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August 30, 2024
The Tīmata Method for Low-Cost Native Forest
Returning large areas of erodible land in New Zealand into native forest (ngahere) has long been a challenging and costly process, but a promising solution has emerged: the Tīmata Method for low-cost native forest establishment.
Many land managers across Aotearoa would love to retire some marginal or highly erodible land back into native bush (ngahere). However, the establishment of ngahere has long been a challenging and costly process, which limits private landowners' participation in large-scale projects.
A new report and information video, produced by the Our Land and Water-funded project Restoring Farmland into Ngahere, introduce the Tīmata Method for low-cost native forest establishment. The Tīmata Method has been demonstrated to be effective and significantly cheaper than conventional high-density / high-grade native planting methods, reducing the cost of establishing native trees by over one-third.
“Most farmers you talk to really do want to retire farmland into natives, but simply cannot afford $30,000 a hectare,” says the project lead Alison Dewes, director of environmental advisory company Tipu Whenua.
Dewes points out that New Zealand has about 1 million hectares of land that could be retired into natives. “The Tīmata Method represents savings of $20 billion across the country in achieving that.”
A Successful Low-Cost Native Planting Method
The Tīmata Method – which from te reo Māori translates to begin, start, kick-off, or commence – initiates natural processes that are known to restore ngahere. Using this method to retire farmland into ngahere has the potential to reduce the cost of establishment by some $20,000 per hectare.
This equates to a potential saving of $10 billion if even just half of the 1 million hectares identified as highly erodible pastoral land were planted back into native forest using this method, says Dewes.
In the Hawke’s Bay, around 200,000 hectares are suitable for replanting – the erosion-prone nature of the land sadly highlighted by the devastation of Cyclone Gabrielle.
The Tīmata Method imitates the natural reversion process, where kānuka and mānuka are planted at lower densities, acting as a nursery crop for succession trees to establish in the future. The method relies on careful land preparation, the use of easily propagated native nursery crop species, cultivation of plants in small-size containers known as forestry-grade, and fewer trees per hectare than conventional guidelines.
To date, around 10,000 ha of planting across NZ has been trialled using this method, and is reinforcing that the Tīmata Method lowers cost and makes more efficient use of time and labour resources.
This video shares elements of the method for low-cost, broad-scale land retirement into ngahere (native forest), covering important factors including: weed and pest control before planting, mix of forestry-grade coloniser species, planting density for various tree species, soil biome, and establishment timelines.
Benefits of the Tīmata Method
The Restoring Farmland into Ngahere project builds on a 10-year Primary Growth Partnership project that retired over 400ha of marginal land into manuka plantations for honey, then applied that knowledge to broader land retirement into mixed natives on steep erosion-prone slopes, riparian margins, and critical source areas.
Over that 10 years, several benefits of what has now been named the Tīmata Method emerged, including reduced costs, supply of trees and labour, and retention of ecological and economic benefits of establishing ngahere.
By using the Tīmata Method, landowners can significantly reduce the challenges associated with affordability and supply of trees and labour, while retaining the ecological end economic benefit of establishing ngahere.
The Tīmata Method also incorporates invasive plant and animal control, crucial for the project's success. By integrating weed and pest control before planting and making follow-up weed control dramatically cheaper in the long run, landowners can ensure the success of their reforestation project.
By using the Tīmata Method, landowners can significantly reduce the challenges associated with affordability and supply of trees and labour, while retaining the ecological end economic benefit of establishing ngahere.
Need for Greater Extension and Education
While the Tīmata Method has shown to be successful, for it to be applied to reforestation across Aotearoa New Zealand there is a need for greater extension and education to spread its benefits, says Dewes, and for additional resources and technical advice for pest and weed management.
Regional councils generally tend to stick with the up-front costs of conventional dense plantings, says Dewes, because this reduces ongoing expenses for pest and weed control. She advocates for more resources to be directed to support national reforestation aspirations. “We are going to need massive teams to do this,” she says.
Next Steps
The next step for the project is to develop additional educational resources such as an infographic, simply describing the Tīmata Method for landowners, agribusiness and forestry advisors, regional councils, and native forest restoration projects.
“We can increase the number of successful reforestation projects across Aotearoa New Zealand,” says Dewes. “The Tīmata Method can significantly reduce the cost of ngahere establishment on marginal and erosion-prone farmland – a need that is becoming more pressing every year.”
More information:
- Retiring Farmland into Ngahere report (February 2023)
- Restoring Farmland into Ngahere project
- You can also watch the video on YouTube
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8 Comments
Post cyclone Gabrielle, this seems to be most prudent approach to land management in erosion-prone areas of the Hawke’s Bay and Tairawhiti. Does the ETS make this economically attractive for landowners?
This is covered the “Economics and Funding” section in the supporting white paper. In many cases the class of land requiring reforestation into ngahere is contributing little if anything to the pastoral farming business. There are numerous examples in NZ where farm effective grassed area has been reduced and TOTAL pastoral profit from the farm (excluding carbon) has increased ETS carbon income assists the economics of land use change however the upfront funding costs for even the Tīmata method remain a challenge which will require government and banking support to assist the transition.
Have you looked at a trial run where kikuyu is dominant grass species?
I am unaware of no specific trials as such. At Pukekauri Farm we have successfully applied the Tīmata method on kikuyu pasture – refer to photos of six year planting in the white paper. Establishment whilst still significantly cheaper, requires much more diligence to maintain release of plants. In our case we did around 3 hand releases which was sufficient. Higher grade plants are also recommended in this situation but planted no closer than 2m.
In Christchurch Port Hill ranger Di Carter has been using a similiar method for 15 years to reforest the Port Hills. She grazes sheep ( who avoid kanuka) to supress grass till canopy closure. What is the latest research re root fungi establishment on planted kanuka? Do the beneficial native fungi infect planted kanuka? Is there any downsies during thd life of the kanuka if exotic nursery fungi take over the roots?
It is possible to graze under the Manuka and Kanuka for a period until near canopy closure however other bird attracting species will likely be wiped out if they are included in the planting mix. Some landowners graze sheep on their 100% planted Manuka honey stands. Others use the Manuka/Kanuka to shelter ewes and lambs during southerly storms. The high proportion of Manuka/Kanuka in the planting mix reduces browsing damage from pests.
Manuka and Kanuka are described as a nursery crop because they play a key role in the introduction of friendly fungi which allows other native species to thrive. This point is covered in the Technical Report “Soil Biome – the important role of Mycorrhizae”
Is anyone aware of this method being used in the Southland region?
This happens naturally. Manuka grows so dense and dark it suppresses most weeds. After the kanuka comes up through it the forest becomes more open and broadleaf plants like karamu attract birds, bringing many more seeds which germinate and develop because they now have enough light. This has been observed closely over about 100m x 10m on the SouthEastern margin of Eskdale Forest in North Shore, Auckland. The North Shore City Council stopped mowing this part of a recreational grassed area surrounded by regen kauri forest in, I estimate from googleearth history, about 2000, to enlarge the forested area. I do not believe there has been any planting of this 100mx10m, or herbicide use at least in the last decade or so, so the succession is fascinating and very beautiful, including the spread of native mosses which retain moisture and nurse the podocarp seedlings. Handweeding has taken care of most of the invasives, both old established and annual birdborne, since 2018. Wilding pines have been allowed to grow unfortunately, but regen is occurring under them too.