GPEMS

Manna Gum

Botanical name : Eucalyptus viminalis

Origin

Manna Gum grows in the cooler areas of South Australia, Tasmania, Victoria and the tableland districts of New South Wales.

Trading names

Manna Gum and viminalis

Appearance Heartwood : pale pink or pale pinkish brown.

Sapwood of similar colour and not distinct.

Texture:medium and even.

Grain : variable.

Growth rings prominent.

General comment

Difficult to dry.

Prone to internal honeycombing, surface checking and collapse.

Reconditioning desirable.

Easy to work.

Glues satisfactorily.

Predrill when nailing near the end of boards.

Common uses

General construction.

Properties

Hardness rating :Average Hardness Rating - Dry: Moderate

The hardness rating of a timber species is measured by the Janka Test. This is a standard test which measures the penetration into the timber of a common load and projectile. The results relate to a hardness capacity of the material and are expressed in kN. This information is useful where the timber may be subject to potential damage from impacts e.g. a dance floor. There are 2 sets of published figures; one for 'Green' or freshly felled timber and one for seasoned timber - i.e. timber with a moisture content of 12%.

The ratings given here are: Soft - less than 5.5 Moderate - 5.5 to 7.0 Hard - 7.1 to 10.0 Very Hard - greater than 10.0.

Lyctid Susceptibility of Sapwood : Susceptible(source AS 5604)

Only the sapwood of some hardwoods is susceptible to lyctid borer attack. No softwoods are susceptible to attack.

Termite Resistance of Heartwood (inside above ground) : Not resistant(source AS 5604)

Marine Borer Resistance of Heartwood : Class 4 (source AS 5604)

Natural Durability Rating of Heartwood Above Ground : Class 3(source AS 5604)

Natural Durability Rating of Heartwood In-Ground Contact : Class 4(source AS 5604)

Natural durability ratings: The natural durability rating of a timber species is a rating of the timber's resistance to attack by wood destroying fungi and wood destroying insects. The sapwood of all timber species has poor resistance and so the natural durability rating applies only to the heartwood of a timber species. The rating is based on the testing of stakes and poles embedded in the ground and on expert opinion of historical performance. There are 2 sets of ratings: one for above ground use and one for in-ground contact use. The lower the number the higher the performance in terms of durability. This information is useful for specifying material for external or exposed applications.

Density: 'Green Density' (GD) is the density of the wood at the time the living tree is felled. It varies considerably with the season, weather conditions, the age of the tree and so on; the quoted figure must therefore be accepted as a guideline only and when accurate green density figures are required for, say, assessment of transport costs, it is advisable to carry out accurate determinations on the materials involved.

'Dry Density' or 'Air Dry Density' (ADD) is the average density of the wood at 12 per cent moisture content. It too varies with conditions of growth, climate and maturity of wood. There are published figures for both Green Density and Air Dry Density of most commercial species. The figures given above have been rounded to the nearest 50.