’s most cost-effective carbon sinks.
  • From 2019-2020 the global destruction of old-growth tropical forests alone increased 12%. That’s 10 million acres, an area roughly the size of Switzerland, adding more than 2.5 billion metric tons of carbon dioxide to the atmosphere, or about twice as much as is all the cars in the US every year. – World Resources Institute.
  • In 2010, Aoteaora had 9.65 million hectares of natural forest covering over 43% of our land area. In 2020 alone, we lost 8,530 hectares of this natural forest.Global Forest Watch.
“New Zealand’s forests among the most significant stashes of carbon that need urgent protection if the world is to have any hope of limiting temperature increases to 1.5 degrees Celsius or 2C.” – Goldstein et al (2020)
 
“New Zealand’s forests and other land areas may be absorbing up to 60% more CO2 than has been calculated, with much of this uptake likely occurring in native forests.”NIWA (2017)
 
Countries that will incur the greatest economic damages from climate change stand to benefit the most from conservation of tree diversity… Our results emphasize an opportunity for a triple win for climate, biodiversity and society.” –  Mori et al (2021)
 

Beech forest Nina Valley: image – S. Whitelaw

Our native forests

Summary

 
  • According to economists, trees are one of the world’s most cost-effective carbon sinks.
  • From 2019-2020 the global destruction of old-growth tropical forests alone increased 12%. That’s 10 million acres, an area roughly the size of Switzerland, adding more than 2.5 billion metric tons of carbon dioxide to the atmosphere, or about twice as much as is all the cars in the US every year. – World Resources Institute.
  • In 2010, Aoteaora had 9.65 million hectares of natural forest covering over 43% of our land area. In 2020 alone, we lost 8,530 hectares of this natural forest.Global Forest Watch.
“New Zealand’s forests among the most significant stashes of carbon that need urgent protection if the world is to have any hope of limiting temperature increases to 1.5 degrees Celsius or 2C.” – Goldstein et al (2020)
 
“New Zealand’s forests and other land areas may be absorbing up to 60% more CO2 than has been calculated, with much of this uptake likely occurring in native forests.”NIWA (2017)
 
Countries that will incur the greatest economic damages from climate change stand to benefit the most from conservation of tree diversity… Our results emphasize an opportunity for a triple win for climate, biodiversity and society.” –  Mori et al (2021)
 

The 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 impetus to replace native forests—which store massive quantities of carbon dioxide in theirs soils as well as in living trees—with environmentally destructive monoculture plantations of radiata pine, poses an escalating danger, threatening our ability to mitigate the impacts and adapt to climate change and to 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

Fig. 1: Loss of natural forests in New Zealand in 2013 -2020 (Image: World Resources Institute).

“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

Fig. 2: On the Banks Peninsular, gorse (distinctive yellow flowers) is serving as a nursery plant for native forest regeneration. (Image: Happen Films)

The solutions

Aotearoa’s mature native forests alone still hold 7 billion tonnes of carbon dioxide equivalent – equal to 86 years’ worth of the whole country’s greenhouse gas emissions.

Protect all native forest remaining in Aotearoa. This includes identifying Significant Natural Areas on farmland to prevent their ongoing destruction (we lost 8,530 hectares of natural forest in 2020 alone.)

“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)
Video 1: O Tātou Ngāhere: Our forest. This video from PureAdvantage explores the multiple aspects of native forests and how they are being reintroduced to degraded agricultural lands.

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:

Video 2: Turning degraded agricultural land into native forests using gorse as a nursery crop.

The problems with radiata pine

Radiata pine grows fast, is a valuable export product, and 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 losses of soil carbon and ecological damage caused by radiata pine plantations.

Radiata pine plantations damage soil biodiversity, leading 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 and evapo-transpiration rates increase.

“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

Fig. 3: (Image: Nature)

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 3)

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 plus by 2100, around 25-46% of the land currently used to feed people (Video 3).

Video 3: BECCS: the bad, the really bad, and the really really bad.

Production forests are typically clear-felled. (mage: PureAdvantage (Video 2)

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.

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

Video 4: Biomass from forests is doing more harm than good.

“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

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