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.
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.
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.
Creating secure environments
Waipoua is home to Tane Mahuta, king of the forest and the largest remaining kauri tree in the country. The 1500 year old Tane Mahuta is 51.5 metres tall, with a girth of 13.77 metres. The second and third largest kauri trees can also be found in the Waipoua Forest: Te Matua Ngahere and the McGregor Kauri.
The forests of Waipoua are vitally important refuges for threatened wildlife. The endangered North Island kokako and the North Island brown kiwi both live here. More abundant are the kukupa/kereru ( New Zealand wood pigeon), fantail, pied tit, tui, grey warbler, shining cuckoo and kingfisher. Another distinctive creature is the large and very handsome kauri snail, a carnivore which feeds mainly on earthworms, slugs and soft-bodied insects.
A lasting reminder of the once-thriving kauri industry are the kauri dams. Kauri driving dams were built by loggers to drive large quantities of kauri logs downstream from remote areas. While they played a major role in the destruction of the forest, they were also impressive engineering feats, built without drawings or detailed calculations, yet able to withstand the pressure of tonnes of water and kauri logs which were swept through with tremendous force when the dam was tripped.