Kauri is the common name for a range of species of trees belonging to the genus Agathis. Most species exhibit a juvenile stage of growth with larger foliage than the adult tree.
Click on the thumbnails to see the bigger jpegs.
New Zealand Kauri:
Agathis australis.
It was first discovered by the French expedition of Marion du Fresne in 1772, hence the common name from the New Zealand Maori language is attached to species from Australia, New Zealand and other areas of the Western Pacific.
The kauri's fame as a timber tree grew rapidly after it was discovered because it grew massive volumes of clean grained timber, as well as long straight trunks suitable for the making of spars for the old sailing ships of the eighteenth and ninteenth centuries.The clean grained timber is a result of the way that branches grow from the main stems. The branches are supported by a fleshy swelling which has a thin core of wood in the centre. If the branch dies, the branch is abscised cleanly leaving only a small scar, if any, in the stem from which it falls. This way the tree is able to grow upwards among its siblings and shed branches as they get shaded out, as well as let go any climbing species which might otherwise overwhelm the tree. If the branches get any thicker than about 50mm they cannot abscise and will gradually rot away if they happen to die, hence the kauri is a relatively safe tree as far as falling debris is concerned. The kauri is sometimes refered to as the "widow-maker". This is not due to falling branches but rather the tendency of heavy loads of epiphytes falling off the trees as they were being felled. The bark naturally abscises in big flakes so anything perched in the branches will fall freely if the centre of gravity changes too much.
The growth is strongly terminal dominant, even under poor or uneven light conditions. If the original terminal shoot is lost then it will tend to grow more toward the light, causing the main stem to grow with a lean.
Kauri is often planted as a garden or park tree due to its tidy columnar habit.Each primary school in Taranaki had a kauri tree planted in 1936 which was donated by Sir Victor Davies. The one in the Vogeltown School, New Plymouth, had an unusual shaped cone on it in 1980.
It is propagated from seed, but some selections can be grafted easily, such as a rare golden foliaged form. Seed orchards are sometimes established from grafted plants. The young trees begin to set seed at 15-20 years of age, but good seed set is only achieved with several trees in close proximity, since they are wind pollinated. They may be hand pollinated if the development of the female cones is observed carefully to see when the scales open slightly to catch the windborne pollen. This normally occurs sometime in October-November, with the seed ripening 18 months later, in the autumn. The jpeg above shows the cones in the spring one year after pollination and about six months from maturity.
Cones will form even without pollination, so when seed is gathered it should be sorted to find the fertile ones, which have quite a firm kernel compared to the sterile ones. Seed remains viable for only a short period so is best sown as soon as possible in sterile seed raising mix.
The root system consists of a stong taproot with relatively few fibrous lateral feeding roots. They can be grown in the open ground if planted out as 2 year seedlings and if properly prepared, can be transplanted as quite large plants.
Kauri is quite hardy and will grow as far south as Stewart Island, 47 degrees south, although the natural range is only as far as 38 degrees south latitude.
Pacific Kauris:
Agathis moorei:
This species comes from New Caledonia, and makes a handsome tree if grown in a sheltered place. At Magnolia Glenn it has from time to time been battered around by the wind which tends to knock the big leaflets off, but these are replaced as the next flush of growth develops. It has quite large, broad leaflets which give the branches an almost palm-like appearance in the juvenile stage. It has withstood about 2 degrees of frost with only slight bronzing to the foliage, and fortunately has not been frosted on the new growth it tends to make new growth sporadicly through the year.
It has not responded to atempts to propagate from cuttings.
Agathis macrophylla (obtained as A. vitiensis)
This species is vaguely similar to A.robusta, but is a little more
elegant. It is a vigourous grower, regularly making two flushes of growth per year. It has
been through the same frosts as A.moorei, with no damage at all.
As with the other pacific species, it's growth is more slender than that of A. australis.
It is fairly easy to propagate from cuttings in the autumn, as long as leading laterals only are used. Secondary lateral shoots tend to be very slow in developing anything that resembles a leader.
Agathis sp. (obtained as A.robusta.)
This tree is yet to be positively identified since the foliage and growth habit is more compact than the average plant of A. robusta. The leaflets are smaller than those of A.robusta and arranged around the stem more. It seems to have grown out of its juvenile foliage quite quickly.
Seedling grown Agathis robusta plants are available from
New Zealands leading conifer specialists.
Commercial Horticulture magazine of July 1997 covered Agathis robusta in depth and touched on other species of the genus.
Distribution of the species: