Timber- Forests, Plantations, Production and Sustainability

1. Sustainability

1.1. Timber is renewable, biodegradable, stores carbon and is more energy efficient to produce than steel, concrete or aluminium.

1.2. ‘Natural’ materials are generally preferable to synthetic, however some natural materials can have significant environmental and health impacts, such as timbers treated with chemicals against biological attack and to increase durability.

1.3. Sustainable yield is the quantity of timber or other product that can be harvested from a forest while ensuring that the functioning of the forest ecosystem as a whole is maintained and the flow of products is continuous in perpetuity.

1.4. Australia continues to import wood from overseas countries as demand outstrips supply. The major environmental concern regarding imported wood is that up to 10% comes from illegal logging, that is, sources that are not certified or regulated and may be harming habitats for endangered animals and poor (low-income) forest dependent communities

2. Timber Products

2.1. Timber products are manufactured using smaller pieces of timber, wood chips or saw dust and glue. Less timber overall is required to make products which are lighter and stronger than timber. Composites products are manufactured using either epoxy or formaldehyde glue. Both of these can emit trace quantities of chemical vapours and gases in our homes and buildings.

2.2. The conversion-rate from tree to useful material can be 80-90% for these composite products, compared with only about 40% for solid timber.

3. Types of Reconstituted Timber Products

3.1. Medium Density Fibreboard (MDF) MDF is a glued timber product, usually manufactured from plantation thinnings. MDF products can also be given a solid wood appearance by wrapping the MDF in a wood veneer.

3.2. Particle Board/ chipboard Wood is present as small particles and flakes, not reduced to fibre. Particle board and chipboard can be veneered with hardwood. Particle board can be recycled.

3.3. Engineered Wood Engineered wood, such as Hardlam, is reconstituted wood- fibres, wood chips and shavings, glued back together in a block and used for structural and appearance grade products. It is made by sticking veneers together, and can be made from smaller trees. Modern veneers use relatively small amounts of timber – thus making them more resource efficient and replacing old growth hard wood.

3.4. Plywood Plywood is made from a number of glued layers of wood veneer. The grain of every second layer is rotated at Right Angles, called Cross Banding. Glues used in plywood manufacture can have emissions which are potential health hazards. Plywood can be recycled.

4. Native Forests

4.1. Native forests are the naturally occurring treed areas that are managed for sustainable timber production. Eucalypt is Australia's most common native Hardwood tree.

4.2. Native forests provide almost all of Australia’s hardwood for products such as furniture, flooring, appearance and structural grade timbers. Typical rotation times can stretch to more than 100 years.

4.3. Some of the effects of logging native forests are: Soil erosion Salinity Extinction or endangerment of other plants and animals

5. Plantations

5.1. Plantation forests are those significant areas planted with specific varieties of trees for the purpose of timber production. Radiata Pine is the most common Softwood grown in plantations in Australia.

5.2. Plantations provide a controlled supply of timber and are considered a somewhat renewable resource as trees can be replanted. Some pine species can be harvested after 30 years.

5.3. Plantation timbers are cheaper than forest timbers and plantations produce about two-thirds of Australia’s log supply.

6. Growing Timber

6.1. Native forests and plantation forests provide different products. High quality hardwood comes from native forests. Plantations provide softwood and lower quality hardwood, which is predominantly used for paper products.

6.2. Only around 35% of hardwood and 45% of softwood logs are converted into timber. By products are wood chips or sawdust, which are made into timber products.