Common Name:

General Information

Agathis australis is an evergreen tree with a narrowly columnar crown when young, becoming globular or flat-topped with age; it can grow 30 - 50 metres tall. The straight, cylindrical bole shows virtually no taper, it can be free of branches for up to 15 metres and 100 - 400cm in diameter. The spreading crown of old trees, relative to their trunk, is immense; it is rather open as the tree ages and is supported on huge branches - the first or lower of these branches can be up to 200cm through where it leaves the trunk[].
The kauri was at one time very highly prized as the source of a high quality timber and also a high quality resin. As a result, the tree was greatly over-exploited. There are too few large trees remaining for commercial exploitation, and most of these are in protected areas. Modern exploitation is largely confined to subfossil deposits from ancient forests where a high quality timber and resin are used mainly for arts and crafts.

Known Hazards

None known

Botanical References

Range

New Zealand - North Island

Habitat

Usually the dominant tree in forests at elevations up to 600 metres[].

Properties

Other Uses Rating
Habit	Evergreen Tree
Height	35.00 m
Growth Rate	Slow
Cultivation Status	Wild

Cultivation Details

Agathis australis is only hardy in the warmer regions of the temperate zone. When dormant it can tolerate occasional short-lived temperatures falling to around -7°c[].
Prefers a deep, fertile, well-drained soil in full sun or light shade[].
Trees begin to bear fertile seed when around 25 - 30 years old[].
Young kauri trees are known as "rickers". They persist in this juvenile form for fifty years or more and can attain a considerable height with their tall thin trunks and narrow pyramid shaped crowns[]
Kauri trees are rather slow growing over their life span although young trees have been recorded as growing at the rate of 35cm per year[].
In even the oldest trees the trunk is kept clean and free of epiphytes by the continuous shedding of small and large flakes of bark which build up in a large mound, 2 metres or more in height, around the base of the tree. This, in time, decays to rich humus and is densely penetrated by the roots of the tree, giving the impression that the tree is growing from it[].
The kauri is among the largest trees in the world. A tree known as 'Tane Mahuta' (Maori for 'Lord of the Forest'), in Waipoua Forest Sanctuary is commonly claimed to be the largest in the species. In 2001, it was measured at 45.2 metres tall with a dbh of 491cm; that number is misleading, though, because the base of the tree is buttressed. The main trunk is 17.8 metres tall and contains 255 cubic metres of wood. The total wood volume, including the crown, is much larger. The enormous crown is nearly 35 metres wide and has a dozen branches over 1 metre in diameter, three greater than 2 metres, and one over 3 metres. Adding the wood in the crown brings the total wood volume up to 516.7 cubic metres, making this tree just a bit larger than the largest known Thuja plicata. Thus Agathis australis is the largest tree in the Araucariaceae and the third largest conifer, after Sequoiadendron and Sequoia[].
There is an extensive patchwork of buried kauri sites found in Northland, especially in coastal regions behind dunes. The buried logs are being 'harvested' for commercial purposes because the wood is perfectly preserved. Some of the buried trees are enormous, with diameters greater than 3 metres. This wood and associated preserved material, represents an immense store of information about past environments, with some buried wood being radiocarbon dated more than 50,000 years old[].

Edible Uses

None known

Medicinal

None known

Other Uses

The bark is fairly thick and exudes a gum, which also flows copiously from any wound to the tree as well as from cones and even, at times, from branchlets and the bases of leaves[].
Before the advent of synthetic resins, the gum was widely used in the manufacture of high quality paints and varnishes. Nowadays it is mainly used in craftwork for making jewelry and related arts[]. Traditionally, the gum was burnt to provide heating and lighting[].
The gum has been obtained in the past by climbing the tree and harvesting lumps that have exuded naturally - often around 5 kilos in weight, pieces up to 25 kilos have been obtained. The bark has also been tapped to obtain the gum. Nowadays most resin is obtained from digging up natural deposits in the soil (mainly swampy soils) from trees that have fallen in the past - sometimes as long as 50,000 years ago[, ].

A powder obtained from the soot of the burnt resin has been used in tattooing[]

The golden-coloured wood, which appears iridescent when properly finished, is light, strong, and easily worked. Thanks to its high resin content it is resistant to decay, and because of the tree's self-pruning ability, the wood is largely free of knots. It was greatly prized in the past for ship masts and spars and for numerous other shipbuilding applications, and was the preferred timber for framing, finish carpentry, and cabinetmaking in its range. It was also used for railway carriages and road paving.
Current exploitation of the wood is focused on the subfossil remnants of past forests preserved in anaerobic sediments, locally referred to as 'swamp kauri'. This wood is well-preserved, but impregnated with minerals which create colours varying from dark brown to green. Such swamp Kauri may be from 1000 to 60,000 years old. Most of this wood is used by craftsmen to produce bowls, fine furniture and the like[, ]
Some of the greatest northern war canoes of the Maori were constructed out of single massive trunks, felled in the forest after elaborate ceremonies, then hollowed out with the use of fire and stone tools. The hulls of canoes made from single trunks in this way were known to reach 25 metres[].

Propagation

Seeds remain viable for only a short period, and usually germinate when they settle in an open situation where light can penetrate readily[].
Cuttings of leading shoots[].