Sequoia sempervirens – coastal or Californian redwood – is usually simply known as ‘redwood’ to New Zealand growers. The species originates in a narrow coastal strip running from northern California to southern Oregon.
The area of redwood in New Zealand is estimated to be around 10,000 hectares (2018), and has steadily increased over the past decade.
‘Giant’, ‘Inland’ or ‘Sierra’ redwood (Sequoiadendron giganteum) is also grown throughout New Zealand but rarely at commercial scale.
Information resources for growers
The best sources of practical information for redwood growers in New Zealand are:
- NZFFA Redwoods Handbook – the most comprehensive source of information available for growers. Part of the NZFFA Best Practice with Farm Forestry Timber Species e-handbook series.
- NZFFA website redwoods section – a selection of information including Tree Grower articles and grower videos.
- Redwoods section of the NZ Wood website – good information on properties and utilisation.
- The New Zealand Redwood Company website – the NZRC is New Zealand’s largest single grower of redwoods and also promotes the species and supports other NZ growers.
- The redwoods: FRI Bulletin 124, Pt 13, Introduced forest trees in NZ – Recognition, role and seed source. NZ Forest Research Institute 1994. More detailed description of Sequoia sempervirens, Sequoiadendron giganteum and related ornamental species, from seed source to processing and timber properties.
Current redwoods research
Redwoods are not currently part of an industry-funded research programme. However, the NZFFA Sequoia Action Group (SAG) and Scion have undertaken several small research projects over recent years. These are reported by Scion, in NZFFA SAG newsletters, and the NZ Tree Grower. Examples include:
- Genetic x environment analysis of growth and wood properties of the various clones and provenances on five Kuser trial sites. The Kuser trial is a network of sites across New Zealand where the same genetic material was planted at the same time. (MPI SFF Project 404886)
- Heartwood durability study, which developed a new method for assessing redwood durability. The study concluded that young NZ-grown redwood has similar heartwood durability to second rotation Californian-grown redwood (MPI SFF Project 408110).
The following research priorities have been identified by the NZFFA SAG:
- Update redwood growth models with new data
- Analyse effects of final crop stocking to inform fundamental redwood forest management
- Assess redwood nutrition to inform forest management
- Review harvest mechanisation for redwood literature
- Characterise interactions between mycorrhizae and fungicide on redwood seedlings in the nursery.
Redwoods have a wide range in New Zealand, and can be found growing well on selected sites throughout the country.
In general, redwoods:
- are a versatile species, but produce their best timber on sheltered, inland sites
- perform best in well-drained, fertile soils, with regular rainfall. Frosty and water-logged sites are best avoided
- grow relatively slowly at first, meaning good weed control around young trees is more important than for other species
- have good potential for both carbon accumulation and erosion control because they are long-lived and coppice from cut stumps
- produce light, moderately durable timber with a range of indoor and outdoor end uses including weatherboards, decking, outdoor furniture and indoor joinery
- are thought to have very good market potential in the USA, where supply is now limited.