|
Agathis australis, known as the kauri, is a coniferous tree native to the northern districts of the North Island of New Zealand and is the biggest but not tallest species of tree in the country. The tree has smooth bark and small oval leaves. Other common names to distinguish Agathis australis from other members of the genus are southern kauri and New Zealand kauri. Young plants grow straight upwards and have the form of a narrow cone with branches going out along the length of the trunk. However, as they gain in height, the lowest branches are shed to prevent epiphytes from climbing. By maturity, the top branches form an imposing crown that stand out over all other native trees, dominating the heights of the forest.
The flaking bark of the kauri tree defends it from parasitic plants, and accumulates around the base of the trunk. On large trees it may pile up to a height of 2m or more.(Reed 1953, p. 60) The kauri has a habit of forming small clumps or patches scattered through mixed forests. (Reed 1953, p. 74)
Kauri leaves are 3 - 7 cm long and 1 cm broad, tough and leathery in texture, with no midrib; they are arranged in opposite pairs or whorls of three on the stem. The seed cones are globose, 5 - 7 cm diameter, and mature 18 - 20 months after pollination; the seed cones disintegrate at maturity to release winged seeds, which are then dispersed by the wind. While the reproduction of kauri seed cones takes place between male and female seed cones of the same tree, fertilisation of the seeds occurs by pollination, which may be driven by the same or another tree's pollen.
Kauri forests are among the most ancient in the world. The antecedents of the kauri appeared during the Jurassic period (between 190 and 135 million years). |