Manuka with an impressive show of flowers late November.

Tree planting ‘just what I do’

A passion for planting trees on the family farm has evolved to include manuka and other honey species for a Marlborough farmer. Joanna Grigg reports.

David Dillon planted his first tree in his school holidays aged 10. From then on tree-planting has become an ingrained annual event on the farm; like shearing or lambing, and it’s reaping benefits.

The 1500 hectares of the Marlborough hill country property The Throne, are treated as an extension of the homestead garden. David and Sue Dillon select areas and tree species to plant each year; driven by aesthetics as much as the need for woodlot income, nectar, shade and shelter for stock.

The results are stunning. Sweeps of shelter belts frame pastoral views. After the drive up the Waihopai, through a vineyard monoculture, it is an oasis of leafy green.

“After travelling to Europe in 1968 I felt New Zealand farmland seemed naked and bare in comparison,” David says.

Pinus radiata woodlots totalling 40ha are farmed in rotation, on areas close to existing farm tracks. The pines are in the Emissions Trading Scheme and are replanted to avoid carbon liabilities.

“For profit you grow Pinus radiata as the Chinese are familiar with it and it’s fast; it’s the sauvignon blanc of the forestry industry.”

‘My advice to farmers entering a relationship with a bee company is to ensure they have good ethics and want to work long-term.’

In 2010, Paul Millen, forestry consultant, encouraged the Dillons to trial seven different eucalypts for naturally produced durable hardwood posts, as part of the NZ Dryland Forestry Initiative. Plantings now cover 10ha of a very cold hard ridge, with the most successful varieties being cultivated for commercial blocks. A favourite is E. niten as it is a fast-growing tree, although they are quite site-specific, Dillon says. This winter more eucalypts have gone into a flat roadside paddock.

David Dillon with recently planted manuka.

David was chair of the Marlborough Tree Growers Association and is supportive of forestry trials. They are happy to look long term when investing in woodlots. A 7ha westerly face, has been planted in the oak Quercus Robur for a woodland feature and timber for the next generation.

The farm has a forested gully holding a large and important population of the endangered Marlborough endemic tree, northern pink broom, which has been fenced to exclude stock. The Throne has five other Significant Natural Areas (SNA), including a significant flax wetland. With assistance from the Marlborough SNA Project, it has been fenced, cleared out of most weeds and planted in 2000 native trees. This includes 500 kahikatea (white pine), totara and cabbage trees.

In 2017, 300 lime trees (Tilia platyphllos) were planted for nectar for bees. Other favoured species include Cupressus leylandii, Tasmanian blackwoods and Alders in a mixed-species shelter belt and Eucalyptus oblique (Australian oak) at the edge of pine forests.

More than 4000 magpies have been trapped, as native birds are highly valued.

“I love song birds but like to keep magpie numbers down.”

In 2016 a 10ha manuka stand was planted on a very hard, dry, north face, at 800 stems/ha, which is considered a lighter stocking rate. Manuka was choosen because they knew it would suit the dry site, provide erosion control and add a nectar source for bees. The resulting honey is likely to be multi-floral, sourced from a combination of sources flowering at the same time, including white clover.

Farmers interested in a higher-value manuka crop should avoid planting a new site near a large source of non-manuka nectar. Planting rates can be up to 2500 stems/ha for more gentle contoured land.

For a weed-infested former pine block, it may need two blanket weed sprays over a nine to 12-month period, before planting into manuka. The Dillon block only needed spot spraying for grass control.

The Afforestation Grant Scheme was used to help pay the costs of establishing the Dillon block. The first 10 years of carbon sequestration credits are claimed by the government. This 31 tonnes/ha is worth about $744/ha. A hectare of indigenous forest over 35 years is expected to sequester carbon stock of around 286 tonnes, Pinus radiata 825t (Marlborough/Nelson) and exotic hardwoods 729t/ha (Post-1989 Look-Up Tables, 2015). Manuka lifespan is only 30 to 60 years. Options to increase longevity of manuka is to trim it (and use the trimmings for oil). This keeps it in a juvenile state.

The Dillons’ daughter, Hannah, has organised for a local beekeeper to access the farm for an annual rental.

“We made a new relationship with a local beekeeper, who is a lot more transparent with payments than our previous arrangement.

“My advice to farmers entering a relationship with a bee company is to ensure they have good ethics and want to work long-term.”

Many trees are at the height where fences can be removed and grazed around by cattle and sheep. With the younger generation on the farm, David relies on son Tom to run the sheep and cattle side of things, freeing him up for tree maintenance. He spends time every day on tree work.

“It makes my day so enjoyable.

“When you have drought and bad prices, you will always see your trees growing each year which brings huge satisfaction.”

Government tree planting campaigns could learn a lot from The Throne. Trees are not planted as a monoculture, the species range is varied and harvesting is staged with short, medium to long-term maturing trees. Trees are planted for shade and shelter, erosion control, aesthetics, biodiversity, bird song, improving water quality, nectar for honey and wood returns, not solely to sequester carbon – if at all.

Trees help screen the motocross track and contain dust. Stock welfare has been improved with the integration of woodlots and grazing. Business opportunities now exist, with the next generation exploring tourism options, that take advantage of the setting.

“We are looking at health-based retreat options; obviously quite an investment,” Hannah says.

“Potential of the area is huge, it’s very exciting.

“Ambience is becoming more valued and we are very fortunate to have it here.”

A second manuka planting sits around Hannah’s picturesque yoga shed, sited on a plateau edge. While mainly for aesthetics, the 1000 UMF five manuka saplings will also be used for honey production. They were also planted with crystals to hold moisture but polythene was laid around the trees to reduce grass competition and is working well. David Dillon also rates pea straw as an excellent mulch, as it lasts such a long time.

About manuka

  • Grows from lowland to 1800m
  • North-facing, warm site best
  • Selective breeding underway e.g. for plants high in dihydroxyacetone (DHA) levels in the nectar. This contributes to favoured high Methyl Glyoxl (MGO) in honey.
  • For mono-floral honey, a large north or east-facing plantation site, with warm weather over flowering is best. Under 50ha is considered a small plantation and runs the risk of dilution from other more favoured-by-bees nectar sources. Isolated plantings is best to restrict bees.
  • Typically three metres tall at four years old.
  • Has a life span of 30 to 60 years and is often overtaken by other native forest species, as seedlings don’t like shade. Trimming will keep manuka in juvenile stage.
  • Manuka supports a wide range of biodiversity.

For more, see The Manuka and Kanuka Plantation Guide, April 2017, NZ.