Northland Forestry Nursery

August 2012

Kevin Strawbridge is producing seven million pine tree seedlings at his nursery per year

Northland Forestry Nursery began in 2004 and has recently expanded via leased land to 16ha planted area, on which seven million pinus radiata seedlings are grown annually. NFN has expanded to supply 70% of the Northland region’s seedling needs because its success rate measured in seeds planted to trees harvested is over 95%, against the industry standard of 85%.

Kevin Strawbridge worked for 20 years for Carter Holt Harvey as a forest manager and marketing manager before moving to Kaikohe and managing a forestry nursery. With Christine he purchased land in Kerikeri in 2001 and started a nursery of his own, then in 2004 after a search for suitable land they bought 19ha in Kaikohe. Recently a lease on an adjoining piece of land has enabled expansion of the planted area to 16ha. The first year’s harvest at Kaikohe was 1.2 million seedlings in 2005. Kevin is still very much hands-on in the business, employing two permanent staff members and a larger short-term crew during harvest.

Kevin Strawbridge founded the Northland Forestry Nursery in the early 2000s, using his extensive knowledge of the industry and his exemplary customer relations. NFN is now a major nursery, one of 14 nationally. A majority of NFN seedlings are grown on contract to Northland forest management companies, although some seedlings go out of the province. In some cases the customers supply the seed and have it grown to order. Pine seeds are planted in September and the seedlings harvested from May to August. This year over seven million seedlings will be wrenched, lifted, and then boxed with exact tallies for dispatch to customers at the times they specify.

NFN uses a Polaris ATV to replace tractor work and reduce compaction. Kevin has modified a precision drill for his soil conditions.

Soil management is very important, with regular soil and foliage testing, include organic content, to maintain the optimum conditions for what is a monocultural annual crop. Cut tops and roots are left in the ground after harvest. As the newly leased land comes into production, Kevin is considering a rotation with spelled areas growing a green feed crop to boost soil organic matter. Care is taken to establish and maintain the correct mycorhiza (fungi) in the soil, which is a very important part of seedling vigour.

As the nursery contains a lot of bare land and friable soils, sediment traps have been installed to cope with water run-off after heavy rainfall.

Kevin uses a resin-coated slow release fertiliser and nitrogen sparingly, while irrigation is also used only when necessary.

A sound understanding of animal and weed pests has been gained over many years. Different products have been trialled to achieve the best results for this business. Careful monitoring and the use of low spray rates on a regular basis controls infestations while still at low levels.

Given that damage to trees can quickly place seedlings outside of specification criteria, weed and pest control is usually preventative. However close monitoring means that spraying only takes place when needed, and the chemical residues are also closely watched.

NFN employs casual staff members from the Kaikohe area during harvest time – May to August. These are trained to a high standard to ensure the seedlings are harvested, trimmed and boxed, delivered to customers and achieve the 95% quality assurance record when replanted in forest sites.

Kevin has heard back from one major client, which took 900,000 seedlings last year, that the survival rate of young tree establishment was actually 99.7%, after allowing for those planted in non-viable locations.


From late April onwards this year, NFN has been topping, undercutting, root trimming, wrenching and lifting seedlings, with appropriate times between these operations to encourage the growth of tops and roots.

Topping is done initially to 35cm, to encourage regrowth.

Undercutting is done with a reciprocating bar to leave a 7-10cm tap foot length.

Lateral root pruning uses a pair of disks towed behind the tractor but steered by an operator sitting on the implement.

Wrenching is done about three weeks after undercutting, and again afterwards. It lifts the whole earth mass and pops the seedlings out of the ground, to encourage then to grow more fine roots.

Weather conditions dictate the timing of these operations, and Kevin keeps in contact with the customers as optimum replanting times approach.

Final harvest is done with a fixed lifting bar behind the tractor, followed by skilled lifters who select rejects and trim the roots of handfuls of seedlings, and count into plastic boxes containing 100 plants, weighing around 10kg. All soil is shaken off roots and the final height is about 40-45cm (30cm green top, 7-10cm of root depth and an intermediate zone. Boxes of seedlings can be misted and chilled down if they are to be kept at NFN over the weekend before dispatch. On average truckloads of 30,000 seedlings at a time (three tonnes) are sent to forestry companies and their planting contractors. That’s well over 200 truckloads a year. But consignments of up to 100,000 trees can be dispatched at one time.