Diversified Species

Introduction

The Diversified Species Research Theme focuses on plantation forest species other than Radiata Pine that are or have the potential to be grown successfully on a commercial scale.  Separate working groups oversee research programmes on Eucalypt species, Douglas fir, Californian Redwoods, Cypress species and Indigenous species

Currently New Zealand imports 62,900 M3 of timber valued at $63 million. Much of this is durable decking and decorative timbers from unsustainable tropical rain forests. In addition, large quantities are also imported as finished-product furniture. There is the potential to replace much of this with sustainable plantation wood from a variety of species proven in New Zealand as alternative speciality use timbers.   Historically, New Zealand's native tree species provided most of the domestic supply of high quality decorative timber, but the harvestable resource is now very small and has been further reduced by legislation.

Diversified species provide wood for specialist purposes not met by Radiata Pine and they can also be alternatives for Radiata Pine on colder high altitude sites prone to winter snow damage (eg Douglas Fir) and on higher value land where traditional radiata pine management is not competitive with other land uses (eg Cypress species).  Other species also have potential in carbon farming ventures as they have the potential to grow faster (eg Eucalypts) and longer than radiata pine (eg Redwoods and Douglas fir). Native species are slower growing but kauri, beech, and some of the podocarp species have potential to be managed for long term sustainable production of wood in conjunction with other forest values.

Research work in each of the species groups includes genetics, silviculture, nutrition and investigation of wood properties and their relationship to product development.

Long-term trials to monitor growth and the effects of genetics, management and environmental factors on yield and quality are key components of the alternative species programmes.

A key output of this research will be a Decision Support System to match species to sites for new forests or replanting.

Information on seed sources, propagation and use options will help foresters to choose from a range of potential species likely to meet commercial forestry objectives in their region.

It is these research programmes that provide the knowledge and tools which give forest owners the confidence to invest in these other species.

Eucalypts

Eucalypts are currently grown commercially in New Zealand for chip, pulp and sawlog production. The multitude of Eucalyptus species and hybrids means New Zealand has an abundant smorgasbord to choose from to match sites and end use.  Good establishment practices, continual genetic improvement and careful management of eucalypt stands are critical for good growth and the production of high yields.

Eucalypts have the potential to replace much of the speciality decorative timbers currently imported in to New Zealand, much of it from unsustainable tropical rainforest origins.

Douglas Fir

In New Zealand, Douglas-fir is the second most planted forestry species after radiata pine. Its timber is widely accepted on the world market, and it has a good reputation for structural use. With around 112,000 ha of Douglas-fir plantations, NZ is the third largest grower after France and Germany, outside of the Pacific Northwest.

Douglas-fir grows best in the South Island, on colder, snow-prone sites. On the more mild sites around the country it usually takes second place to radiata pine. Annual new planting since 1995 has varied between 1,000ha and 9,000ha. Most of this is confined to the eastern and southern foothills of the Southern Alps, at altitudes of 350m to 950m above sea level.

Californian Redwood

Californian coast redwood (Sequoia sempervirens) originates from the Pacific coast of the United States where the timber was sought after for a wide range of uses. Timber originating from “old crop” forests had a reputation for stability and high natural durability of the heartwood. Almost all remaining old growth forests are now protected in reserves and the vast majority of the present harvest is from second and third growth stands that produce timber of inferior quality. Despite the reduction in timber quality, particularly heartwood durability, demand remains strong, exceeding the capacity of the natural resource to supply, to the extent that price resistance is the limiting factor for upper grades.
This vacuum of supply gives an opportunity for New Zealand to grow plantation redwood to supply this readymade market, especially the higher quality clear grades from pruned stands, as these grades are no longer produced in reliable quantities from second growth forests. Several recent exports of sawn timber from New Zealand stands has demonstrated the acceptability of plantation grown material on the Californian market.

In addition to demand from the western sea-board of the USA, there is a market in South-East Asian countries that were traditional importers of the timber last century.

The utilisation pattern of Coast Redwood in northern California parallels that of Western Red Cedar in more northern States and Canada, indicating the potential for replacement of imported Western Red Cedar with locally grown Redwood timber.

There have been limited plantings of Coast Redwood in New Zealand for many years, but few stands have been well managed. Nevertheless these stands provide sufficient data to indicate that Coast Redwood is capable of achieving higher growth rates on a wider range of sites than has generally been indicated in past literature. Coast redwood is intolerant of heavy out of season frosts and strong prevailing winds, but achieves good growth rates on a wide range of soils of moderate to high fertility, in milder climates and where soil moisture is not limiting.

The re-coppicing ability of redwood is well known and this coupled with its shade tolerance indicates that it would provide a valuable role if managed sustainably on steep erodible hill country. Juvenile recoppice provides the opportunity for clonal propagation from trees selected for superior growth, form and wood qualities.

Cypress Species

The cypresses (approx 25 species) are conifers belonging to the closely allied genera, Cupressus and Chamaecyparis; members of the family Cupressaceae.  Cypress species have been planted throughout NZ for over 150 years.  They are characteristically mid to large sized trees with very desirable wood properties.   Cypress timbers currently make up the third most commonly utilised exotic timber species in New Zealand with approximately 20 000 m3 cut annually with most of this being cut from shelterbelts.  Good quality cypress wood is suitable for a very wide range of end uses including: high quality clearwood, decorative veneer, furniture, joinery, weather boards, sarking, mouldings, panelling, flooring, structural, decking and boat building etc.  The poorest quality timber is often used for garden sleepers and firewood. 

C. macrocarpa, C. lusitanica, Ch. lawsoniana

and the Leyland hybrids are the most widely planted cypresses in New Zealand. 

C. macrocarpa

originates from Monterey, California where its total natural distribution is about 30ha.  It arguably, has the smallest natural distribution of any of the world’s conifers and in California is regarded as a rare and endangered species. 

C. lusitanica

has a considerably larger natural range extending from 1200 to 3000m in altitude through central Mexico to Honduras.

Ch lawsoniana

origins are in southern Oregon and northern California at altitudes up to 1950m.  The Leylands are named clones, grown from rooted cuttings of inter-specific hybrids between a

C. macrocarpa

and

Ch. nootkatensis

or Alaskan cedar.