Botanical Name: Agathis robusta
Species: A. robusta
Synonyms: Agathis palmerstonii
Common Names: Queensland Kauri,Queensland kauri pine or Smooth-barked kauri
Habitat: Agathis robusta is native to Australia – Queensland. It grows in the Rainforests ( near sea level to (in the N) 900 m. )
Agathis robusta is a large evergreen tree growing straight and tall to a height of 30–50 m, with smooth, scaly bark. The leaves are 5–12 cm long and 2–5 cm broad, tough and leathery in texture, with no midrib; they are arranged in opposite pairs (rarely whorls of three) on the stem. The seed cones are globose, 8–13 cm diameter, and mature in 18–20 months after pollination; they disintegrate at maturity to release the seeds. The male (pollen) cones are cylindrical, 5–10 cm long and 1-1.5 cm thick.
This species tolerates temperatures down to about -7°c in Australian gardens, though this cannot be translated directly to British gardens due to our cooler summers that often do not fully ripen new growth and our longer colder and wetter winters
Seed – it cannot tolerate desiccation and does not store for much more than 2 months in normal conditions. It does not require pre-treatment. Sowing is done with the wing part of the seed pointing upwards and 66% of the seed buried in the soil. Germination commences within 6 days, with 90 – 100% germination rates within 10 days. Cuttings of leading shoots.
The Queensland kauri was heavily logged in the past, and spectacular trees of prodigious size are much rarer than in pre-European times; despite this, the species as a whole is not endangered.
The plant yields a fibre or canes. A fibre obtained from the inner bark is used to made ropes and nets.
The bark yields a resin known as dammar – used for making varnish etc.
Dammar is a hard resin, obtained from various trees of Southeast Asia. Traditionally, it is used for purposes such as caulking boats and baskets, as an adhesive, a medicine, as a fuel for torches and sometimes in foods. Dammar has many commercial applications, though many of these uses are less important nowadays due to the advent of synthetic materials. Commercially, it is an ingredient of inks, lacquers, oil paints, varnishes etc, and is used as a glazing agent in foods
Harvesting of the resin commences when the bole is around 25cm in diameter (approx 20 years old). Triangular cuts (becoming circular with age) are arranged in vertical rows around the trunk. The cuts are several centimetres wide at first, but become enlarged at every tapping and eventually become holes of 15 – 20cm in depth and width. The average number of holes for a tree about 30 metres tall and 60 – 80cm in diameter is 9 – 11 in each of 4 – 5 vertical rows. For the higher holes, the tapper climbs the tree supported by a rattan belt and using the lower holes as footholds.
The exuded resin is allowed to dry on the tree before it is collected. The frequency with which the tree is visited to refreshen the cut varies from once a week to once a month, depending on how far the tree is from the village. Tapping can continue for 30 years.
The heartwood is a pale cream, golden brown, to dark reddish or yellowish brown if resinous; it is usually not distinct from the sapwood. The wood is lustrous; the grain mainly straight; texture fine and uniform; generally without distinctive odour or taste. It is soft, strong, somewhat durable, vulnerable to termite attack and prone to blue stain. It works easily with hand and machine tools, finishes with a clean smooth surface; has good nailing and screwing properties; good veneer peeling characteristics; paints and polishes well; easy to glue. It is used for a range of purposes, including vats and tanks, patternmaking, millwork, boatbuilding, furniture components, face veneers, shingles and pencil slats.
Disclaimer : The information presented herein is intended for educational purposes only.