FAQs

Welcome to the NZ Wood Frequently Asked Questions

Pine

What alternatives are there to pine?

Commonly available alternatives to pine include Douglas-fir (Oregan pine), macrocarpa (Monterey cypress), Lusitanica (Mexican cypress) and Lawson cypress (Oregan cedar).

Information on alternatives to pine and their structural properties.

Information on Douglas-fir as an alternative solution

Visit the Species Index on the website.

How is NZ Pine graded?

Through good silvicultural management, New Zealand pine logs come in a range of qualities capable of yielding lumber grades to meet almost any requirement.

For detailed information about NZ Pine (Radiata Pine) quality and the conversion process go to Log Quality, Conversion and Grading page on the website.

Are there alternatives to H3.1 treated pine that comply with the building code?

Untreated macrocarpa, Lawson Cypress, Lusitanian Cypress or Larch are possible options.

To achieve an “acceptable solution” within an enclosed frame H3.1 treated radiata needs to be substituted with either:

  • Structural grade untreated larch, or
  • Untreated heartwood from the cypress species (or H1.2 treated sapwood). Macrocarpa is the most likely source, but Lawson cypress may be available although unlikely to be in large supply. (The heartwood is easy to identify, and available, if you find a supplier of the species.)

For both of these, because they are specialist species, they could be hard to source for structural purposes ie. MSG or VSG 8 or better. Very few producers will go through the “verification” steps for small scale volumes.

If MSG 6 is sufficient then visually graded “number one frame” will be an acceptable alternative. (Unverified “number one frame” is deemed MSG 6 and it can be used in place of MSG 8 but will require larger dimensions to give equivalent strength)

That leaves “alternative solutions”:

  • Research would support H1.2 boron treatment as being suitable for enclosed frames in any situation and some Building Consent Authorities (BCAs) will approve H1.2 Douglas-fir in place of H3.1 Radiata.

If it is an outdoors or exposed structural application eg. posts where 50-year durability is mandated, then the building standard NZS 3602 does not designate any commonly available untreated wood as an “acceptable solution”.

NZS 3602 allows untreated heartwood from redwood, western red cedar, cypress species and New Zealand beech for outdoor use in stairs, decking, handrails where a 15-year durability is required.

(Note: because of the risk of leaching, H1.2 boron should not be used in exposed areas unless it is primed and three-coat painted.)

For more information on treated timber and building legislation visit the Treatment and Durability section of the website.

Look at the table of alternatives to pine and their structural properties.

Are there special timber treatment requirements for NZ Radiata timber in tropical conditions, especially insect attack?

Use CCA treated timber for termite protection, H2 is for framing timber, H3 (not H3.2) for above ground exterior and H4 or H5 for ground contact.

Australian standards are usually applied with regards to dealing with termites in the Pacific Islands.

AS 1604.1 for sawn and round timber, AS/NZS 1604.2 – AS/NZS 1604.5 for reconstituted wood products, plywood, LVL and glue laminated products.

These standards would meet or exceed likely requirements in tropical areas where termites are a hazard.

Standards New Zealand: Timber Treatment –

What are the benefits of kiln drying timber?

Timber is the name given to wood that has been prepared for the purpose of building or carpentry. Preparation includes the drying and sometimes treatment of this wood.

There are a few methods of drying wood in New Zealand including:

  • Ambient temperature drying – air drying and forced air drying.
  • Low temperature dryers (up to 60C, usually 40-50C) – heated forced-air dryers and low temperature kilns including most heat pump dryers (dehumidifiers).
  • Conventional kilns (usually temperatures of 60-80C for New Zealand pine).
  • Accelerated conventional-temperature kilns operating at temperatures of 80-100C.
  • High temperature kilns (temperatures above 100C, usually 120C or higher).
  • Vacuum drying, which is new to New Zealand, offers the potential of rapid drying and minimising discoloration of high quality lumber.

“Kiln drying is an industrial unit operation used to accelerate the drying of wood. A wood drying kiln is an enclosed space where air speed, temperature and humidity are controlled. Natural air-dying of wood can take weeks, while a wood drying kiln can complete the process in less than a day”¹

The benefit of kiln drying the timber is that it is dried in a controlled environment, has rigorous testing, and is extremely quick giving a higher quality end product. Bugs and insects are also killed during the drying process. Therefore it can be more cost effective and less likely to have distortion, staining or drying stresses (i.e. warping or bowing).

¹Efficient Kiln Drying of Quality Softwood Timber – Murray C McCurdy 2005

What is the best NZ grown timber to use for decks and does it need to be treated?

Any softwood needs to be treated for use as decking except macrocarpa heartwood. Its natural durability can be sufficient for this purpose (although its durability is unreliable in moderate-high decay hazard situations, and occasional failures may occur within 10-15 years).

Most hardwood is naturally durable and resists all kinds of wear and tear. Locally grown eucalypts can be suitable for decking.

The Decking How-to-build guide suggests treated Radiata Pine.

When should pine trees be thinned and pruned?

NZ Wood does not itself carry detailed information related to the growing of trees. However the website of one of our founding partners, the New Zealand Farm Forestry Association, provides a wealth of valuable information resource for those considering embarking in small scale forestry and silviculture.

This website also lists contact details for numerous members and local agencies to which you would be welcome to approach for further advice.

Registered forestry consultants are also available to give advice. They can be found in the Yellow Pages under “Forestry Consultants”.

What is the best density for planting pine seedlings?

NZ Wood does not itself carry detailed information related to the growing of trees. However the website of one of our founding partners, the New Zealand Farm Forestry Association, provides a wealth of valuable information resource for those considering embarking in small scale forestry and silviculture.

This website also lists contact details for numerous members and local agencies to which you would be welcome to approach for further advice.

Registered forestry consultants are also available to give advice. They can be found in the Yellow Pages under “Forestry Consultants”.

What soil conditions do I need for growing pine?

NZ Wood does not itself carry detailed information related to the growing of trees. However the website of one of our founding partners, the New Zealand Farm Forestry Association, provides a wealth of valuable information resource for those considering embarking in small scale forestry and silviculture.

This website also lists contact details for numerous members and local agencies to which you would be welcome to approach for further advice.

Registered forestry consultants are also available to give advice. They can be found in the Yellow Pages under “Forestry Consultants”.