Farm Forestry New Zealand

The billion trees programme - Here’s how

Ian Cairns, New Zealand Tree Grower May 2018.

An open letter to Minister Shane Jones.

The government’s billion trees programme will provide opportunities for foresters. With the conservation estate, Landcorp and Māori land, initiatives are already under way. It is less clear what the initiative might mean for managers and owners of freehold rural land.

New Zealand has 14 million hectares of grassland and two million hectares of planted forest. Farm and forest businesses typically include a component of marginal land, also known as hill country, with significant erosion risks if maintained in pasture and which does not contribute significantly to farm and forest output. A 2008 Ministry for the Environment land use report estimates marginal land at around a million hectares.

It is this land which should be the prime target for afforestation under the billion trees programme. Under pastoral use it needs soil conservation measures. Under commercial forestry, it is either not planted in the first place, or if planted, may not be harvested. Stepping back, and bearing in mind a split between grassland, planted forest and marginal land, what does the tree planting budget look like?

Replanting commercial forestry replant

The one billion tree calculation will include replanting. So, if over the 10-year period, New Zealand harvests and replants 400,000 hectares, at a planting rate of 1,500 stems a hectare, then replanting might contribute 600 million to the target number. The contribution to the planting target would therefore be 600 million trees.

New commercial forestry

Where might commercial forestry establish today? MPI's own initiative gives the clue. It is asking for expressions of interest from land owners with 200 hectares or more of reasonable quality land. In other words, head-to-head competition with the farmers for land.

MPI is offering leases or joint ventures with the land owner retaining all carbon rights. The financial offer will be case-by-case, but I would pick that the incentive to convert will be pitched at the level of the Afforestation Grant Scheme of $1,200 a hectare. This is at a time when grazing properties suitable for conversion are selling for more than $11,000 a hectare.

While pastoral land values are so high, I predict the government inducement will not tip the land use balance. The market timing is simply wrong. The land likely to be converted over the 10-year period if 100 farms are involved would be 20,000 hectares. With an indicative tree stocking rate 1,500 stems a hectare, the contribution to the planting target would be 30 million trees.

Marginal land

Most hill country sheep and beef farms, and planted forests have small areas which, for reasons of slope, aspect and erosion potential contribute little to the core business. Carter Holt Harvey estimate these areas account for 15 per cent of their forests. Beef and Lamb NZ give an effective average area of 766 hectares for North Island hard hill country farms. Perhaps on that average farm there will be 30 hectares of ineffective land. How might such marginal lands be better used?

Some, but not all of this land, is suitable for growing trees. For the purposes of discussion, I estimate the land resource potentially available at 500,000 hectares. Management options for this land include −

• Doing nothing
• Planting or replanting in radiata or other commercial species hoping that improved harvesting technology will make for a profitable harvest in 30 years
• Planting willows and poplar poles, debris dams and continued grazing which needs new public money
• Managed reversion to permanent native forest which will need grants.

Doing nothing

Doing nothing is not really acceptable to farmers themselves, and even less so to the general public. Nevertheless, experience shows that half of farmers will simply not get around to taking up the opportunity. Land in this category is around 250,000 hectares and the contribution to the planting target would be zero.

Plant or replanting in commercial species

Bearing in mind that the main limitation to profitable harvesting is road distance and access, there is a variety of new harvesting technology that may reduce harvesting costs. Against this, returns may still be low due to poor tree form and slow growth rates. If the land is planted and just abandoned, this is also problematic in that crop trees may topple when they become mature.

Land in this category is around 100,000 hectares. The contribution to the target would be 150 million trees.

Willows and poplar poles

Planting poplar and willow poles is a proven strategy on pastoral farms and the species used are non-invasive. There is limited technical capacity in regional councils, but it could be rebuilt over the 10-year period. The cost per tree is high, but the cost per hectare is low. I argue for a funding boost.

Land in this category is around 50,000 hectares and the tree planting rate 40 stems a hectare. The contribution to planting target would be two million trees.

Managed reversion to native forest

Uptake for managed reversion will depend on the level of incentive payment. A number of farm foresters I have spoken to who have recently harvested and are facing the what-now decision lean towards native forest.

In addition to the soil conservation benefit, case studies show a marked increase in local bird life as forest processes begin again and there is the corridor effect from the mountains to the sea. A diverse tree and shrub environment is far more resilient to climate and disease.

It would be prudent for any government support to be in the form of a post-establishment grant rather than a subsidy to tree nurseries or a payment to the land owner for every tree planted. There is a high risk of establishment failure.

Land in this category is around 100,000 hectares with a tree planting rate of 2,500 stems a hectare. The contribution to the target would be 250 million trees.

If we add all the figures together − 30 million, 600 million, 150 million, 250 million and two million − it gives us a grand total of just over a billion trees. The target can be met.

Conclusion

The above analysis is unashamedly broad brush.

Nevertheless, it shows that −

• The target of a billion trees is certainly attainable if the net is cast wide enough
• On private land, the big opportunity is planting small areas of marginal land rather than whole-farm conversion to commercial forest.

Incentives

The key to land owner response is the level of incentive. I believe that middle-class New Zealand, who pay most of the nation's tax bill are receptive to an increased level of government activity in the economy particularly for environmental and conservation purposes. Allow me to join the bidding. For commercial forest the level of support will be hidden in the terms of the lease or joint venture arrangement. Depending on discount rate assumptions, it could be around $1,200 a hectare.

How should soil conservation planting be treated? If 40 stems a hectare of poplars produce a similar soil conservation benefit as 1,500 stems a hectare of radiata pine, and that is worthy of a $1,200 a hectare grant, the payment from central government to support regional council planting programmes should be $30 a poplar pole.

For managed reversion you might expect large site-by-site variation. On a grassland site, the traditional prescription has been to start with 10,000 stems a hectare. Where scrub has already begun to establish, it may be that no planting is required just a fence, along with intensive weed and pest control. This is not cheap, but neither is a nursery-raised tree.

An experienced consultant forester comments that to date the sector has been very unsophisticated in its approach to the establishment and management of native forest. Five years of operational research points to new methods with much lower levels of initial stocking. The cost of this kind of afforestation is unavoidably high per hectare, but then so is the public benefit

I propose applicants be required to submit a 10-year plan and indicative budget to the proposed new Ministry of Forestry who will screen for feasibility. The grant offer would be scaled according to Cabinet-agreed criteria to a maximum of $8,000 a hectare be paid after 10 years if establishment has been successful.

Final points

The expression of national targets in terms of trees planted is novel to foresters who are accustomed to hectares harvested, replanted or newly planted. There is scope for political mathematics. For example, if a commercial forest is planted at 1,500 stems a hectare and the final stocking after thinning is 350 stems a hectare, perhaps the latter figure is how the contribution to the national target should be counted.

Similarly, with managed reversion, a grassland site might be planted at 2,500 stems a hectare. In 10 years tree numbers might have risen to 3,500. Which figure do you use? Should an auditor try to distinguish a tree planted by a human from one that was planted by a bird? In both cases, what really counts is the area of forest established.

For general public, such questions are a little technical. The one billion trees target inspires. What matters to the land manager is the level of financial assistance. The calculation of progress against the target can be left to the Ministries concerned.

Ian Cairns is a Hawke's Bay forester and was formerly a Senior Policy Analyst with the Ministry for the Environment.