A review of Kauri (Agathis australis) nutrition and assessment of current nursery container mixes

Abstract

Kauri forests once covered much of the early land mass of New Zealand. Now only a remnant of the great forests remain-a mere 5% of the pre-European kauri forest has been spared from the axe and burning. Kauri is a large, long-lived tree which normally grows for more than 600 years with individuals exceeding 2 m d.b.h. (diameter at breast height) and often 1000 years of age . Sale in his book, which reviews the history ofthe kauri in New Zealand, states that forest authorities consider this to be the tree capable of yielding the greatest volume of millable timber in the world. Sale goes on to explain the significance of this tree in the early maori history and European colonisation, including its uses and the wastage that has occurred. Fires were particularly common in logged kauri forests, many being deliberately lit by gum diggers . Fortunately some great kauri giants have remained and are protected in reserves and parks. Many are seen as historic and notable trees and have been individually named . The kauri is therefore seen as having great historic and amenity value in New Zealand. Recently there has been a new interest in it as a forestry tree. Early papers have recorded how the kauri is readily produced from seed and also by vegetative propagation. Recent work by Graeme Platt and Jenny Aitken-Christie, funded jointly by the Forest Research Institute and Tasman Forestry, has involved the collection of seed and propagating material from outstanding forest trees. Selected clones have been raised using tissue culture, grafting, and cuttings. Plants grown from seed are reported to be very variable. The kauri is, therefore, seen as having potential in plantation forestry. It is a tree of great beauty and historically its uses have spanned from sailing ship masts to paving slabs, and more recently to furniture where the durable, short-grained, handsome, easily worked and lengthened nature of the kauri wood is used to an advantage.