Accelerating landscape scale restoration of native forest

Project Status: Current

Introduction

Tāne’s Tree Trust (TTT), in partnership with Trees That Count (TTC), is developing a nationwide network of demonstration sites to test and promote ‘seed islands’ as a method to accelerate large-scale native forest restoration.

The approach involves planting small groves of key native tree and shrub species within degraded landscapes including marginal, erosion-prone hill country so they act as seed sources that promote natural regeneration towards appropriate high native forest over time.

Representative sites have been established across New Zealand in collaboration with landowners, iwi, community landcare groups, NGOs, local authorities and other partners. Successful outcomes depend on integrating planting with effective pest control, including browsing animal management, targeted exotic weed removal and, where possible, bird and seed predator control.

Project objectives

The project comprises the following key components and aims:

1. Establish demonstration areas of planted seed islands using selected native trees and shrubs on representative landscapes to accelerate native forest succession.
2. Collaborate with existing restoration initiatives where the seed island concept has been applied but not formally monitored or documented.
3. Identify optimal sites for establishing seed islands to maximise performance, ensure accessibility for monitoring, and facilitate ongoing maintenance.
4. Implement seed island plantings at each demonstration area, testing a range of site conditions and vegetation cover treatments.
5. Undertake targeted pest animal and weed control including browsers and, where practical bird predators, in collaboration with project partners to promote natural regeneration.
6. Engage with other practitioners involved in native forest establishment to exchange knowledge and align efforts.
7. Disseminate early findings through social media, online platforms, workshops and wānanga with local communities, iwi, landowners and management agencies.

Status of seed island set up

Thirteen seed island sites are in various stages of establishment and monitoring from Northland to Southland, comprising five main demonstration sites and eight satellite sites. Of the demonstration areas, three are in the North Island and two in the South Island, representing marginal and degraded landscapes where large-scale native forest restoration is a priority, along with other key sites such as riparian zones. These are intensively managed and monitored for early performance. Satellite sites extend the project’s reach, building on existing work with landowners and community groups, and require less intensive planning and monitoring.

Main Demonstration Seed Islands

Five sites have been planted and are being monitored:

1. Northland – Waipoua Forest Trust, Pukemiro Ridge: Restoring cleared land bordering Waipoua Forest to protect and expand kauri. Baseline completed.
2. Bay of Plenty – Kōkako Ecosystem Expansion Project (KEEP), Rangiuru: Multi-generational project supporting kōkako recovery. Baseline and first-year assessments completed.
3. Banks Peninsula – Mount Vernon Park, Christchurch: Conserving and enhancing natural environment with public recreation. Baseline completed.
4. Central Otago – Remarkables Station, Queenstown: 900ha QEII covenant gifted by owners, located near Remarkables ski field. Baseline completed.
5. Tairāwhiti/East Coast – Pihitia Station, Pouawa: Adjacent to Pouawa River catchment flowing to Te Tapuwae o Rongokako Marine Reserve.

Satellite Seed Islands

Several sites are in various stages of planning, planting and monitoring:

1. Waikato – Kawhia: Two backdune areas planted over two years; monitoring and maintenance underway.
2. Tairāwhiti – Waingake Restoration Area: Catchment cleared of pines; monitoring planned for seed islands planted within regenerating shrubland.
3. Eastern Taranaki – Mānuka planted at wide spacing; seed islands of canopy trees planned for planting in 2025 or 2026.
4. Southern Hawke’s Bay – Mangarara Station: Two 10ha retired hill country blocks with manuka; seed islands to be planted in 2026.
5. North Canterbury – Tūhaitara Coastal Park: Tōtara and nurse shrubs in former pine backdunes; monitoring underway.
6. Southland – Te Kōawa Tūroa o Takitimu: Planting to replace exotic grassland with native seed sources, enhancing ecological and mahinga kai values.

Methods for Establishing Seed Islands

While consistency is important, the design and implementation remain flexible to accommodate:

• Site-specific variation in landscape and ecological characteristics
• Scale of planting
• Regional differences in suitable native species
• Local best practices for planting and early management

Seed island size is determined by the available gap or micro-site for inter-planting natives, or by the planting density where a nurse cover already exists. All sites are monitored using the standard plot-based procedures developed by Tāne’s Tree Trust and Trees That Count.

Early performance

Survival and growth assessments at most planted seed island sites to date show high survival rates and good early height growth for both native shrub and tree species. Examples of early performance are provided from one main demonstration site in the North Island and another in the South Island.

Kōkako Ecosystem Expansion Project (KEEP), Bay of Plenty

The second-year remeasurement of eight monitoring plots at the Rangiuru Te Puke seed island site, undertaken with the landowner and Bay Conservation Alliance’s new manager, shows:

• Exceptional survival and growth, despite the exposed ridge location
• Many five-finger, tī kōuka (cabbage tree), and mānuka seedlings have exceeded 2 m height within two years of planting
• Minor wind damage, with a few mānuka toppled
• Effective weed control has resulted in few aggressive weed species competing with the planted natives establishing within the dense pasture cover
• Projected 80% canopy cover within a further 2–3 years

Plans are now underway to interplant canopy species (e.g. tōtara, pūriri, kauri) in sheltered gaps within the developing nurse cover of native shrub hardwoods that are providing side shelter on this exposed site. ​​​​​​​

Mount Vernon Park, Port Hills, Christchurch

A full remeasurement was undertaken one year after planting for the 10 seed island plots established within this highly popular public recreation park, established on steep pastoral hill country typical of the Port Hills. Initial observations from the assessment found:

• Good survival on the low, sheltered sites compared to the seed islands located on the high exposed ridge and western faces
• Good weed control in the 3-6 months after planting has been undertaken. Without weed control and the use of stakes to help locate the planted natives some of the smaller seedlings would likely have been suppressed by exotic grass and gorse regrowth
• Frost damage has affected some of the more vulnerable species such as tōtara, and the coprosma species
• Browse damage was evident on some highly palatable species, e.g. tī kōuka

Promotion

Over the past 12 months, the seed island project has been promoted at several events with positive feedback on the concept. Highlights include:

• Presentations by Tāne’s Tree Trust at Te Uru Rākau – New Zealand Forest Service nationwide workshops for farmers, foresters, landcare groups, iwi, communities, schools and the public on large-scale native afforestation, including seed islands.
• Regular updates to Trees That Count Regional Advisor meetings.
• Project update on the Trust’s website https://www.tanestrees.org.nz/projects/accelerating-landscape-scale-restoration-of-native-forest/.
• Conference presentation at the Coastal Restoration Trust’s Annual National Conference in Tolaga Bay, Tairāwhiti, attended by 140 participants including community groups, iwi, councils, research providers, landholders, Māori trusts, consultants and practitioners.

• TUR presentation on the seed island concept was presented at the New Zealand Ecological Society Conference (Rotorua, November 2024), comparing it with seed orchards. Developing seed orchards to provide genetically improved seed of natives will require major research and consideration of cultural and ecological impacts. Seed islands are a more practical, cost-effective option for large-scale native afforestation.
  https://www.mpi.govt.nz/dmsdocument/64956-Native-Afforestation-Programme-Feasibility-of-a-network-of-seed-orchards-vs-seed-islands.

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