By: Ken Mathews

Greening Australia Farm Forestry Support Extension Officer

24/07/2001

Timber Industry Requirements

When selecting tree species for timber production there is a very large range of markets. This diverse range of markets, from pulp to peeler log, each have there own set of quality control measures, which are often backed by legislation and Australian Standards. The timber industry in Queensland is well established and relies heavily on these minimum standards, which must be met by the end product of Farm Forestry. Standards and specifications have been developed to encourage uniformity, to maintain quality and to protect consumers.

These standards should be regarded as the backbone of species selection for timber production. All timbers have characteristics that not only make them unique but also exclude them from certain end uses. In order to select species suitable for any particular market it is necessary to understand some of those constraints.

For the purpose of this exercise our objective will be to identify criteria that determines what timber species are suited to the market we are aiming for. This does not disregard the fact that it is extremely important to understand and allow for site suitability and personal constraints in the process. Knowing what you are trying to achieve right from the planning stages is the first critical step in achieving a successful planting. You will be aiming to avoid unnecessary management, cost and perhaps disappointment further down the line.

Some of the timber properties that should be considered when selecting species for timber plantations are: colour, figure, density, durability and lyctid susceptibility. In addition to these properties some of the end use requirements that should be understood, include: Timber use hazard class, preservative treatment applicable to the end use and seasoning levels that render the timber suitable to the desired application.

Wood Density
Density is the mass per unit volume and for timber is shown in kilograms per cubic meter (kg/m3). Timber density and workability varies with moisture content. The moisture content for air-dry density to be calculated at is 12%. Timber density is a useful indicator of hardness (including workability) and strength.

Very soft = Up to 500 kg/m3 Hard = 800 - 950 kg/m3
Soft = 500 - 700 kg/m3 Very hard = 950 kg/m3 +
Moderately hard = 700 - 800 kg/m3

Durability
The natural resistance of the heartwood of a timber species to decay (rot) and insect attack.Timber can be required to perform in a range of biological hazards and a good service life can be expected by selecting timber with the appropriate natural heartwood durability and preservative of the sapwood.

The following classification system is used to define timber (heartwood) durability.

Class 1 = The highest naturally durable timbers which may resist decay and termite attack for 25 years
or more.

Class 2 = Highly natural durable timber, may have a serviceability span of 15-25 years.

Class 3 = Moderately durable timber, may have a serviceability life span of 5-15 years.

Class 4 = Low naturally durable timbers which may have a serviceability of 1 to 5 years. Timbers within
this class have approximately the same durability as untreated sapwood. All sapwood
irrespective of species is regarded as Class 4.

Durability and Use of Preservative Treated Timber

The heartwood of a few low durability timbers and the non-durable sapwood of most timbers may be rendered serviceable by appropriate preservative treatment. The preservative treatment of timber is carried out to six levels called Hazard Classes, depending on where the treated product is to be used.

Hazard Classes

Hazard Class 1 (H1) = Situations where the timber is continuously dry and under cover. The area is well ventilated and completely protected from weather and dampness. There is no decay hazard present but there is a hazard to lyctid susceptible sapwood. The treatment is designed to stop attack by insects other than termites. E.g. Lyctid beetle.

Hazard Class 2 (H2) = Similar to Hazard Class H1, timber is kept off the ground and completely protected from weather and wetting in a well-ventilated area. The treatment is designed to stop attack by insects, including termites.

Hazard Class 3 (H3) = Timber is exposed to the weather or not fully protected. The timber is clear from the ground and the area is well drained and ventilated. There is a decay and insect hazard and treatment is designed to prevent attack by insects - including termites, and decay.

Hazard Class 4 (H4) = Timber is in contact with the ground or is continually damp so there is a severe decay hazard. The treatment stops attack by insects - including termites, and severe decay.

Hazard Class 5 (H5) = Timber is in contact with the ground, fresh water or in damp or badly ventilated situations. There is a high decay and/or termite hazard and treatment is designed to stop attack by insects - including termites, and very severe decay.

Hazard Class 6 (H6) = Timber is in prolonged contact with seawater. There is a very severe decay hazard. The treatment is designed to stop attack by marine borers and very severe decay.

The susceptibility of timber to attack from Lyctid and other borers

All Pines and the sapwood of (some) hardwood species are immune to lyctid attack. The sapwood of all other lyctid susceptible hardwoods can be rendered non-susceptible to lyctid attack when an approved preservative treatment is used to immunize the timber. The provisions of the Queensland Timber Utilization and Marketing Act 1987-1990 (TUMA) prohibit the sale of lyctid susceptible timbers that have not been immunized, unless specified by the purchaser.

Susceptibility to Queensland Pine Beetle

Hoop, Kauri and Bunya pines are susceptible to attack by the Queensland Pine Beetle when used within the coastal zone of southeast Queensland. Protection against attack in building interiors is achieved by adopting one of the following:

1. Total enclosure in construction
2. Painting or other finishing film of exposed surfaces.
3. Treatment with an appropriate insecticide.
4. Impregnation with a preservative treatment.

Seasoning (Moisture content) of Timber

It is requirements of TUMA, that if timber is to be sold as dried or seasoned, it must either comply with the relevant Australian Standard for the timber or timber products. Where there is no standard, the timber or timber products may have a moisture content of no more than 15% and no less than 10%. Similar restrictions apply to milled products.

Some of the reasons for seasoning (Drying) timber are:

1. Improve timber stability by reducing, shrinkage, cracking, warping and twisting.

2. To improve strength. A pre-requisite to the allocation of seasoned timber strength and joint groups is that the moisture content be no more than 15%.

3. Flooring, paneling, moldings, furniture, joinery and some cladding need to be pre-shrunk prior to use. This pre-shrinking is a requirement under the Timber Utilization and Marketing Act (TUMA). The Act requires that the moisture content of seasoned timber be between 10 and 15% unless this is inappropriate to the Equilibrium Moisture Content (EMC).
Figure 1. Stripping for drying

How Should All This Affect My Species Selection?

Often landholders taking the steps to plan a farm forestry planting have limited knowledge of the industry requirements associated with the markets they are aiming for. They often skip over some of the most common issues facing timber marketing, as they believe marketing is an area that they will be concerned with at a latter stage. It is often simply taken for granted that the infrastructure will magically appear simply because there will be more plantation timber available. Simply planting and hoping for infrastructure should not be the basis of any farm forestry project. In any other industry great care is taken in assuring the end product is suitable for the market. This often requires specific materials, ingredients, tolerances, clearances, etc, etc. The timber industry is no different, "Timbers aint timbers Sol"!!

Farm Forestry is faced with a high level of uncertainty in relation to the end products it will produce. One of the most questioned aspects of farm forestry is whether; young, vigorous; hardwood trees are capable of producing wood of acceptable strength, durability, colour and figure. There is also the concern that fast growing produced from plantations might have substantially more growth stresses and be difficult to cut, season or kiln dry without severe drying degrade (Leggate 1997).

Naturally occurring timbers have strength, colour, figure and durability characteristics, which may not be able to be fully duplicated in faster grown plantation timbers. To a certain extent the timber produced from hardwood plantations will be new product types with characteristics applicable to their growing conditions and management regimes. In many markets the timber will have to prove its worth i.e. it will have to comply with the existing Acts such as TUMA (Queensland) and relevant Australian Standards. More market options will be developed and new marketing approaches will need to be employed. If timber species with higher natural durability, which are also not susceptible to lyctid borer, are chosen for Farm Forestry then the thinnings and final crop will be acceptable for far greater range of markets.

Know what you are dealing with

1. Lyctid susceptibility

Under the Queensland Timber Utilization and Marketing Act all lyctid susceptible sapwood is required to be treated with an approved preservative treatment.
v Are the species I am aiming to plant lyctid susceptible?
v Where is your closest timber treatment plant?
v Will they perform custom treatment for small suppliers?
v If aiming for cabinet or furniture timber do you have access to treatment plants that use Boron or L.O.S.P (Light Organic Solvent Preservative) that will not substantially discolor your timber?
v Have you considered the additional haulage?
v Are you aware of the treatment costs per cubic metre?
v Are you aware that packing and preparing timber into stacks appropriate to the treatment plants requirements will require extra labour and time?
v Are you prepared to sacrifice all sapwood for the sake of avoiding treatment cost?
(This will greatly reduce your sawn timber recovery rates and add extra costs).

2. Will the market require timber that has been seasoned?
If seasoning timber yourself there is additional time, labour and cost in stripping timber.
v Do you have the necessary space?
v Are you aware of the time it takes to air season timber?
v If contracting, where is the closest kiln?
v Have you taken into account the additional haulage and double handling?
v What is the kiln-drying rate per m3?
v Will the local timber merchant contract dry timber?
v How will you ensure that the moisture content is right?
v How will all the above link into the preservative treatment process (Logistics)?

3. Will the proposed end-use require the timber to be dressed?
v Where is the closest planning machine able to profile, e.g. tongue and groove, shot edge?
v Will they contract dress or profile my timber?
v At what cost per lineal metre?
v Have you allowed for an even lower recovery rate after machining?
v How will this link in with treatment and kiln drying (Logistics)?

4. What is the end-use natural durability requirement of my selected markets?
v If one of the markets I am aiming for is poles then timber unless free of sapwood (regardless of lyctid susceptibility must be treated to Hazard Class 5.
v Does the local treatment plant treat to Hazard Class 5?
v If I am hoping to make use of thinnings into round wood such as posts and rails have I chosen species of the appropriate durability?
v If I am aiming to sell delayed thinnings as poles and piles are they of an acceptable species?

5. What is the end-use requirement for density?
v Are the species I am considering too soft for exposed flooring?
v Does the density of the species I am considering limit me to only a few markets?

Setting you objectives and narrowing down the species choice.

Market Selection: One of the main influences on the markets chosen will be the existing infrastructure available within a reasonable haulage distance e.g. 150 km.
Other influencing factors include
Ø What is the scale of other farm forestry projects in my region and what markets have they aimed for?
Ø Am I intending and am I able to value-add to the timber myself?
Ø Is there a timber cooperative in existence within my region?
Ø What are the industry requirements for the range of markets that I am considering?
Ø What are the future plans of local industry?

History of acceptable species
Ø What species have proven their acceptability to the chosen markets?

History of plantation growth success
Ø Investigate the success rate of the above species in farm forestry applications.

What species are the most suitable to your site characteristics?
Ø Soil depth, soil type, pH, rainfall, frosts, etc, etc…

What provenances have proven to be the most successful?
Ø Higher survival rates, less susceptibility to pathogen, improved form, good growth rates, etc, etc

Get to know the market before you make a choice in species.

It is not reasonable to expect that Farm Foresters would outlay hundreds of dollars purchasing Acts and Australian Standards. The cheapest way to find the information relevant to the markets you are aiming for is to talk to the right people. You could also explore the Internet. The Acts of the Queensland Government are freely available (unofficial versions) on the government web site www.legislation.qld.gov.au

Who are the right people?

Ø Sawmill managers who have treatment plants and kilns
Ø Purchasers such as builders, flooring specialists, cabinetmakers and pole and pile suppliers.
Ø Fencing Contractors
Ø Timber merchants who wholesale and retail timber.
Ø State Government agencies such as the Queensland Forestry Research Institute (QFRI)
Ø Timber Research and Development Advisory Council (TRADAC)

The Timber Utilization and Marketing Act, Australian Standards and Building codes have been in place for many years. Farm Forestry in Australia in comparison to other countries is in its infancy.

There is plenty to learn from the industry that will set up farm forestry as a legitimate proposition for landholders. There is ample promotion of the multiple benefits of planting trees and a lot of hype in relation to the forecast returns able to be achieved through timber production. The bottom line when it comes to timber production is what market? Pulp to Peeler, there is a lot in between and a big difference in returns.

For further information contact: Ken Matthews
Farm Forestry Support Extension Officer
Phone: 07 54811795
Mobile: 0428 440 211

Relevant Legislation and Australian Standards

Queensland Timber Utilisation and Marketing Act and Regulations-1987
The Diseases in Timber Act-1975
(Available From Go-Print, Phone: 1800679778)

AS 2209-1994-Timber-Poles for overhead lines
AS 1604-2000-Timber Preservation-Treated-Sawn-round
AS 1684-National Timber Framing Code
AS 1720-1-1997-Timber Structures-Design methods
AS 1720-2-1990-Timber Structures-Timber Properties
AS 2082-2000-Timber-Hardwood-Visualy Stress Grade for Structural Purposes
AS 2796-1-1999-Timber-Hardwood-Sawn and Milled Products
AS 2796-2-1999-Timber-Hardwood-Sawn and Milled Products-Grade Description
AS 2796-3-1999-Timber-Hardwood-Sawn and Milled Products-Timber for Furniture Components
AS/NZS 1080.1:1997-Timber-Methods of test-Moisture Content
AS/NZS 2878:2000-Timber-Classification into Strength Groups
(Available from Standards Australia, Phone: 1300654646)

References

Australian Standard, AS1604. 2000. Timber - Preservative-treated-sawn and round, Standards Australia, Homebush.

Leggate, W. 1997. Evaluation of the Utilisation Potential and Wood Properties of Young, Plantation Hardwoods, QFRI Timber Research.

Queensland Government, 1987. Timber Utilisation and Marketing Act. By Authority, R.G. Giles, Acting Government printer, Queensland

Smith, W.J. et al. 1991. Building Timbers - Properties and Recommendations for their use in Queensland. Technical Pamphlet No. 1, Queensland Forest Service, Department of Primary Industries.