Introduction

Tāne’s Tree Trust were commissioned by Mānuka Farming NZ Ltd to collaborate in a feasibility study funded by Te Uru Rākau (TUR) – New Zealand Forest Service to assess the viability of establishing native tall tree seed orchards and seed islands in New Zealand to support native afforestation efforts. A report was completed during 2024 and can be downloaded from the TUR website.

Content and context

Seed orchards and seed islands are two distinctive approaches to increase overall populations of particular native species. Simplistically, seed orchards are higher-cost, actively managed enterprises that prioritise commercialisation and genetic improvement over biodiversity and ecological restoration, whereas seed islands are lower-cost undertakings that assist with the restoration of biodiverse native forest. Both strategies offer unique advantages and use of either does not preclude the other for any one species.

A successful seed orchard programme requires significant long-term planning and security of funding for both establishment and maintenance, while seed islands can be more easily implemented and only require some ongoing monitoring and maintenance to increase seed island success.

Where resources are limited and where commercialised genetic tree improvement is less important, identified seed stands or planted genetic archives may suffice for seed production. In this case, maintenance of genetic diversity is deemed more important than genetic gain, although selection of important traits such as disease resistance may still take place.

In a comparison of seed orchards and seed islands, the report discussed:

• The historical and ecological context of New Zealand’s native forests;
• Seed production and genetic considerations; and
• Māori perspectives and cultural considerations.

Seed islands

Seed islands were considered a natural and cost-effective solution to support native afforestation efforts at scale. They leverage natural regeneration processes, mimicking the way forests naturally recover and expand. This approach is ecologically sound and cost-effective, needing minimal human intervention and resources in comparison to the intensive management seed orchards require. Seed islands promote biodiversity by creating interconnected habitats and preserving genetic diversity, crucial for the long-term resilience of native forests. While seed island field trials are underway, there is currently limited data to draw from. However, the early evidence suggests that the benefits of seed islands are likely significant.

Seed orchards

Seed orchards were considered a potential long-term investment but with uncertainties. Seed orchards offer the potential for producing large quantities of genetically improved seeds. This may prove transformative in relation to the development of a larger scale commercial native timber industry. However, seed orchard establishment and maintenance demands substantial financial investment, specialised knowledge, and ongoing research. It is unlikely that there is current economic or market justification to establish native seed orchards in New Zealand, as part of intensive breeding programmes. However, there are more cost-effective alternatives to creation of seed orchards, including management of seed stands or creation of genetic archives, which can be used to provide seed, and preserve genetic material, as described in the report.

The potential scope of improvement possible in a breeding programme for any given native species cannot be quantified at this stage. Development of a sustainable commercial market for native timber (and hence for the seeds of any particular species) are contingent on multigenerational investment by both the public and private sectors. There are considerable uncertainties associated with native, tall-tree seed orchards.

Conclusions

Both seed islands and seed orchards have their merits. However, seed islands are a more practical, cost-effective, and feasible solution to encourage native afforestation at landscape scale. Seed islands should therefore be prioritised, while the economic and policy implications of seed orchards are studied further (if desired). This way, New Zealand can achieve significant ecological and environmental benefits while laying the groundwork for future advancements in native species management, reduction in net greenhouse gases, increased ecosystem services, and promotion of cultural values and sustainable land use.

For more information contact:

• TTT Office [Enable JavaScript to view protected content]