FIELD GUIDE TO NEW ZEALAND’S NATIVE TREES FIELD GUIDE TO NEW ZEALAND’S NATIVE TREES JOHN DAWSON & ROB LUCAS CONTENTS Introduction 7 Conifers 9 Visual key to conifers 14 Tree ferns 51 Flowering trees 67 This book is derived from New Zealand’s Native Trees by John Dawson and Rob Lucas (2012). Visual key to flowering trees 72 The text was abridged and edited by Sue Hallas. The ‘distinguishing features’ boxes were compiled Glossary 426 by Sue Hallas and Cathy Jones. Thanks to Barry Sneddon and Phil Garnock-Jones for contributing the introductions to conifers and flowering trees Further reading 430 respectively. Thanks also to the photographers who supplied photographs as credited in captions. Index 431 First published in 2012 by Craig Potton Publishing Craig Potton Publishing 98 Vickerman Street, PO Box 555, Nelson, New Zealand www.craigpotton.co.nz Text © John Dawson; photographs © Rob Lucas unless specified otherwise. Design and layout: Jane Connor and Karen Jones Cover design: Chris Chisnall ISBN 978 1 877517 82 2 Printed in China by Everbest This book is copyright. Apart from any fair dealing for the purposes of private study, research, criticism or review, as permitted under the Copyright Act, no part may be reproduced by any process without the permission of the publishers. INTRODUCTION WHAT'S SPECIAL ABOUT mountains near the treeline, beech forests are of- New ZEALAND'S NATIVE TREES ten swathed in mist, and with the constant high AND Forests? humidity, water drips from every twig. At these New Zealand’s native trees and forests are unique. high altitudes, the trees are often stunted and con- They look, smell and feel like no other forests, torted, giving these subalpine beech forests, often which is not surprising, as more than 80% of the referred to as cloud forests or goblin forests, an otherworldly feel. c. 2300 native species of conifers, flowering plants Elsewhere in the world, and particularly in and ferns in the flora as a whole occur nowhere subtropical and tropical areas, large, attractively else in the world. This remarkably high level of coloured, flamboyant flowers are common and endemism is one of the reasons for New Zealand designed to attract specialist pollinators, such as being recognised by Conservation International as nectar-feeding birds, long-tongued bees, hawk a world biodiversity hotspot. moths and butterflies. In New Zealand there are not There are two main forest types in New Zealand: many butterflies or nectar-feeding birds, and there conifer–broadleaf and southern beech (Nothofagus). are no native long-tongued bees or hawk moths. One of the most striking features of our conifer– New Zealand has few plant species that attract broadleaf forests is the similarity, in many respects, specialist pollinators, most flowers appearing to be to tropical rainforests. They consist of numerous designed to attract all comers, especially the small species, usually in five strata: emergent trees (mostly flies and moths that are abundant. Consequently, conifers); canopy trees, such as tawa (Beilschmiedia many are tiny, greenish to white, and lack specialised tawa); subcanopy trees, such as nīkau (Rhopalostylis structures that restrict access to all but favoured sapida), and Cyathea and Dicksonia tree ferns; pollinators. As if to make up for the modest little shrubby species and small trees; and ground plants. flowers of most of the species, the fruits that fol- Not only are most species evergreen, they exhibit low are often large, colourful and fleshy, and are features that are typical of tropical rainforest species, eaten by birds. such as: plank buttresses, cauliflory and ramiflory, A number of species of New Zealand trees have a pneumatophores and drip-tips (see glossary). Con- distinctive juvenile form. Perhaps the most remark- spicuous, mostly woody vines are common, as are able of these are the lancewoods (Pseudopanax large epiphytes in tree crowns. crassifolius and P. ferox), in which the juvenile form In comparison to conifer–broadleaf forest, beech has long, narrow leaves that are angled downwards forest has fewer species, predominantly Nothofagus around a slender stem, but the adult form has much spp., and a smaller range of plant lifestyles. Even shorter, broader leaves and a densely branched, though the trees are not leafless in the winter, beech broadly rounded crown. Other remarkable ex- forest is more like temperate forests of the Northern amples of juvenile forms are those that are termed Hemisphere. The sparse undergrowth allows the divaricating. Divarication is usually associated with columns of the tree trunks to be seen, the crowns shrubs, which have a densely twiggy form, with very of trees form the roof of the forest, and the small small leaves, and slender, wiry, interlacing stems leaves, on branches often attractively arranged in with wide-angled branching. However, some tree horizontal layers, allow dappled sunlight through species, including mātaī (Prumnopitys taxifolia) and to the forest floor. kaikōmako (Pennantia corymbosa), have shrubby, New Zealand’s southern beeches are notable tangled, divaricating juveniles that grow into tall, for hosting colourful mistletoe parasites. On wet single-trunked adults. 7 WHAT IS A TREE? ABOUT THIS BOOK Trees are woody, single-trunked plants that can reach Like New Zealand’s Native Trees, from which this many metres in height. It may seem obvious that field guide is derived, the book is arranged in three they are different from shrubs, which are woody, parts: Conifers, Tree Ferns and Flowering Trees. multi-stemmed plants that are relatively short, Within these main parts, which each have a brief growing perhaps 3.5 m tall, often less. However, introduction, species are in alphabetical order. the distinction between these two groups is not Scales have not been included alongside illustra- always clear. tions because of the size variability within species; For many of the species included in Field Guide by referring to the measurements given in the text, to New Zealand’s Native Trees, there is no confu- readers will be able to ascertain the approximate sion; they fit neatly into this definition of a tree. scale. However, in the quick-reference visual guide The difficulty in definition arises with plants that to conifers (pages 14–15), flowering trees (pages are mostly shrubby, with multiple trunks, but oc- 72–97) and certain genera (e.g. Coprosma), leaves casionally become single-trunked specimens of 4 m are shown to scale. or more, such as many of the coprosmas; or where Upward-pointing arrows beside clearcut illustra- some individuals usually considered shrubs develop tions of leaves denote the upper surface; downward- conifers substantial branch systems, reaching heights of 4 pointing arrows, the underside. Illustrations are m or more, such as some olearias. Another unclear numbered sequentially for each species entry; where example is when the trunk is so short that the plant an entry continues over the page, the numbering seldom reaches 4 m and so barely attains the height continues in sequence on the new page. of a tree, for example Cordyline banksii. Can these Locations and months for photographs are not plants justifiably be included in a book on trees? given in this field guide, but this information is In deciding which of these hard-to-categorise included in New Zealand’s Native Trees. species to include in this book, we have generally Where a plant included has been classified as a taken an inclusive approach and incorporated woody ‘threatened’ plant under the New Zealand Threat species that, at least occasionally, grow more than 4 Classification System, its threat status has been m tall and either have a single trunk or substantial given as one of three categories: ‘nationally critical’, woody limbs. There are some exceptions to this ‘nationally endangered’ or ‘nationally vulnerable’. rule, where plants have been included to give more Plants that are designated ‘at risk’ under this system complete coverage to a genus. have not generally been noted. 8 WHAT IS A coniFER? fibrous–stringy, furrowed and often light brown, the blade to the leaf base and is typically short in magnification, may be grouped in whitish, waxy as in tōtara, and peeling away from the trunk in conifers. Scale leaves are small, short leaves that usu- bands or patches on protected leaf surfaces as, for Conifer is a Latin word for ‘cone-bearing’ and alludes long, persistent strips. ally lack a petiole and are pressed against the stem example, in mātaī and Libocedrus spp. to cones being the typical reproductive structure of Conifer wood is referred to as softwood and of their branchlet. Needle leaves are much longer The genus Phyllocladus, which is represented this group of plants. Among other things, they are that of flowering trees as hardwood, because of than scale leaves, narrow, parallel-sided, angular or in New Zealand by three species, is very unusual separated from other plant groups by their scale- their differing hardness. Some exceptions are the flattened in cross-section, and mostly pointed at the among the conifers in that its photosynthetic organs or needle-like leaves, or leaf forms that have been ‘softwood’mātaī , which is extremely hard, and the tip. Broad leaves are also much longer than scale are flattened stem structures called phylloclades. derived from them, and by female or seed cones with ‘hardwood’ whau, which is softer and lighter than leaves, flat in cross-section and often widest at the Small, green leaves are present on seedlings and a unique structure. The great majority of conifers, any conifer woods. The most valued native conifer middle, with curved margins that taper gradually or including all New Zealand species, are evergreen. 1. Bark of mature rimu, showing the distinctive ‘contour- timbers include kauri, tōtara, rimu, mātaī and miro. abruptly towards the base and pointed or rounded map’ pattern of ridges.