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The New Zealand Redwood Industry

Taumarunui Redwood Stand
Taumarunui Redwood Stand

NZRC President Dan Kruger in the 90 year old redwood stand at Taumarunui

July 2013, Simon Rapley, General Manager – New Zealand Redwood Company

New Zealand Redwood Company recently carried out a survey of NZ forestry nurseries to determine the area of redwood forest established in NZ in recent years. The nurseries provided sales figures going back to 2001 for both redwood seedlings and clonal redwoods.

We also asked the nurseries if they knew the stocking rates (the number of trees in a given area or the tree spacing) used by their customers. The numbers were surprising.

The most commonly used stocking for New Zealand pine and fir seedlings is 800 stems per hectare (SPH), or in US terms, 325 stems per acre (SPA).

In this scenario, growers plant double the number to be harvested, and then thin the stands down to approximately 400 SPH (162 SPA) while the crop is still young.

This pre-commercial thinning, also known as “thinning to waste”, allows the grower to pick the best trees. The trees that are culled are too small to be of any value, so they are left on-site.

In contrast, redwood needs very little if any pre-commercial thinning, so the most commonly used stocking rate for redwood propagated from cuttings is 500 SPH or 200 SPA.

Redwood Plantings By YearFrom this information, we can estimate the area of redwood forest by stock type and by age. This is depicted in the chart . Most of these forests are established on productive sites and are expect to yield 1,000 cubic metres per hectare (80 to 90 MBF/acre) of wood at age 35. This rivals even the best stocked stands in California.

Reproducing any plant from cuttings is known as vegetative or clonal propagation. If you’ve ever taken a cutting of a plant and rooted it, you’ve done clonal propagation. The majority of common houseplants, garden ornamentals, crop plants, and fruit trees are reproduced in this way. Clonal propagation is how NZRC reproduces redwood.

North Island Redwood Locations

Taumarunui is centrally located in the redwood working circle.

Just to be clear, clonal propagation is not the same as a Genetically Modified Organism (GMO), a process which involves mutation, insertion, or deletion of genes. NZRC does not propagate GMOs.

Plantings of redwood began to increase in 2002 with the introduction of clonal redwood forestry by NZRC. The establishment spurred an interest in redwood forestry, especially with the use of clonal stock. This can be seen in the chart.

Virtually all NZ redwood forests are being pruned to decrease defects and increase quality. Pruned logs will yield more valuable lumber grades such as Clear Heart, Clear, B Heart, B, Construction Heart, and Construction Common.

Okota Forest (NZRC) 720 hectares 1800 Acres Ages 1 to 10
Aria 950 hectares 2,350 Acres Ages 5 to 6
Otorohanga 500 hectares 1,240 Acres Ages 2 to 4
Whangamomona 1,200 hectares 3,000 Acres Age 1 (balance yet to be planted)

From this information, we know that there will be more than enough redwood harvested in the future to supply at least one specialist redwood sawmill, and probably more.

Stand of 90-year-old redwoods outside of Taumarunui

This stand of 90-year-old redwoods outside of Taumarunui is perhaps the most productive in the world.

Even if the current trend of increasing log exports continues, it is still likely that the higher-value pruned logs will be sawn in NZ.

The geographic centre of the redwood working circle is Taumarunui. Given that Taumarunui has a population of 5,000, existing sawmills, and the main trunk line of the North Island Railway runs through it, Taumarunui is the most likely location for a future sawmill cutting redwood.

Not surprisingly, Taumarunui is also known among foresters as having the best combination of soils and climate for forestry. Radiata pine production is not only very high around Tamarunui, but the quality of the wood is amongst the best in New Zealand.

Taumarunui is the location of probably the most productive redwood stand anywhere in the world. At age 90, the redwood stand boasts 3,500 cubic metres of wood per hectare (340 MBF per acre). This kind of redwood volume is unheard of anywhere else.

North Island Railway Map

The North Island Railway runs through Taumarunui, giving a good option for future transport of redwood.

There are valid reasons to plan future redwood forests within economic transport distance of Taumarunui. Most other north-island redwood forests are within a two-hour haul to Taumarunui, with the option of rail transport which may be preferable in future.

NZRC continues to be the number one source of redwood planting stock in New Zealand, and manages a continuously growing area of redwood timber.

The redwood industry in New Zealand is growing, and is well on the way to delivering a sustainable, high value, high quality forestry crop in the not-so-distant future.

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