Turning marginal land into a protector for New Zealand biosecurity

Set amongst Hauhungaroa No 7, a 200-hectare block of Māori land west of Lake Taupō, the whenua is primarily used for dairy farming. A gully, however, had previously been identified as marginal land, and at risk of erosion. With a desire to protect and enhance the whenua the owners looked at retiring the land, but a new alternative emerged to utilise the area that would be both sustainable and have the potential to increase the return on the land.

Working with Te Tumu Paeroa and the Mānuka Research Partnership, a pilot mānuka plantation was developed with a focus on protecting our taonga and biosecurity in New Zealand.

At the start of the project, the following benefits were identified by the advisory trustees, (who act on behalf of the block's 684 owners), for developing the high value mānuka plantation:

• An alternative sustainable use of land.
• Erosion prevention through restorative planting of the gully from pasture to trees.
• An opportunity to increase returns on marginal land.
• Building capability and knowledge on mānuka plantations from block selection, planting requirements, pest control, business model to design and build, and ongoing management.
• An avenue to explore further opportunities – partnering with a beekeeping company to improve returns to owners and training opportunities.

Finding the potential for this block of land

The new land analysis tool, Taikura Nuku identified how Māori land like the Hauhungaroa No 7 gully can operate at ‘highest and best use’. The model combines Manaaki Whenua – Landcare Research datasets, geospatial data, industry benchmarks, and Te Tumu Paeroa land portfolio information. The analysis from applying the model supported decision-making about changing land use, helped to attract investment, and communicated the value of this parcel of Māori land.

What is a High Value Mānuka Plantation all about?

The high value mānuka plantation programme aims to move the industry from wild harvest to science-based farming of mānuka plantations. Seeds are sourced from areas that produce high-quality honey, and the focus is on increasing the yield and reliability of medical grade mānuka honey supply. High UMF mānuka honey (10+) is in demand because of its strong anti-bacterial properties.

The programme is led by the Ministry of Primary Industries, Comvita and the Mānuka Research Partnership.

Involving the community in the survival survey

The trustees worked with students from Toi Ohomai, Institute of Technology to conduct a survival survey. Spending a full day on Hauhungaroa No. 7, Resource Management students checked the plant survival rates. The results were exceptional, with the plantation averaging 1,135 stems per ha (the target was 1,100), and achieving a 96% survival rate.

Developing pest control practices to balance the needs of the plants and the whenua
Careful use of herbicide is critical in order to avoid damaging the mānuka trees. While it’s meant some weeds have not died off and weeds are growing back quicker, the mānuka survival rate means the trust is carefully balancing the needs of the plants and the whenua.

There's been some damage from a little leaf roller caterpillar that led to the loss of some trees, but the infestation was small and as the trees grow, the risk of significant damage to the trees reduces.

Rabbits and hares remain the largest threat to the plantation and active pest control measures have been planned to protect the trees.

There has been concern about Myrtle Rust but with only three mānuka affected out of the 19,163 mānuka trees inspected, the team is hopeful myrtle rust won’t impact mānuka significantly.

Close monitoring of the plantation continues.

The wider impact of this work

Typically, Māori land blocks like Hauhungaroa No.7 have limited options. If the mānuka plantation proves itself, not only will this result in increased economic returns, but also social, cultural and environmental outcomes. The legacy of this research has the potential to demonstrate that mānuka plantations are a beneficial alternative land use for Māori land.