Forest Mensuration

389 Pages·2007·10.08 MB·English

by  Anthonie van Laar, Alparslan Akça

FOREST MENSURATION
Managing Forest Ecosystems
Volume 13
Series Editors:
Klaus von Gadow
Georg-August-University,
Göttingen, Germany
Timo Pukkala
University of Joensuu,
Joensuu, Finland
and
Margarida Tomé
Instituto Superior de Agronomía,
Lisbon, Portugal
Aims & Scope:
Well-managed forests and woodlands are a renewable resource, producing essential raw material
with minimum waste and energy use. Rich in habitat and species diversity, forests may contribute to
increased ecosystem stability. They can absorb the effects of unwanted deposition and other
disturbances and protect neighbouring ecosystems by maintaining stable nutrient and energy cycles
and by preventing soil degradation and erosion. They provide much-needed recreation and their
continued existence contributes to stabilizing rural communities.
Forests are managed for timber production and species, habitat and process conservation. Asubtle
shift from multiple-use managementtoecosystems managementis being observed and the new
ecological perspective of multi-functional forest managementis based on the principles of ecosystem
diversity, stability and elasticity, and the dynamic equilibrium of primary and secondary production.
Making full use of new technology is one of the challenges facing forest management today.
Resource information must be obtained with a limited budget. This requires better timing of resource
assessment activities and improved use of multiple data sources. Sound ecosystems management,
like any other management activity, relies on effective forecasting and operational control.
The aim of the book series Managing Forest Ecosystemsis to present state-of-the-art research
results relating to the practice of forest management. Contributions are solicited from prominent
authors. Each reference book, monograph or proceedings volume will be focused to deal with a
specific context. Typical issues of the series are: resource assessment techniques, evaluating
sustainability for even-aged and uneven-aged forests, multi-objective management, predicting forest
development, optimizing forest management, biodiversity management and monitoring, risk
assessment and economic analysis.
The titles published in this series are listed at the end of this volume.
Forest Mensuration
By
Anthonie van Laar
Somerset West, South Africa
and
Alparslan Akça
Universität Göttingen, Germany
AC.I.P. Catalogue record for this book is available from the Library of Congress.
ISBN-13 978-1-4020-5990-2 (HB)
ISBN-13 978-1-4020-5991-9 (e-book)
Published by Springer,
P.O. Box 17, 3300 AADordrecht, The Netherlands.
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© 2007 Springer
No part of this work may be reproduced, stored in a retrieval system, or transmittedin any form
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use by the purchaser of the work.
Anthonie van Laar was born in the Netherlands in 1923. He studied forest
scienceattheUniversityandResearchCentreWageningenbetween1941and
1949. In 1958 he emigrated to South Africa and obtained his D.Sc. degree in
Forest Science at the University of Stellenbosch (1961), thereafter Dr.oec.pub
(1973), and Dr.hab. (1979) at the University of Mu¨nich. His theses dealt with
forest biometry and growth modeling. Since his retirement in 1988, van Laar
continuedhisinvolvementinthesesubjects,moreparticularlyingrowthmodels
forEucalyptusgrandis.
Alparslan Akc¸a (born 1936) studied forestry at the University of Istanbul,
Turkey and at the University of Freiburg, Germany. He received his doctorate
in forestry at the University of Freiburg on identification of land use classes
and forest types by means of microdensitometer and discriminant analyses in
1970, for his habilitations in photogrammetry and geodesy at the University
of Istanbul in 1976, and in forest inventory and forest management at the
University of Go¨ttingen in 1981. He was Professor for Forest Management,
ForestInventory,andRemoteSensingattheUniversityofGo¨ttingen.Heretired
in 2001. His main research interest is in forest mensuration, forest inventory,
andremotesensinginforestry.
PREFACE
Forest mensuration is one of the most fundamental disciplines within forest
and related sciences. It deals with the measurement of trees and stands and
the analysis of the resultant information. During the early days of sustained
forest management simple measurement and estimation methods and with the
analysisofinventoryandresearchdatawereavailable.Themiddleoflastcen-
tury, however, witnessed a worldwide increase in the need for more quanti-
tative information about trees and stands. This generated the need for more
sophisticatedmethodstoobtainandanalyzeforestdata.Thisdevelopmentwas
followedbyaphenomenalexplosionofinformation.
During the past decades there has been fruitful cooperation between the
Institute of Forest Inventory and Forest Growth, formerly “Institute of Forest
Management and Forest Yield Sciences” of the University of Go¨ttingen,
Germany and the Faculty of Forestry of the University of Stellenbosch, South
Africa.Thisbookisoneoftheresultsofthisfruitfulcooperationbetweenthese
institutions.
The first edition of this book was published in 1997 by Cuvilliers in
Go¨ttingen. It was completely revised and supplemented with a presentation
and review of recently developed tools and methods to measure and analyze
forestry-relateddata.Thepurposeofthisbookistoprovideinformationabout
the subject for those readers who are involved in this category of quantitative
methods.Sincethemiddleoflastcenturytheincreasedavailabilityofpersonal
computers, and software and the consensus that statistical methods are indis-
pensable for estimating tree and stand parameters and for testing statistical
hypotheses,hadaconsiderableimpactontheprogressofforestmensurationas
aresearchandmanagementtool.
vii
viii Preface
Ithasbeenwrittenforforestrystudentsandforpracticalforesters,anddoes
not presuppose a more than elementary knowledge of mathematics and statis-
tics. However, because of the notable influence of statistics on forest mensu-
ration methods and techniques, and the crucial role of sampling techniques,
it reviews and evaluates elementary statistical concepts. At the same time it
was thought to be imperative to discuss spatial structure and diversity and to
addachapteronconventionalanddigitalremotesensing.Numerouspractical
examples have been included in this edition. They are thought to be particul-
arly useful for university and college students. Additional information about
specific topics has been added for the benefit of the advanced reader and was
writteninitalics.
ForestmensurationasascientifictooloriginatedinEuropeandhasalways
played an important role in the practice of forest management. In addition
to conventional terrestrial methods, quantitative remote-sensing techniques
form an integral part of the forest mensuration curriculum at the University
of Go¨ttingen. Countries in the southern hemisphere can derive considerable
benefits from this longtime experience. Conversely, short-rotation plantation
forestryinthesouthernhemisphereandmoreparticularlyinSouthAfricaacted
asastimulusfortheapplicationofstatisticsandotherquantitativemethodsas
adecision-makingtool.
The Authors are greatly indebted to Mrs. J. Wirkner for proofreading the
Englishtextofthefirstedition,Mrs.S.Ru¨digerforthetechnicaldrawingsand
graphs,andMr.W.Tambourforhisillustrations.Wewouldfurthermoreliketo
sincerelythankMr.Th.BeischandMr.H.Heydeckefortheirconstantsupport
in electronic data-processing matters, as well as Mrs. F.J.A. Allwright, who
assistedwiththecorrespondenceandEDPinStellenbosch.
The authors gratefully acknowledge the inclusion of research data from
various sources, more particularly from the Faculties of Forestry at the
Universities of Go¨ttingen and Stellenbosch respectively and those obtained
fromProfessorProdaninFreiburgandDr.ForrestinAustraliacouldbeincor-
porated into the current edition. They gratefully acknowledge permission
from Professor Dr. H.C.H. Kramer and Professor Dr. A. Akca, the authors of
“Waldmesskunde,” to include numerous drawings from this book. And finally
oursincerethanksareduetoSpringerandEditorsofthebookserieswhomade
thepublicationofthiseditionpossible.
AnthonievanLaar
Stellenbosch,SouthAfrica
AlparslanAkc¸a
Go¨ttingen,Germany
May2007
SUMMARY
The management of forests and tree plantations requires a quantitative esti-
mateofthecurrentandfuturevolumeandbiomassoftimberandby-products,
at national, regional, and local levels. Such information is also needed for
forest-policy decisions. Forest and forestry research requires a great deal of
additional information, for example about the density of forests and stands,
diversity, spatial distribution of trees within stands, the size and size distribu-
tion of trees within stands, and the expected growth of trees and stands. For-
est mensuration is the discipline which deals with these topics. During recent
years,considerableprogresshasbeenmadetodevelopmethodsformeasuring
tree and stand characteristics, but also in instrumentation and in the statistical
analysis of forest mensurational information. Sampling, based on inferential
statistics,playsadominantroleinforestmensurationandforestinventory,pri-
marily because of the high cost of collecting and processing field data. Mod-
ern sampling methods make it possible to find an optimum sampling strategy
whichproducessufficientlyaccurateestimatesatthelowestcost.Quantitative
information is primarily obtained by ground surveys, aerial photographs, and
satelliteimageryareincreasinglyappliedtoobtainbasicinformationaboutthe
spatial distribution of forests, possibly also to classify these forests according
tospecifiedcategoriesandtosupplementgroundsurveys.
Inthisbooktheauthors,whoareemeritusprofessorsattheUniversitiesof
StellenboschandGo¨ttingeninSouthAfricaandGermanyrespectively,summa-
rizeandreviewcurrentlyusedforestmensurationandforestinventorymethods.
Alargenumberofworkedexampleshavebeenadded,primarilyforthebenefit
ofundergraduateandpostgraduatestudents.
ix
CONTENTS
PREFACE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . vii
SUMMARY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ix
Chapter1: INTRODUCTION . . . . . . . . . . . . . . . . . . . . 1
Chapter2: STATISTICALPREREQUISITES . . . . . . . . . . . 5
1 INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . 5
2 SCALESANDUNITSOFMEASUREMENT . . . . . . . . 6
2.1 Scalesofmeasurement . . . . . . . . . . . . . . . . . 6
2.2 Unitsofmeasurement . . . . . . . . . . . . . . . . . 7
3 GRAPHICALPRESENTATIONOFDATA . . . . . . . . . . 7
4 DESCRIPTIVESTATISTICS . . . . . . . . . . . . . . . . . 9
5 PROBABILITYDISTRIBUTIONS . . . . . . . . . . . . . . 13
5.1 Normaldistribution . . . . . . . . . . . . . . . . . . . 13
5.2 Binomialdistribution . . . . . . . . . . . . . . . . . . 15
5.3 Poissondistribution . . . . . . . . . . . . . . . . . . . 16
5.4 Distributionofχ2 . . . . . . . . . . . . . . . . . . . 17
5.5 Distributionofstudent’st . . . . . . . . . . . . . . . 18
6 ESTIMATION . . . . . . . . . . . . . . . . . . . . . . . . . 20
6.1 Bias,precisionandaccuracy . . . . . . . . . . . . . . 20
6.2 Estimators . . . . . . . . . . . . . . . . . . . . . . . 22
6.3 Estimatingaccuracy . . . . . . . . . . . . . . . . . . 23
7 REGRESSIONANDCORRELATIONANALYSIS . . . . . . 25
7.1 Simplelinearregression . . . . . . . . . . . . . . . . 25
7.2 Correlationanalysis . . . . . . . . . . . . . . . . . . 26
7.3 Multipleregressionanalysis . . . . . . . . . . . . . . 26
7.4 Nonlinearregression . . . . . . . . . . . . . . . . . . 27
8 MOVINGAVERAGE . . . . . . . . . . . . . . . . . . . . . 27
xi