The name “acacia” stands for trees and shrubs of around 1400 species that are native to the tropics and subtropics, of which Australia alone accounts for 950 species. An important species for Europe comes from the Sahel: Acacia senegal. This species provides a resin (gum arabic) which helps the beer to produce a firm head. Another acacia species, Acacia koa, provides the prized koa wood and is only native to Hawaii. All acacias belong to the mimosa subfamily and thus to the large papilionaceous family. In 2005, some of the acacias were classified in new genera. This is how Acacia seyal became Vachellia seyal. Depending on its genetic disposition and site conditions, an acacia can grow into an ornamental shrub or a stately tree. Acacias can reach diameters of up to 90 cm and heights of up to 35 m. Acacia mangium is a popular reforestation species. During rapid growth, it improves the soil by fixing nitrogen. However, it needs plenty of water to thrive; some African species can survive long periods of drought.
The sapwood is cream-colored, while the heartwood varies in color from light gray to red-golden brown to dark brown. Pores scattered, growth ring zones not pronounced. Pores from fine to coarse, depending on the species. Very variable structure, from plain to alternating twisted, often with irregular grain. Decorative.
The spec. weight at a wood moisture content of 12% varies considerably from 0.55 to 1.25 t/m³ depending on species and origin. The swelling and shrinkage values are often high, which makes technical drying difficult. Due to the often high density and hardness, processing is only possible with carbide-tipped tools. Glossy surfaces are then also possible. Good to very good elasticity (modulus of elasticity 11,000 – 23,000 N/mm²), natural durability is usually high.
Wide range of applications: heavy constructions (Australian acacia species), tool styles, turned articles, furniture, components of bows and guitars
| Sources: |
RICHTER & DALLWITZ, 2002, Commercial timber QUEENSLAND, AUSTRALIA (2015) Data sheets, www.daf.qld.gov.au/forestry WOOD DATA Base (2015) latest version |
