It probably won’t be news to many people that New Zealand farms are disappearing at an alarming rate and being replaced with pine trees (Pinus radiata). Given the poor returns on sheep and beef farming combined with the incentives provided by the Emissions Trading Scheme, it makes financial sense for many farmers to either sell their land to forestry or cover it with these fast-growing cash crops and claim carbon credits.
At Mangarara – the 600-hectare farm in the Hawke’s Bay I run with my wife Rachel – we believe that relying on pine as a solution to our economic woes is not the answer, and could in fact cause more harm than good in the long term.
For the last few years, we’ve been experimenting with ways we can take advantage of the ETS while maintaining our core business of farming and increasing plant biodiversity at the same time.
Our tree planting journey began in 2008, when I contacted Air New Zealand to explore the idea of creating a programme where their customers could use Airpoints to purchase trees for planting on the farm. I was put in touch with their environment manager, and we ended up becoming the inaugural project for the Air New Zealand Environment Trust. We received three years of support to plant 85,000 trees all over the farm, the majority of them native species planted on 20 hectares of steep, erosion prone hills.
Since then, our journey has led to more partnerships with organisations that have allowed us to continue native planting across our farm, much of it on land that’s unsuitable for grazing.
The issue, however, is that planting natives doesn’t make a lot of financial sense. They are more expensive to plant, and their slower growth means pine trees sequester carbon more quickly in the short term while earning far more carbon credits.
But because we didn’t want to plant more pine trees, we started to look at other exotic species – ones that would integrate with our grazing system while also generating income. That’s what led us to silvopasture.
Our silvopasture system
The core of our farming business is finishing beef cattle. We run about 100 Angus beef cows, finishing beef heifers, and a mob of dairy heifer grazers – around 750 cattle in total plus a mob of 600 finishing lambs.
I did a permaculture design course years ago and one of the key principles I learnt was designing systems to have multiple benefits. Silvopasture is a working example of this idea. It involves planting specific tree species within a pasture system with the goal of providing multiple benefits for the grazing animals, the soil, and the farmer.
For example, certain tree species – such as poplar (Populus) – provide shade and shelter, mulch for the soil in the form of dropped leaves, carbon credits through their fast growth, and eventually timber through the sawmill we have on the farm. The prunings provide an excellent supplementary feed for the cattle as they graze between the rows. They absolutely love this and we call it “cow candy”. It provides minerals they don’t get from the pasture and adds diversity to their diet. Offcuts from the trees can be chipped for mulch, compost, or biochar production.
We also use trees such as willows, maples, liquidambar, ash, flax, karamū, tagasaste, and fodder willows – each species offering its own unique range
of benefits.
In our system, the trees are planted in rows 20 metres apart throughout our pasture. Within the rows, each deciduous tree (poplar, willow, maple, and liquidambar) is planted six metres apart, with support trees (flax, karamū, tagasaste, fodder willows or fruit and nut trees) planted in between. The rows are planted north to south, allowing sunlight to reach in between them and promote grass growth throughout the year.
A key feature of this system is that it allows us to control the holistic grazing of our animals. Each row is protected from the cattle by a single-wire electric fence on either side, enveloping a two-metre space where the trees grow. The cattle are confined to a break in between the rows and are shifted twice a day. This allows us to optimise our stock density, prevent overgrazing and give the grass time to recover, a key practice to encourage healthy soil.
Water is provided to the cattle through mobile troughs, which we shift into new breaks when we move them.
Using the ETS
For a forest system to qualify for the ETS and earn carbon credits, it must meet certain criteria. For example, tree canopy must cover – or have the potential to cover – at least 30% of each hectare of land that is being registered under the scheme.
Additionally, the space between the driplines of the trees must not exceed 15 metres. Our rows were planted 20 metres apart to preserve as much grass as possible for grazing, However, when the trees mature and their crowns fill out, the space between the rows will reduce to less than 15 metres, meeting the criteria.
While our rows have a variety of tree species, the majority are poplars. As a result, the entire forest is categorised as “exotic hardwood” which sequesters a specific volume of carbon based on its age, according to MPI’s look-up table. We can’t claim any credits on the fruit and nut trees growing between the rows.
To prove that our forest is as we say it is, we have to submit evidence to the Ministry for Primary Industries when we register under the ETS. The main form of this evidence is through farm maps prepared according to the Geospatial Mapping Information Standard 2023.
To do this yourself, you need to know how to create shapefiles (a digital mapping file format). If you’re unfamiliar with the process, it’s best to hire an expert or forestry company to do this for you, as we did.
Because the total size of our ETS forests are relatively small, we don’t need to have someone from MPI visit and assess our land. However, if your forests are over 100 hectares in size, then an MPI approved consultant will need to carry out an on-site assessment.
How We Make Money
From a financial perspective, we are already seeing a return on our silvopasture system. Factoring in the electric wire and water infrastructure, it cost about $1,000 per hectare to plant the trees. With carbon worth $56 a tonne at the time of writing and our five-year-old forest sequestering about 29 tonnes of carbon per hectare, we are already earning about $1,600 per hectare per year – a far greater return than from our sheep and beef farming.
It’s important to note that the rules around this are evolving, and it’s likely that the way I can claim credits on my trees will change over time.
But ultimately, it’s not about the money. Even if there’s zero value placed on carbon, silvopasture is still a really good farming practice. We’re creating habitat and biodiversity. We’re creating shade, shelter, fodder, timber and nutrient cycling all while sequestering carbon from the atmosphere. Most importantly, we’re demonstrating a viable alternative to vast swathes of pine trees.
The new ETS laws specify that farmers can’t plant more than 25% of their LUC (Land Use Capability) class 1-6 farmland in exotic forestry for the purpose of ETS registration. This is to slow the already excessive conversion of food production land to pine forests. Although it’s well-intentioned, it does put limitations on the potential of mixed species silvopasture systems and the best of both worlds that it brings.
Not long ago, fellow regenerative farmer Sam Lang – who helped design my system – and I looked at the potential carbon sequestration value of exotic silvopasture systems if planted across New Zealand. We worked out that if most of the country’s pastoral land was planted with 75 exotic softwood trees per hectare, it could offset 100% of NZ’s carbon emissions.
And we wouldn’t need to plant a single pine tree. ■