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Hinau

Hinau has a traditional use by Maori for small implements, such as canoe bailers, spears and also for palisades.

The timber found use for motor-bodies, bridges and house-building, and high-grade hinau was used for boat-building. More recently, the timber was used for Antarctic sled runners. The bark has 20% tannin content, and was employed as a dye.

Description

hinau_90Hinau grows to 15-20 metres, with a fairly broad trunk up to 60cm in diameter, but which rarely exceeds 6-7m in length, with grey-brown bark and shallow longitudinal fissures.

There is no distinction between sapwood and heartwood, with both being a pale off-white colour to dull brown. Similar to tawa, older trees can exhibit a pathological darker ‘heart’, known as ‘black hinau’ which is durable, however, the whitish wood immediately outside the band is non-durable.

Hinau has a fine even texture, with no figure or lustre. Hinau can be found from North Cape southwards to Riccarton Bush in Christchurch on the eastern side of the South Island, and as far south as Parenga on the western side of the South Island in lowland forest up to 750 metres altitude.

Botanical name: Elaeocarpus dentatus

Other common names: Hinau

Strength: Not applicable.

Durability: Black heart hinau is considered durable (i.e. will last 15-25 years in the ground) but this is from past anecdotal experience, not in-ground scientific study. The whitish heartwood is known to be non-durable, an expected to last only 5- 10 years in the ground. The sapwood is perishable and prone to borer attack by the Anobium beetle.

Finishes: Not applicable.

Working properties: Machines well.

Appearance: There is no distinction between sapwood and heartwood, with both being a pale off-white colour to dull brown.

Properties

Hinau dries, machines and finishes well, and can be preservative treated. It has a density of 705kg/m³, and tangential shrinkage from green to 12% moisture content of 7.0%, and radial shrinkage of 2.6%.

Hinau has a modulus of elasticity of 10.4GPa and a modulus of rupture of 89 MPa. Thicker slabs of hinau are prone to checking. Black heart hinau is considered durable (i.e. will last 15-25 years in the ground) but this is from past anecdotal experience, not in-ground scientific study. The whitish heartwood is known to be non-durable, an expected to last only 5- 0 years in the ground.

The sapwood is perishable and prone to borer attack by the Anobium beetle.

One feature of the timber is that it is very slow-burning, even when dry.

Availability

Limited supplies may be available. Refer to the New Zealand Farm Forestry Association website for information regarding local timber suppliers.