PLANTATION SILVICULTURE

Transcription

1 PLANTATION SILVICULTURE

2 FORESTRY SCIENCES Baas P, ed: New Perspectives in Wood Anatomy ISBN Prins CFL, ed: Production, Marketing and Use of Finger-Jointed Sawnwood ISBN Oldeman RAA, et ai., eds: Tropical Hardwood Utilization: Practice and Prospects ISBN X Den Ouden P and Boom BK: Manual of Cultivated Conifers: Hardy in Cold and Warm- Temperate Zone ISBN Bonga JM and Durzan DJ, eds: Tissue Culture in Forestry ISBN Satoo T and Magwick HAl: Forest Biomass ISBN Van Nao T, ed: Forest Fire Prevention and Control ISBN Douglas J: A Re-appraisal of Forestry Development in Developing Countries ISBN Gordon JC and Wheeler CT, eds: Biological Nitrogen Fixation in Forest Ecosystems: Foundations and Applications ISBN Nemeth MV: The Virus-Mycoplasma and Rikettsia Disease of Fruit Trees. ISBN Duryea ML and Landis TD, eds: Forest Nursery Manual: Production of Bareroot Seedlings ISBN Hummel FC, ed: Forest Policy: A Contribution to Resource Development ISBN \ Manion PD, ed: Scleroderris Canker of Conifers ISBN Duryea ML and Brown GN, eds: Seedling Physiology and Reforestation Success ISBN Staaf KAG and Wiksten NA: Tree Harvesting Techniques ISBN Boyd JD: Biophysical Control of Microfibril Orientation in Plant Cell Walls ISBN Findlay WPK, ed: Preservation of Timber in the Tropics ISBN Samset I: Winch and Cable Systems ISBN Leary RA: Interaction Theory in Forest Ecology and Management ISBN Gessel SP: Forest Site and Productivity ISBN Hennessey TC, Dougherty PM, Kossuth SV and Johnson JD, eds: Stress Physiology and Forest Productivity ISBN Shepherd KR: Plantation Silviculture ISBN

3 Plantation silviculture by KENNETH R. SHEPHERD Reader in the Department of Forestry Australian National University Canberra, ACT, Australia 1986 MARTINUS NIJHOFF PUBLISHERS a member of the KLUWER ACADEMIC PUBLISHERS GROUP DORDRECHT / BOSTON I LANCASTER

4 Distributors for the United States and Canada: Kluwer Academic Publishers, 101 Philip Drive, Assinippi Park, Norwell, MA 02061, USA for the UK and Ireland: Kluwer Academic Publishers, MTP Press Limited, Falcon House, Queen Square, Lancaster LAI 1 RN, UK for all other countries: Kluwer Academic Publishers Group, Distribution Center, P.O. Box 322, 3300 AH Dordrecht, The Netherlands Library of Congress Cataloging in Publication Data Shepherd, K. R. (Kenneth Ronald) Plantation silviculture. (forestry sciences) Bibliography, p. Includes index. 1. Tree farms. 1. Title. n. Series ' IS8N-13: e-is8n-13: : / Copyright 1986 by Martinus Nij hoff Publishers, Dordrecht. Softcover reprint of the hardcover 1 st edition 1986 All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, mechanical, photocopying, recording, or otherwise, without the prior written permission of the publishers, Martinus Nijhoff Publishers, P.O. Box 163, 3300 AD Dordrecht, The Netherlands.

5 v TABLE OF CONTENTS Preface Acknowledgements xi xiii CHAPTER 1 INTRODUCTION NATURE OF PLANTATIONS Plantations Defined Monoculture Tree Crops plantations and Long Term Productivity PLANTATIONS, ECONOMICS AND LAND USE COSTS AND BENEFITS Land as a Resource Plantations and Development SILVICULTURE AS BOTH ART AND SCIENCE SILVICULTURAL SYSTEMS CHAPTER 2 SEED PRODUCTION 12 THE NEED FOR GOOD QUALITY SEED THE REPRODUCTIVE CYCLE IN FOREST TREES Development of Gymnosperm Seeds Development of Angiosperm Seeds FACTORS INFLUENCING FLOWERING AND SEED PRODUCTION SEED PRODUCTION FROM THE NATURAL FOREST OR FROM PLANTATION SEED ORCHARDS Siting of Seed Orchards Orchard Establishment Orchard Management CHAPTER 3 SEED HANDLING 41 TRADE IN SEED SEED COLLECTION Pre-collection Planning Field Collection Methods Precautions at Harvest to Minimise Disease Infection Labelling the Crop SEED EXTRACTION DRYING AND STORAGE OF SEED Seed Quality Moisture Content Seed Storage SEED TESTING Sampling the Seedlot Physical Characteristics of the Seed Sample Weight Moisture content Genuiness and origin Seed Germination Tests

6 vi SEED DORMANCY AND PRE-SOWING TREATMENT Immaturity of the embryo Complete inhibition of water absorption A state of dormancy in the embryo itself Secondary dormancy CHAPTER 4 NURSERY PRACTICE 64 SEEDLINGS FOR PLANTING THE NURSERY SITE Selection of a Nursery site Layout of the Nursery BARE-ROOT SEEDLING PRODUCTION The Nursery Soil Texture Structure Nutrients Organic matter Soil reaction, or ph Mycorrhiza Soil Management Tillage Fertiliser use Maintaining soil organic matter Adjusting soil ph Pest and disease control Irrigation Seedbed preparation, Sowing and Maintenance Sowing Weed control Pre-emergence weed control Post-emergence control Interrow Cultivation Root Pruning and Root Wrenching Nutrient Deficiency in the Seedbed Nitrogen Phosphorus Potassium Magnesium Lifting, Packing and Transport of Bare-root Stock Lifting Packing Transport PRODUCTION OF CONTAINER STOCK Choice of Container Cost of the container Weight when filled with a growing medium Durahili ty Effects on the root system Choice of Growing Medium Fumigation and Sterilization of Potting Mixtures Sowing Seed or Pricking out into Containers Shading Low~shade High shade Disease Control

7 vii Watering Hardening-off Handling and Transport ASEXUAL OR VEGETATIVE PROPAGATION Propagation by Cuttings Grafting and Budding Tissue Culture PLANTING STOCK QUALITY NURSERY RECORDS CHAPTER 5 PLANTATIONS AND LAND-USE 109 PLANTATIONS AND CONSERVATION SITE EVALUATION CLIMATE Soil and Terrain Market and Economic Considerations Existing and potential markets Availability of infrastructure Labour supply Scale of operations 117 Environmental Impacts of Plantation Establishment 117 Hazards of fire, wind, erosion and landslide 118 Hazards of a biological nature 118 Conservation of native plants and animals 118 Problems of stream sedimentation and loss of water quality 118 Soil compaction and loss of fertility 118 Adverse impacts on landscape values 118 Adverse impacts on recreational values 119 SITE QUALITY 119 PLANTATION DESIGN Plantations and Landscape Planning the Access System Stage construction Classification of plantation roads Roading density Compartment shape Non-wood Production Plantations Windbreaks and shelterbelts Urban forestry Farm forestry and agroforestry CHAPTER 6 GROWTH OF EVEN-AGED CROPS 133 TREE STANDS, AND MONOCULTURES GROWTH OF SINGLE STEMS Height Growth Free or indeterminate growth Fixed or determinate growth Diameter Growth Root Growth Tree Form and the Influence of the Tree Crown GROWTH OF THE FOREST STAND Competition, Tolerance, Dominance and Crown Class Competition Tolerance

8 viii Dominance and crown class Heigh t Growth Diameter Growth Root Growth STAND GROWTH AND STOCKING DENSITY BIOMASS PRODUCTION CHAPTER 7 PLANTING, SITE PREPARATION AND MAINTENANCE SILVICULTURAL DECISIONS SITE PREPARATION METHODS Clearing the Land Broadcast felling and burning Felling, windrow clearing and burning Drainage and Mounding Drainage Mounding Deep Ripping the Planting Site Ploughing and Screefing Weed Control on the Planting Line Fertilizing at Planting Benefits of adding fertilizers Forms of fertilizer used at planting Economics of fertilizer use at planting Legumes as a source of nitrogen MAINTAINING SITE PRODUCTIVITY Loss of Nutrients Direct loss of nutrients in harvested biomass Indirect loss of nutrients from the site Water Relations and Second Rotation Sites Improving the water holding capacity of the soil Increasing tree crop water usage Soil Compaction Managing the Nitrogen Supply CHAPTER 8 PLANTING AND EARLY MAINTENANCE 201 CHOICE OF SPECIES purpose of the Plantation Plantings primarily for wood production Plantations for protection Plantations for fuelwood and fodder Amenity and urban planting Site and Climate Use of Indigenous Species Use of Exotic Species CHOICE OF ESPACEMENT Espacement, Tree and Stand Growth Mortality Height Diameter growth Stem form Bral}ch size Volume production Wood quali ty Effects of Initial Espacement on Costs

9 ix PLANTING Timing of Planting Operations Special Forms of Planting Agro-forestry Taungya, or trees with food crops Line planting, or line enrichment planting urban plantings Planting Methods PROTECTION AND EARLY MAINTENANCE Protection from Vermin Watering and Water Conservation Minimising Competition from other Vegetation Applicatiion of Fertilizer CHAPTER 9 PRUNING 225 REASONS FOR PRUNING NATURAL PRUNING ARTIFICIAL PRUNING Methods of pruning Axe pruning Saw pruning Shear pruning High pruning Mechanical pruning Timing and Intensity of Pruning PRUNING AND WOOD QUALITY CHAPTER 10 THINNING 236 THINNING AND GROWTH OF STANDS OBJECTIVES OF THINNING National or Organisational Objectives Financial Considerations Integration of Forest and Industry Biological Considerations THINNING METHODS Commencement of Thinning Type of Thinning Low thinning Crown thinning Selection thinning or thinning from above Mechanical thinning Free thinning Thinning Interval Thinning Intensity Severity of Thinning THINNING, HARVESTING AND THE ENVIRONMENT WIND STABILITY AND THINNING THINNING AND WOOD QUALITY CHAPTER 11 SILVICULTURAL MANAGEMENT 263 TACTICS AND STRATEGIES IN SILVICULTURE A SILVICULTURAL REGIME Shorthand Notation for a Silvicultural Regime

10 x Factors Influencing a Choice of Regime Silvicultural Prescriptions Use of Systems Analysis to Determine Regimes Recognition 271 Definitiion of the extent of the problem and its boundaries 271 Identifying the hierarchy of goals and objectives 272 Generation of solutions 272 Modelling 272 Evaluation of potential courses of action Implementation of the results MODELS FOR EVALUATING SILVICULTURAL ALTERNATIVES The Data Base Data for building a model Data for using a model Yield Simulation Models Economic Analysis of the Results of Simulation Present net value Internal rate of return Benefit cost ratio Seeking Optimum Management Strategies SILVICULTURAL REGIMES TO SUIT DIFFERENT MANAGEMENT OBJECTIVES Maximum Production Regimes with a small wood market with no small wood market Maximum Value Regime An Agro-forestry Regime A Regime for Windy Climates PLANTATIONS AND THE FUTURF INDEX REFERENCES

11 xi Preface Plantations of a wide range of tree species have assumed an important place in our world, providing wood for industry, fuelwood and animal fodder, protection from adverse environments and for the soil, as well as amenity and aesthetically pleasing landscapes. silvicultural knowledge of this particular branch of forestry first developed in Europe more than two centuries ago but in many parts of the world is still in a process of rapid evolution as more and more plantations are established to meet specific needs. The first exotic tree species to be established in plantations in my own country were planted more than a century ago and, likewise, New Zealand has a long history of planting. Both countries have developed a vigorous and innovative approach to plantation practice, soundly based initially on European experience but gradually modified to meet the challenges of new environments, new markets, and changed economic circumstances. This book on plantation silviculture was begun some years ago when the lack of a suitable undergraduate text for teaching purposes became apparent. The present text is aimed essentially at this audience. Although I have drawn heavily on the experience of Australia and New Zealand, the principles outlined are applicable anywhere in the world where plantations are being grown and tended, from the United States and Scandinavia to India, South Africa or Brazil. The text should also serve as a useful reference to advanced students and practicing foresters, with the reference list providing an introduction to the literature on this subject. The book is organised into eleven chapters, including an introduction in which plantations and plantation silviculture are defined and the significance of plantations in land-use and national development are outlined. The importance of economics in modern plantation practice is introduced here, but taken up in greater detail in the final chapter. Two chapters are devoted to seed production, collection, and storage, an important part of good plantation practice. Increasingly, seed for plantation establishment is being produced in seed orchards, replacing collections from natural forests as these shrink in area and making it possible to take advantage of the benefits of tree breeding in new crops. There follows a chapter on nursery practice which deals mainly with the production of planting stock from seed. A chapter deals with the evaluation of land for plantation purposes, on the basis that a prior landuse decision has been taken to allocate the land to this particular use. The latter part of the chapter deals with the design of plantations to occupy the land, a subject which has received relatively little treatment in the literature. Landscape aspects of plantation design have received some attention but surprisingly little attention has been given to road systems, considering the amount of investment involved. Chapter 6 is devoted to the growth of even-aged tree crops and might at first glance seem out of place in this book. However, an explanation of the stand dynamics of even-aged, monoculture crops is difficult to find in the literature and, to this author's knowledge, has

12 xii not been brought together before in a way which would assist in devising silvicultural practice for plantations. This chapter precedes those on site preparation, planting, pruning and thinning which we would naturally expect to find. These four chapters suggesting suitable forms of silvicul tural practice in a wide range of situations rely heavily on an understanding of the ways in which monoculture crops develop. The chapter on site preparation has been extended considerably to deal with the problem of maintaining producti vi ty in the long term. This problem has been evident for more than a century in parts of Europe and has assumed considerable significance more recently in parts of Australia and the United States where plantations have been established on soils of coarse texture and of low fertility. The final chapter is an attempt to bridge the gap between silvicultural practice and forest management. Titled 'Silvicultural Management', this chapter explores some of the issues other than of a strictly silvicultural nature, such as site, climate and species etc., which can influence the determination of silvicultural and management decisions, for example markets, interest rates and time. The advent of computers has made it possible for the forest manager to explore much more carefully the consequences of adopting alternative silvicultural regimes than was possible only a decade or more ago. Such analyses will include an investigation not only of the effects of alternative practices on growth and yield but also on the financial consequences. Simulation and optimisation techniques can be used to suggest the course of action most likely to achieve the objectives set for a particular plantation enterprise and for management to be able to re-evaluate strategies should one or more of the important factors which influence the decision making process change for one reason or another. Economic evaluation of plantation enterprises has become more stringent in recent times and the silviculturist certainly must recognise the economic realities of the world in which the plantation has to operate and to attempt to work wi thin the restrictions which this will impose. At the same time, the forest manager and economist must recognise that the plantation enterprise they manage can only operate successfully wi thin set biological limits and, if pushed too far outside these limits, can easily collapse. This book attempts to explain what these limits are and to highlight the need for consultation between silviculturist and manager in the decision making process to ensure the success of the enterprise.

13 xiii Acknowledqements A book cannot be written without a considerable amount of assistance for which I express my gratitude. In the Department of Forestry, at the Australian National University, the staff have all given assistance in some way or another but I would particularly thank Beverley Hawkins, Audrey Maher, Liz Robinson and Jo Roper for typing, and Judy Ledjins, Joe Miles, Geoff Mitchell and Terry Raath for technical assistance. Ian Heywood I s excellent drafting was converted to equally excellent photographs by Marie Col viii of the Science Photographic Unit, with advice from Ivan Fox. I was fortunate to be an academic visitor for a semes ter in the CSIRO Di vision of Fores t Research, with access to the excellent library and the willing assistance of the staff. The Seeds section of the Division assisted considerably with illustrative material for the chapters on seed. My colleagues Neil Byron, Partep Khanna, Norman Lewis, Leon Pederick and Brian Turner gave valuable advice on parts of the manuscript. The interest in plantation forestry throughout the world is amazingly wide and diverse. I am indebted to the host of forestry colleagues in many parts of the world who have given so willingly of their time to show me plantation forestry in so many of its different forms. The first was Dr. Max Jacobs who introduced me as an undergraduate to forestry as a career and, in particular, to plantation forestry. Finally, my sincere thanks to my wife Audrey who has assisted in so many ways but most importantly has given great support and encouragement to me to see the task to an end. Canberra, April, 1986.