Researchers say the study could unlock the trees' potential for a combined carbon-fixing and oil harvest regime.

The New Zealand study, published in the prestigious Lancet Group’s eClinicalMedicine Journal, was led by the Medical Research Institute of New Zealand in partnership with Hikurangi Bioactives and TRG Natural Pharmaceuticals.

It is the first clinical trial looking at the topical use of kānuka oil for eczema relief and showed that a topical cream containing 3% kānuka oil delivered a significant reduction in eczema symptoms compared to cream alone.

Kānuka is eligible for carbon credits under the ETS if grown post-1990 to at least five metres tall with canopy covering at least 30% of any area claimed.

Manu Caddie, co-founder of Hikurangi Bioactives Limited Partnership, which is based in the East Coast, says the trial results are “hugely exciting” and validated the healing properties of the taonga species. “Most clinically proven products aren’t from a natural source. So the study is a great step towards supporting this niche category of clinically-proven natural health products.”

Hikurangi Bioactives co-founder Manu Caddie.

Potential growth

He says kānuka is a viable alternative to permanent pine plantations on marginal land. “We’ve seen huge areas of kanuka quickly regenerate in Tairāwhiti and combined with honey production and now oil, there could be multiple benefits for jobs, returns to landowners, and biodiversity enhancement.”

While native trees are currently assigned fewer NZUs per hectare compared to pine, Caddie is hoping this will be reviewed. “I understand there may be some scrutiny of look-up tables for natives carbon sequestration rates to review the science they are based on, and also some consideration about how to recognise the broader social, cultural and environmental benefits - including soil conservation, freshwater quality and biodiversity - of incentivising natives.”

He says those benefits are often recognised in deals in voluntary carbon markets but not currently addressed in the ETS. “There are some good proposals for ETS reform to address these issues.”

Caddie believes that combining carbon farming with a sustainable harvest regime for oil and honey production could eventually be realistic alternatives to intensive animal farming or pine plantations. “But less intensive animal farming and smaller woodlots on land that is more suitable for those activities could also be viable alongside natives used for income generation.”

Kānuka can be long-lived, and is a valuable nursery crop for other natives. “There is some good science on mānuka and kānuka. Where mānuka is established, kānuka will often take over after the mānuka dies out over 30 to 40 years. Kānuka can last a couple of hundred years but it also supports other natives to come through and re-establish much larger species of podocarps,” Caddie says.

However harvesting foliage from mature kānuka can be challenging - especially if it has to be five metres tall to qualify for carbon credits. “There will also be issues around access for vehicles to transport harvested biomass to the closest extraction facility, so we expect landowners will designate some areas for kānuka harvesting and others for honey and regeneration of other natives.”

Kanuka grow well on the East Coast of the North Island.

Looking for suppliers in other regions

Caddie says the group is assessing what volume of kānuka biomass is currently available for sustainable harvest in Tairāwhiti. “Depending on the size of licensing deals for this product, we may need to look beyond Tairāwhiti to source oil from supplier partners in other regions.”

He notes that a successful clinical trial is just part of the equation. “The next big milestone is landing distribution deals with overseas companies that want to take the product into specific markets. TRG Natural Pharmaceuticals is currently in negotiations with a number of interested companies in North America, Europe and Asia, so we hope to have licensing deals secured by this time next year.”