Tree and Forest Measurement
P.W. West Tree and Forest Measurement 2 nd Edition With 33 Figures and 11 Tables
P.W. West School of Environmental Science and Management Southern Cross University Lismore, NSW 2480 Australia and SciWest Consulting 16 Windsor Court Goonellabah, NSW 2480 Australia ISBN: 978-3-540-95965-6 e-isbn: 978-3-540-95966-3 DOI: 10.1007/978-3-540-95966-3 Springer Dordrecht Heidelberg London New York Library of Congress Control Number: 2008944019 Springer-Verlag Berlin Heidelberg 2009 This work is subject to copyright. All rights are reserved, whether the whole or part of the material is concerned, specifically the rights of translation, reprinting, reuse of illustrations, recitation, broadcasting, reproduction on microfilm or in any other way, and storage in data banks. Duplication of this publication or parts thereof is permitted only under the provisions of the German Copyright Law of September 9, 1965, in its current version, and permission for use must always be obtained from Springer. Violations are liable for prosecution under the German Copyright Law. The use of registered names, trademarks, etc. in this publication does not imply, even in the absence of a specific statement, that such names are exempt from the relevant protective laws and regulations and therefore free for general use. Cover Photo: Virgin jarrah (Eucalyptus marginata) forest in southwest Western Australia Cover design: WMX Design GmbH, Heidelberg, Germany Printed on acid-free paper Springer is part of Springer Science+Business Media (www.springer.com)
To Mickie, for sharing so much
Preface Since the first edition of this book was published in 2004, two areas of forest measurement have advanced considerably. Concerns about global warming and recognition that forests remove the greenhouse gas, carbon dioxide from the atmosphere and sequester it have led to a flourishing of research on the measurement of forest biomass. Also, substantial technological developments have been made with instruments capable of measuring trees and forests remotely, at scales from individual trees on the ground to large scale images of forests from satellites. Whilst neither of these developments alters the principles of tree and forest measurement fundamentally, both offer new opportunities to take better and/or more costeffective measurements of forests to describe better their role in the world. New discussion of both these areas has been added to this edition. The aim of the book remains to present an introduction to the practice and techniques of tree and forest measurement. It should serve the forestry student adequately in the undergraduate years and be useful as a guide in his or her subsequent professional life. It should allow practising professional foresters to keep themselves abreast of new developments. It aims also to be accessible to landholders and farmers who own and manage forests on their properties, but have no formal forestry education; they may be able to take basic forest measurements and understand the principles of more advanced measurements, which professionals take for them. I have continued to discuss the biological principles which lead to many of the measurements which are made in forests. I believe this will help readers appreciate better why emphasis is placed on the measurement of particular things in forests. Substantial portions of the text have been little altered. However, I have been using the book with my undergraduate forestry students and have made some modifications, where my teaching experience suggests material might be better presented. I am indebted to Prof. H. Wiant for valuable discussion about the new approaches to 3P sampling, as described in Chap. 10. Prof. N. Coops kindly reviewed Chap. 13. Australia January 2009 P.W. West vii
Contents 1 Introduction... 1 1.1 This Book... 1 1.2 What Measurements are Considered?... 2 1.3 Scale of Measurement... 3 2 Measurements... 5 2.1 Measuring Things... 5 2.2 Accuracy... 5 2.3 Bias... 7 2.4 Precision... 8 2.5 Bias, Precision and the Value of Measurements... 8 3 Stem Diameter... 11 3.1 Basis of Diameter Measurement... 11 3.2 Stem Cross-Sectional Shape... 12 3.3 Measuring Stem Diameter... 13 3.4 Tree Irregularities... 14 3.5 Bark Thickness... 15 4 Tree Height... 17 4.1 Basis of Height Measurement... 17 4.2 Height by Direct Methods... 18 4.3 Height by Trigonometric Methods... 18 4.4 Height by Geometric Methods... 20 5 Stem Volume... 23 5.1 Reasons for Volume Measurement... 23 5.2 Exact Volume Measurement... 24 5.3 Volume by Sectional Measurement... 25 ix
x Contents 5.3.1 Sectional Volume Formulae... 26 5.3.2 Tree Stem Shape... 27 5.3.3 Sectional Measurement of Felled Trees... 28 5.3.4 Sectional Measurement of Standing Trees... 29 5.4 Volume by Importance or Centroid Sampling... 30 6 Stem Volume and Taper Functions... 33 6.1 The Functions... 33 6.2 Volume Functions... 33 6.2.1 Volume from Diameter and Height... 34 6.2.2 Volume from Diameter, Height and Taper... 36 6.2.3 Merchantable Stem Volume... 38 6.3 Taper Functions... 39 6.3.1 Examples of Taper Functions... 39 6.3.2 Using Taper Functions... 41 7 Biomass... 47 7.1 Reasons for Biomass Measurement... 47 7.2 Measuring Biomass... 47 7.2.1 Branches and Foliage... 48 7.2.2 Stems... 50 7.2.3 Roots... 50 7.2.4 Carbon Content of Biomass... 52 7.3 Above-Ground Biomass Estimation Functions... 52 7.4 Biomass Estimation Functions for Tree Parts... 58 7.4.1 Allometric Functions... 59 7.4.2 Biomass Expansion Factors... 60 7.4.3 Leaves... 61 7.4.4 Roots... 63 8 Stand Measurement... 65 8.1 Stands and Why They are Measured... 65 8.2 Measurements Taken in Stands... 65 8.3 Age... 66 8.4 Basal Area... 67 8.4.1 Plot Measurement... 68 8.4.2 Point Sampling... 68 8.4.3 Plot Measurement Versus Point Sampling... 71 8.4.4 Practicalities of Point Sampling... 72 8.5 Stocking Density... 73 8.6 Quadratic Mean Diameter... 74 8.7 Dominant Height... 75
Contents xi 8.7.1 Importance of Dominant Height... 75 8.7.2 Measuring Dominant Height... 76 8.8 Site Productive Capacity... 77 8.9 Volume... 80 8.9.1 Plot Measurement... 80 8.9.2 Point Sampling... 81 8.10 Biomass... 82 8.10.1 Root Biomass... 82 8.10.2 Fine Root Biomass and Area... 84 8.10.3 Precision of Biomass Estimates... 85 8.11 Stand Growth... 86 9 Measuring Populations... 91 9.1 Forest Inventory and Sampling... 91 9.2 Subjective Versus Objective Sample Selection... 92 9.3 Population Statistics... 93 9.3.1 Measures of Central Tendency... 93 9.3.2 Variance and Confidence Limits... 93 9.4 Calculating the Population Statistics... 94 10 Sampling Theory... 99 10.1 Sampling Techniques and Their Efficiency... 99 10.2 Sampling with Varying Probability of Selection... 99 10.2.1 The Population Mean and Its Variance... 100 10.2.2 Probability Proportional to Size... 101 10.2.3 Probability Proportional to Prediction... 103 10.3 Stratified Random Sampling... 106 10.4 Model-based Sampling... 108 10.4.1 Applying Model-Based Sampling... 109 10.5 Choosing the Sampling Technique... 112 11 Conducting an Inventory... 115 11.1 Objectives... 115 11.2 Approach and Methods... 116 11.3 Forest Area... 117 11.4 Sampling Units and Calculation of Results... 118 11.5 Systematic Sampling... 120 11.6 Stand Measurement... 121 11.6.1 Shape... 121 11.6.2 Positioning... 121 11.6.3 Size... 122 11.6.4 Edge Plots... 123 11.7 Measurement Errors... 123 11.8 More Advanced Inventory... 124
xii Contents 12 The Plane Survey... 125 12.1 Mapping... 125 12.2 Survey Example... 126 12.3 Conducting the Survey... 126 12.4 Calculating the Survey Results... 129 12.5 Area of a Surveyed Region... 131 12.6 Global Positioning System... 133 13 Remote Sensing... 135 13.1 Ground Measurement... 135 13.1.1 Tree Stems and Crowns Using Lasers... 136 13.1.2 Leaf Area Index Using Sunlight... 139 13.1.3 Roots... 141 13.2 Airborne Measurement... 143 13.2.1 Aerial Photography... 144 13.2.2 Laser Scanning... 146 13.2.3 Spectrometry... 148 13.3 Satellites... 149 References... 153 Appendix A... 171 Appendix B... 179 Appendix C... 181 Appendix D... 183 Index... 185 Erratum to equation 6.13 on page 45... 191 Erratum to equation 10.9 on page 108... 192