Agathis

From Wikipedia, the free encyclopedia
Jump to: navigation, search
Agathis
Agathis australis (New Zealand kauri)
Scientific classification
Kingdom: Plantae
Division: Pinophyta
Class: Pinopsida
Order: Pinales
Family: Araucariaceae
Genus: Agathis
Salisb.
Species

See text

Distribution of Agathis species.

The genus Agathis, commonly known as kauri or dammar, is a relatively small genus of 21 species of evergreen tree. The genus is part of the ancient Araucariaceae family of conifers, a group once widespread during the Jurassic period, but now largely restricted to the Southern Hemisphere except for a number of extant Malesian Agathis.[1]

Description[edit]

Bark of Agathis robusta at Melbourne Royal Botanic Gardens (leaves belong to another plant)

Mature kauri trees have characteristically large trunks, forming a bole with little or no branching below the crown. In contrast, young trees are normally conical in shape, forming a more rounded or irregularly shaped crown as they achieve maturity.[2]

The bark is smooth and light grey to grey-brown, usually peeling into irregular flakes that become thicker on more mature trees. The branch structure is often horizontal or, when larger, ascending. The lowest branches often leave circular branch scars when they detach from the lower trunk.

The juvenile leaves in all species are larger than the adult, more or less acute, varying among the species from ovate to lanceolate. Adult leaves are opposite, elliptical to linear, very leathery and quite thick. Young leaves are often a coppery-red, contrasting markedly with the usually green or glaucous-green foliage of the previous season.

The male pollen cones appear usually only on larger trees after seed cones have appeared. The female seed cones usually develop on short lateral branchlets, maturing after two years. They are normally oval or globe shaped.

Seeds of some species are attacked by the caterpillars of Agathiphaga, some of the most primitive of all living moths.

Uses[edit]

Various species of kauri give diverse resins such as kauri copal, Manilla copal and Dammar gum. The timber is generally straight-grained and of fine quality with an exceptional strength-to-weight ratio and rot resistance, making it ideal for yacht hull construction. The wood is commonly used in the manufacture of low priced guitars due to its good resonating properties, yet relatively low price of production. It is also used for some Go boards (goban). The uses of the New Zealand species (A. australis) included shipbuilding, house construction, wood panelling, furniture making, mine braces, and railway sleepers.

Species list[edit]

Picture gallery[edit]

References[edit]

  1. ^ de Laubenfels, David J. 1988. Coniferales. P. 337–453 in Flora Malesiana, Series I, Vol. 10. Dordrecht: Kluwer Academic.
  2. ^ Whitmore, T.C. 1977. A first look at Agathis. Tropical Forestry Papers No. 11. University of Oxford Commonwealth Forestry Institute.

External links[edit]