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THE FORESTS HANDBOOKVolume 1
EDITORIAL ADVISERS
D.C. MALCOLMInstitute of Ecology and Resource Management
University of Edinburgh,Edinburgh, United Kingdom
L.A. MORRISDaniel B. Warnell School of Forest Resources,
University of Georgia,Athens, United States of America
EDITORIAL ASSISTANTS
Claire Holmes (Forest Research, UK)
Delia Sandford (Blackwell Science Ltd)
The Forests HandbookVOLUME 1
AN OVERVIEW OF
FOREST SCIENCE
EDITED BY
JULIAN EVANS OBE BSc, PhD, DSc, FICFor
T.H. Huxley School of Environment, Earth Sciences and Engineering,Imperial College of Science, Technology and Medicine, The University of London
© 2001 byBlackwell Science LtdEditorial Offices:Osney Mead, Oxford OX2 0EL25 John Street, London WC1N 2BS23 Ainslie Place, Edinburgh EH3 6AJ350 Main Street, Malden
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First published 2001
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A catalogue record for this titleis available from the British Library
ISBN 0-632-04821-2 (vol. 1)0-632-04823-9 (vol. 2)0-632-04818-2 (set)
Library of CongressCataloging-in-Publication Data
The forests handbook/edited byJulian Evans.
p. cm.Includes bibliographical
references.Contents: v. 1. An overview of
forest science.ISBN 0-632-04821-21. Forests and forestry.
I. Julian Evans.SD373 .F65 2000333.75 —dc21 00-021516
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Contents
2.3.4 Dominant forest types, 312.3.5 Regional formations, 31
2.4 Temperate broadleaf and coniferous forests, 372.4.1 Distribution and extent, 372.4.2 Climate, 382.4.3 Soils, 382.4.4 Regional formations, 38
2.5 Savannahs and open woodland, 532.5.1 Distribution and extent, 542.5.2 Climate, 542.5.3 Soils, 542.5.4 Regional floras, 55
2.6 Mediterranean ecosystems, 572.6.1 Distribution and extent, 582.6.2 Climate, 582.6.3 Soils, 582.6.4 Regional floras, 58
2.7 Summary, 60
Part 2: Biological and Ecological Processes
3 Genetics and Speciation in the World’s Forests, 67Gene Namkoong and Mathew P. Koshy3.1 Introduction, 673.2 The wealth of forest tree species, 68
3.2.1 Cladogenesis, 693.2.2 Selection, 713.2.3 Migration, 723.2.4 Chromosomal change, 733.2.5 Hybridization, 74
3.3 The wealth of populations, 753.4 The wealth of intrapopulation genetic
variation, 783.5 Conclusions, 80
List of contributors, x
Preface, xii
Acknowledgements, xiv
VOLUME 1
Part 1: Forest Resources and Types
1 Global Forest Resources: History and Dynamics, 3Jim B. Ball1.1 Historical perspective, 31.2 Recent estimates of global forest area, 6
1.2.1 Natural forests, 81.2.2 Forest plantations, 9
1.3 Changes in forest cover and condition, 141.3.1 Changes in forest cover, 141.3.2 Conversion of forests to other land
cover, 151.3.3 Changes in forest condition, 18
1.4 Conclusions, 20
2 Forest Types and Classification, 23Ronald L. Hendrick2.1 Introduction, 232.2 Boreal forests, 23
2.2.1 Distribution and extent, 242.2.2 Climate, 242.2.3 Soils, 252.2.4 Dominant forest types, 252.2.5 Regional floras, 26
2.3 Tropical and subtropical forests, 292.3.1 Distribution and extent, 292.3.2 Climate, 302.3.3 Soils, 30
v
vi Contents
4 Structural Dynamics of Forest Stands and Natural Processes, 83George F. Peterken4.1 What counts as disturbance?, 834.2 Sources of disturbance, 84
4.2.1 Wind, 844.2.2 Fire, 854.2.3 Drought, 864.2.4 Biotic, 864.2.5 Water, 874.2.6 Ice, 874.2.7 Topography and landform, 87
4.3 Disturbance regimes, 884.4 Tree and shrub responses, 894.5 Forest structure and patterns, 914.6 Dead wood, 934.7 Dynamic pattern of forest composition, 94
4.7.1 Highly disturbed environments, 944.7.2 Relatively undisturbed environments,
954.7.3 Interactions and intermediate
conditions, 964.7.4 Influence of people, 97
4.8 Stability, succession and climax, 984.9 People as agents of disturbance, 99
4.9.1 Seminatural disturbances, 994.9.2 Silvicultural systems, 994.9.3 Traditional cultures as part of nature,
101
5 Biological Interactions and Disturbance: Plants and Animals, 105Jaboury Ghazoul and Eunice A. Simmons5.1 Introduction, 1055.2 Diversity and distribution of forest vertebrate
resources, 1065.2.1 Habitat structure and some generalities
of vertebrate responses to resource variability, 106
5.2.2 Issues of scale, 1075.3 Vertebrate richness and diversity in primary
and disturbed forests, 1085.3.1 Birds, 1105.3.2 Mammals, 1115.3.3 Amphibians, 1115.3.4 Reptiles, 112
5.4 Vertebrate-mediated ecological processes and impacts of disturbance, 112
5.4.1 Pollination, 1135.4.2 Seed predation, 1145.4.3 Seed dispersal, 1155.4.4 Herbivory, 117
5.5 Vertebrate invaders as mediators of change, 118
5.6 Economic value, hunting and tourism, 1185.7 Conclusions, 120
6 Biological Interactions and Disturbance: Invertebrates, 128Hugh F. Evans6.1 Description of processes or characteristics,
1286.1.1 Ecological attributes that determine
the diversity and abundance of invertebrate species in forest ecosystems, 128
6.1.2 Geographical isolation as a critical factor in determining invertebrate diversity and implications for international movement of pest organisms, 132
6.2 Principles and dynamics that govern events and occurrence, 1336.2.1 Interactions with the food plant:
phytophagous invertebrates (herbivores), 134
6.2.2 Interactions between herbivores and their natural enemies, 136
6.3 Interactions with other processes, with scale and with forest type, 141
6.4 Factors influencing processes and opportunities for manipulation, 1436.4.1 Forest fragmentation at local and
landscape scales, 1456.4.2 Forest disturbance as a factor in
invertebrate dynamics, 1466.5 Understanding the forest as a basis for
management, 147
Part 3: Environmental Interactions
7 Forest Soils, 157Peter M. Attiwill and Christopher J. Weston7.1 Introduction, 157
7.1.1 Scope of this chapter, 1577.2 Nutrient cycling in forests, 158
Contents vii
7.2.1 Soil chemistry and nutrient cycling, 158
7.2.2 Roots and the rhizosphere, 1627.3 Litter and soil organic matter, 164
7.3.1 Litter and litter decomposition, 1647.3.2 Carbon in forest soils, 166
7.4 Forest soils and acidic inputs, 1707.4.1 Forest decline, 1707.4.2 Nitrogen saturation, 172
7.5 Timber harvesting and sustainability, 1737.5.1 Timber harvesting, nutrient removal
and sustained productivity, 1737.5.2 Timber harvesting, soil compaction and
sustainability, 179
8 Ecophysiology of Forests, 188Richard H. Waring and Anthony R. Ludlow8.1 Introduction, 1888.2 Responses of forests to variation in climate,
1888.2.1 Determination of temperature
optimum and limits, 1898.2.2 Physiological definition of soil drought,
1898.2.3 Sapwood as a water reservoir in trees,
1908.2.4 Transpiration by forests, 191
8.3 Responses of forests to variation in nutrient availability, 1928.3.1 Optimum nutrition, 1928.3.2 Internal recycling of nutrients, 193
8.4 Carbon balance analyses, 1938.4.1 Canopy photosynthesis, 1948.4.2 Autotrophic respiration, 1958.4.3 Net primary production, 1968.4.4 Allocation of carbon resources, 197
8.5 Susceptibility of forests to herbivores and pathogens, 1998.5.1 Biochemical and structural defences,
1998.5.2 Biochemical and allocation ratios, 200
8.6 Ecophysiological models of forest growth, 2028.7 Summary, 204
9 Models for Pure and Mixed Forests, 210Hans Pretzsch9.1 Introduction, 210
9.2 Patterns and dynamics of growth: empirical observations, 2109.2.1 Periodicity and pattern in individual
tree growth, 2109.2.2 Dynamics of stand growth, 2119.2.3 Interventions and manipulations, 212
9.3 Growth models, 2129.3.1 Stand growth models based on mean
stand variables, 2149.3.2 Stand-orientated management models
predicting stem number frequency, 2159.3.3 Single-tree orientated management
models, 2179.3.4 Ecophysiological growth models, 2199.3.5 Gap models and biome shift models,
2219.3.6 Hybrid models for forest management,
2229.3.7 Management model SILVA 2.2 for pure
and mixed stands, 222
10 Forests and the Atmosphere, 229Paul G. Jarvis and David G. Fowler10.1 Introduction, 229
10.1.1 Spatial and temporal scales, 22910.1.2 Historical development, 23110.1.3 The stand system, 232
10.2 Stand energy balance, 23210.3 Radiation exchange, 234
10.3.1 Solar radiation albedo, 23410.3.2 Long-wave radiation exchange, 23510.3.3 Net all-wave radiation balance, 235
10.4 Momentum exchange, 23610.5 Exchange of scalars, 236
10.5.1 Aerodynamic conductance/resistance, 238
10.5.2 Surface conductance/resistance, 239
10.6 Evaporation and transpiration, 23910.6.1 Driving variables and constraints,
23910.6.2 Evaporation of intercepted water,
24010.6.3 Evaporation of transpired water,
24110.6.4 Some conclusions, 244
10.7 Carbon dioxide exchange, 24410.7.1 The policy imperative, 24410.7.2 Forests as a carbon pump, 245
viii Contents
10.7.3 Dynamics of carbon dioxide exchange, 246
10.7.4 Net transfer of carbon dioxide from the atmosphere to forests, 248
10.7.5 Carbon balance components, 25110.7.6 Future carbon sequestration
potential, 25210.8 Trace gases, aerosols and cloud droplets,
25510.8.1 Acid gases: HCl, HNO3, HF, 25510.8.2 Ammonia, 25710.8.3 Sulphur dioxide, 26110.8.4 Nitric oxide and nitrogen dioxide,
26210.8.5 Ozone, 26410.8.6 Aerosols and cloud droplets, 26610.8.7 Diurnal and seasonal cycles, 268
10.9 Ecological effects of nitrogen deposition, 26910.9.1 Nitrogen-stimulated carbon
sequestration, 27110.10 Forests and regional climates, 27210.11 Conclusions, 273
11 Environmental Stresses to Forests, 282Peter H. Freer-Smith11.1 Introduction, 28211.2 Climate, 28311.3 Pollution, 287
11.3.1 Direct effects, 28811.3.2 Indirect effects and soil acidification,
28811.3.3 Atmospheric concentrations of
carbon dioxide, 29311.3.4 Nitrogen depositions, 294
11.4 Water deficit, 29511.5 Soil conditions, nutrient deficiency/
enrichment and soil degradation, 29611.6 Conclusions, 298
12 Forest Hydrology, 301L.A. (Sampurno) Bruijnzeel12.1 Introduction, 30112.2 Forest hydrological cycle, 30212.3 Forests and ‘occult’ precipitation, 30412.4 Throughfall, stemflow and interception loss,
306
12.4.1 Amounts and measurement of rainfall interception, 306
12.4.2 Litter interception, 30912.4.3 Interception modelling, 309
12.5 Transpiration, 31412.5.1 Amounts and measurement of
transpiration, 31412.5.2 Transpiration modelling, 318
12.6 Total evapotranspiration, 31912.7 Hydrological effects of forest manipulation,
32112.7.1 Effects of forest thinning on rainfall
interception, 32112.7.2 Effects of thinning and selective
logging on transpiration and water yield, 322
12.7.3 Effect of forest clearfelling on water yield, 324
12.7.4 Effects of converting natural forest to other land cover types on water yield, 328
12.7.5 Effects of forest clearing on streamflow regimes, 329
12.7.6 Hydrological effects of (re)forestation, 330
12.7.7 Modelling the hydrological impacts of forest manipulation and land-use change, 332
12.8 Outlook, 333
Part 4: Social and Human Interface
13 Trees in the Urban Environment, 347Kjell Nilsson, Thomas B. Randrup and Barbara M. Wandall13.1 Introduction, 34713.2 Definitions, 34713.3 Urban growing conditions, 348
13.3.1 Stress factors, 34913.3.2 Characteristics and restriction of
rooting in the built environment, 350
13.4 Urban characteristics/environment analysed, 350
13.5 Amenity values/benefits of urban forests and trees, 35113.5.1 Economic impact, 351
Contents ix
13.5.2 Recreational use of green areas, 351
13.5.3 Psychological aspects, 35213.5.4 Environmental education, 35213.5.5 Community involvement, 353
13.6 Environmental aspects, 35313.6.1 Local-scale climate, 35313.6.2 Air quality, 35413.6.3 Biodiversity, 35413.6.4 Sustainable urban forests, 355
13.7 Threats to green areas, 35513.7.1 Urbanization pressure, 35513.7.2 Social factors, 35613.7.3 Economic cuts, 356
13.8 Planning and management of urban green areas, 35613.8.1 Green infrastructure planning,
35713.8.2 Conflicts in management, 358
13.9 Conclusions, 358
14 The Importance of Social Values, 362Stephen Bass14.1 Sustainable forest management involves
political and social processes, 36214.2 Forests provide multiple social values, 36314.3 The challenge of achieving security of forest
values, 36614.4 People’s means to achieve security of forest
values, 36714.4.1 Traditional knowledge, 36714.4.2 Rights, 368
14.5 Reasons for nurturing social values in commercial forest management, 369
14.6 Codes of practice and certification standards on social issues, 369
14.7 Conclusions, 370
15 Non-timber Forest Products and Rural Poverty: an Economic Analysis, 372William Cavendish15.1 Why non-timber forest products and rural
poverty?, 37215.2 Economic characteristics of rural
households, 37415.3 Value of NTFPs to rural households and the
causes of NTFP use, 37615.3.1 Evidence on rural households’ use of
NTFPs, 37615.3.2 Economic underpinnings of rural
households’ extensive use of NTFPs, 381
15.4 Can rural development be based around NTFPs?, 38315.4.1 The problem of preferences, 38315.4.2 High transactions costs of trading,
38515.4.3 Storage problems, 38615.4.4 Production risk, 38615.4.5 Open access and the costs of
privatization, 38615.4.6 Incentives for domestication and
technical substitution, 38715.5 Conclusions, 388
Synthesis and conclusions, 392
Index, 394
Colour plate section appears between pp. 306 and 307
List of Contributors(Volume 1)
PETER H. FREER-SMITH ForestResearch, Alice Holt Lodge, Wrecclesham,Farnham, Surrey GU10 4LH, [email protected]
JABOURY GHAZOUL T.H. Huxley Schoolof Environment, Earth Sciences and Engineering,Imperial College, Silwood Park, Ascot, BerkshireSL5 7PY, [email protected]
RONALD L. HENDRICK Daniel B.Warnell School of Forest Resources, University ofGeorgia, Athens, Georgia 30602 [email protected]
PAUL G. JARVIS Institute of Ecology andResource Management, Darwin Building,University of Edinburgh, Mayfield Road,Edinburgh EH9 3JU, [email protected]
MATHEW P. KOSHY Department of ForestSciences, Faculty of Forestry, 3041-2424 MainMall, University of British Columbia, Vancouver,British Columbia, Canada V6T 1Z4
ANTHONY R. LUDLOW 7 Kings Road,Alton, Hamshire GU34 1PZ, [email protected]
GENE NAMKOONG Department of ForestSciences, Faculty of Forestry, 3041-2424 MainMall, University of British Columbia, Vancouver,British Columbia, Canada V6T [email protected]
PETER M. ATTIWILL School of Botany,University of Melbourne, Parkville, Victoria3052, [email protected]
JIM B. BALL Coordinator, Forest ProgrammesCoordination and Information Unit, ForestryDepartment, UN Food and AgricultureOrganization, Rome, [email protected]
STEPHEN BASS International Institute forEnvironment and Development, 3 EndsleighStreet, London WC1H 0DD, [email protected]
L.A. (SAMPURNO) BRUIJNZEELFaculty of Earth Sciences, Vrije Universiteit, De Boelelaan 1085, 1081 HV Amsterdam, [email protected]
WILLIAM CAVENDISH Head of Policy, The Labour Party, MillbankTower, Millbank, London SW1P 4GT, [email protected]
HUGH F. EVANS Forest Research, Alice Holt Lodge, Wrecclesham, Farnham, Surrey GU104LH, [email protected]
DAVID G. FOWLER Centre for Ecology andHydrology, Edinburgh Research Station, BushEstate, Penicuik, EH26 0QB, [email protected]
x
List of contributors xi
KJELL NILSSON Danish Forest andLandscape Research Institute, HorsholmKongevej 11, 2970 Horsolm, [email protected]
GEORGE F. PETERKEN BeechwoodHouse, St Briavels Common, Lydney,Gloucestershire GL15 6SL, [email protected]
HANS PRETZSCH Chair of Forest YieldScience, University of Munich, Am Hochanper13, 85354 Friesing, [email protected]
THOMAS B. RANDRUP Danish Forestand Landscape Research Institute, HorsholmKongevej 11, 2970 Horsholm, [email protected]
EUNICE A. SIMMONS EnvironmentDepartment, Wye College, University of London,Wye, Kent, TN25 5AH, [email protected]
BARBARA M. WANDALL Danish Forestand Landscape Research Institute, HorsholmKongevej 11, 2970 Horsholm, [email protected]
RICHARD H. WARING College ofForestry, Oregon State University, Corvallis,Oregon, OR97331 [email protected]
CHRISTOPHER J. WESTON School ofForestry, The University of Melbourne, Creswick,Victoria 3363, [email protected]
Preface
topics written by highly competent authorities.To achieve this authors were given considerablelatitude to interpret their topic. In effect,although chapters are linked logically they do notnecessarily trace a coherent flowing story, but aremore a suite of essays that move through theirsubjects as the authors have chosen to addressthem. The value of this approach is to allowdevelopment of topics and themes by those bestplaced to write about them in ways that arelargely unfettered.
While it is impossible to claim worldwide coverage, there is a deliberate attempt to make the text relevant across the globe and todraw on examples, cite practices and relate experience from a great many countries. Omis-sions are largely what might be termed ‘forestry’such as forest economics, forest logging and har-vesting operations, the whole matter of utiliza-tion and trade in forest products, and there is onlylimited coverage of forest fires and the pressingproblem of tropical deforestation per se. There isinsufficient treatment of social and policy-relatedfactors in forest development. And, of course, notall the riches in the world’s forest types can bementioned. Indeed, apart from Chapter 2 inVolume 1, authors do not treat their subjects bytaxonomic groupings but take a more functionalapproach. In contrast to perceived omissions,several chapters deal with aspects of ecophysiol-ogy and forest–environment interaction and some three chapters address the importantsubject of forest soils and/or their management.Foresters and forest scientists are notorious forneglecting this aspect of the ecosystem and theemphasis on soil is deliberate and welcome evenif in a few places there is some repetition as the
The Forests Handbook joins an eminent series ofBlackwell’s ‘Handbooks’. However, the connota-tion of ‘Handbook’, for those brought up in theEnglish tradition, is that of a practical manualtelling the reader how to do things. This ‘hand-book’ is not like that at all. What we have done inthese two volumes is to assemble a unique com-pilation, and I employ that overused adjectiveadvisedly. It is unique in the sense of bringingtogether eminent foresters, biologists, ecologists,scientists, academics and managers from manycountries to tell a story that embraces much ofthe span of what we call ‘forest science’ thoughnot all of operational forestry.
Volume 1 seeks to present an overview of theworld’s forests from what we know about wherethey occur and what they are like, about the waythey function as complex ecosystems, as ‘organ-isms’ interacting with their environment, andabout their interface with people —at least in part.We have tried to present the state-of-the-artscience, and to present it in a way accessible tothe general reader with an interest in trees, forestsand forestry. It is, after all, sound science thatunderpins sustainable forest management.
Volume 2 seeks to apply this science to goodpractice. It is focused on operations and theirimpacts, on principles governing how to protectforests and on how to harness in sustainable waysthe enormous benefits forests confer in additionto supply of wood. Volume 2 also contains valu-able and highly informative case studies drawnfrom several countries to illustrate key points andshow good management in practice.
In only two volumes one cannot cover every-thing, nor everything in detail and in depth. Whatis presented is a series of overviews of interrelated
xii
Preface xiii
different authors provide their own perspectives.We recognize all these imbalances and ask forreaders’ forbearance. While coverage may not becomprehensive, we hope anyone interested in theworld’s forests will find much here to welcome.We hope, too, that it helps forward the goal of sus-tainable forest management
But why have a Forests Handbook? We believe
that nowhere else will such a broad sweep ofmodern forest science and its application be foundin two books, and in two books that bringtogether 45 authors from 12 countries to presenttheir own perspectives. It was a monumentaltask, but worth it.
Julian EvansApril 2000
Acknowledgements
I must also thank Claire Holmes of ForestResearch (UK) and Delia Sandford of BlackwellScience who successively fulfilled that crucialrole of editorial assistant. Their persistence inchasing up authors and keeping a check on thissizable undertaking was enormously appreciated.Added to this, Blackwell Science’s editors weresupportive throughout: Susan Sternberg and sub-sequently Delia herself.
I would also like thank Gus Hellier, who helped with chapter formatting and under-took the tedious task of checking references forme.
Finally, I am grateful to Imperial College ofScience, Technology and Medicine for enablingme to continue this project during the two yearssince joining their staff.
I am greatly indebted to Douglas Malcolm andLarry Morris for taking on the role of editorialadvisers. Not only did they guide development ofthe book itself but in many instances undertookthe arduous task of refereeing chapters. Thanksexpressed here cannot do justice to the signifi-cance of their contribution to The Forests Hand-book. That said, I must accept responsibilities forany mistakes, inaccuracies or omissions in thetext.
A book of this type is primarily judged by thequality and diligence of its many authors, not ofthe editor. I am full of admiration for what theauthors collectively have achieved and I recordmy thanks without reservation for all their hardwork and dedication. We even kept close to theset deadlines!
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