Acacia crassicarpa
Contents
General Plant Info
Acacia crassicarpa, also known as "Thick-podded Salwood", are found as trees 6–25 (–30) m tall, sometimes shrubs less than 1 m tall on coastal dunes.
In its native range, the main flowering season is May – June, but light flowering may occur as late as September. The peak fruiting season is October – November; but there is considerable variation between locations and from year to year
Geographic distribution
Acacia crassicarpa occurs in northern Queensland, the Torres Strait islands, and New Guinea. In Queensland it extends from Badu, Banks, Horn and Prince of Wales Islands in Torres Strait and Cape York Peninsula S to Townsville; southern outliers occur at the Burdekin River (south west of Ayr), Whitsunday Island and from Slade Point near Mackay.
It is most common on sandy, lowland, coastal or near-coastal sites, where it is found on sandy levees near seasonally-dry creeks and on coastal foredune systems.
In New Guinea it occurs in the southern lowlands from south-eastern Irian Jaya, Indonesia, and E to the Oriomo River region of Papua New Guinea.
Identification
The trees are usually between 6 and 25 m tall, but some grow to 30 m. On coastal dunes they tend to be shrubs, sometimes less than 1 m tall. The bark is deeply cracked.
Phyllodes vary from 8 to 27 cm in length, (0.7–) 1–4.5 cm wide, and have about 7 veins more prominent than the rest. Phyllodes normally lanceolate-falcate, narrowly tapered at base above the pulvinus, glabrous, pale green to grey-green; longitudinal nerves numerous and closely parallel (not anastomosing), 4–6 per mm; pulvinus (5–) 8–16 mm long, phyllode lamina blending gradually into the pulvinus.
Pods are oblong to narrowly oblong, flat, woody, (3–) 4–12 cm long, (1–) 2–4.5 cm wide, dehiscing along ventral suture, the nerves transverse to transversely oblique, crowded and numerous.
Seeds traverse, obloid to ovid, glossy black, 5–6 mm long, 3–4 mm wide, +/- terete, arranged separately in separate compartments and their arils are cream to white, ageing cream or pale yellow. Funicle/aril many-folded, 5–20 mm long (unextended), seed is produced in abundance after 4 years. The seeds mature 5–6 months after flowering.
Inflorescence are bright yellow spike, 4–7 cm long, clustered in groups of 2–6 or so in the upper axils. Peduncles 3–10 mm long, glabrous; spikes (2–) 3–7 cm long, +/- interrupted, light golden to pale yellow. Flowers 5-merous; calyx gamosepalous; ovary densely hairy on upper half. The flowers are bisexual. Flowering starts as early as 6 months after the tree is established.
Bark deeply rimose. Branchlets sometimes pendulous, glabrous.
Throughout its range A. crassicarpa is variable in habit and the size of its phyllodes and pods. For example, on Lizard Island, Qld, the type locality, growth habit appears strongly affected by wind shear: small trees with relatively short trunks and spreading canopies are characteristic. Relatively small pods (4–8 cm long; 1.3–2 cm wide) are also typical. A specimen collected from Palfry Island, Qld, has atypically narrow phyllodes (7–8 mm wide).
Alkaloid content
Other uses
This tree is a vigorous nitrogen-fixer and nodulates well. The leaves decompose slowly, and are useful as mulch. The wood from the tree dries out moderately quickly and is useful for firewood and charcoal. It also makes good wood-pulp, better from the softer wood of plantation-grown trees than from the native ones. The sapwood is pale yellowish brown and the heartwood golden brown. The wood is suitable for a wide range of sawn-timber end uses, for light construction, furniture, flooring and boat-building.
Extraction
Cultivation
Suppliers
Established in 1998 on a site on the coastal plain at Conn, near Cardwell in north Queensland, is a high quality Acacia crassicarpa seed production area (SPA). Seed from the Conn SPA became available in 2006.
Contact the Australian Tree Seed Centre for further information and current seed availability.
Plant Industry
Contact Sarah Whitfeld
Phone +61 2 6246 4857
Fax +61 2 6246 4895
Email atsc@csiro.au
Links
http://www.somemagneticislandplants.com.au/index.php/plants/606-acacia-crassicarpa
