Forests, Water and People in the Humid Tropics: Past, Present and Future Hydrological Research for Integrated Land and Water Management (International Hydrology Series)

Cover......Page 1
Half-title......Page 3
Series-title......Page 4
Title......Page 5
Copyright......Page 6
Contents......Page 7
Contributors......Page 10
Foreword......Page 13
Preface......Page 15
Acknowledgements......Page 17
Symposium and Workshop......Page 18
Introduction......Page 21
Part I: Current trends and perspectives on people–land use–water issues......Page 25
Introduction......Page 29
Observing land cover, inferring land use......Page 30
Country statistics of forest cover......Page 31
Hot spots of tropical deforestation as defined by the TREES  project......Page 33
Pan-tropical land cover monitoring (remote sensing component, RSS, of the FAO Forest Resources Assessments of 1990 and 2000)......Page 34
Processes of land cover change and their trends at the pan-tropical, regional and eco-regional level......Page 36
Regional character of processes governing land cover change......Page 40
Eco-regional distribution of forest change......Page 48
Main results of the trees ii survey of deforestation in the humid tropics......Page 50
Concluding remarks......Page 52
Trends......Page 53
appendix 1.1 monitoring tropical land cover change: key methodological features......Page 54
appendix 1.2 definitions of forest and forest change......Page 56
appendix 1.3 examples of local land cover change processes......Page 57
appendix 1.4 pan-tropical woody biomass flux diagram 1990–2000: main transition types and causes of forest depletion......Page 58
The concept of efficiency......Page 60
Methods......Page 61
Agricultural analysis......Page 62
Energy use and economic activity......Page 63
Agricultural efficiency......Page 67
Discussion and conclusions......Page 73
The failure of development based on neoclassical economics to provide useful guidelines......Page 75
Neoclassical economics as an excuse for plunder......Page 76
the resource managers and external factors influencing them......Page 79
Government......Page 82
Private sector......Page 83
Conclusions......Page 84
Forces of change......Page 86
other groups of forest-dependent peoples......Page 87
Who should control the forest?......Page 88
Forest dweller effects on hydrology......Page 89
Water in the lives of forest dwellers......Page 90
Potential roles for forest people......Page 91
Strategies for engaging people and communities......Page 92
Conclusions......Page 93
5 People in tropical forests: problem or solution?......Page 95
Forest peoples as a solution......Page 97
Self-defence and vigilance......Page 98
resource management and capacity-building......Page 99
Policy dialogue......Page 101
Conclusion......Page 102
Governance mechanisms......Page 103
Introduction......Page 106
A quarter-century of debate......Page 107
The scientific viewpoint......Page 108
El Cajón in Honduras......Page 110
The Lempa River in El Salvador......Page 111
The Panama Canal......Page 113
Hurricane Mitch......Page 115
Conclusions......Page 116
Introduction......Page 119
Hydrological impacts of land use change......Page 120
Land use change, hydrology and economic welfare......Page 121
Hydrological outputs as inputs to the household production......Page 122
Downstream economic impacts of changes in hydrological function......Page 123
Valuation of water quality impacts......Page 124
Valuation of water quantity impacts......Page 127
The direction of hydrological externalities......Page 133
Conclusions......Page 135
Introduction......Page 141
Land use planning and watershed management......Page 142
Regional scale......Page 143
National scale......Page 145
Local scale......Page 147
Policy responses......Page 149
Concluding remarks......Page 152
Decentralisation and potential for local environmental management and policy......Page 154
A participatory research approach......Page 155
Indicator 1: Community perceptions, memories and experience......Page 159
Indicator 2: Soil erosion and suspended solids......Page 160
Indicator 3: Altered streamflows......Page 161
Indicator 4: Sediment yield......Page 162
From indicators to policy......Page 163
Other effects on policy......Page 165
Factors for successful use of indicators in policy......Page 166
Future needs and applications of indicators......Page 167
Lessons learned......Page 168
Part II: Hydrological processes in undisturbed forests......Page 171
Low-level circulation......Page 178
Features of the upper atmospheric circulation......Page 182
The Indian monsoon......Page 186
Monsoon depressions......Page 187
The Asian–Australian monsoon......Page 188
The West African monsoon......Page 189
South Atlantic Convergence Zone (SACZ)......Page 190
Kelvin waves......Page 194
Madden–Julian oscillation (MJO)......Page 195
The El Niño/Southern Oscillation (ENSO) in Australia......Page 197
Northwest Pacific–Asia......Page 198
Indian rainfall......Page 199
Equatorial westerly gales......Page 200
Kelvin waves and El Niño......Page 201
West African interdecadal variability......Page 204
Indian monsoon......Page 206
Longer-term variations......Page 207
Conclusions......Page 208
Appendix 10.1 glossary of terms used in this chapter and the following chapter......Page 209
Introduction......Page 214
Current debate on the mechanisms connected with the formation and intensification of tropical cyclones......Page 215
Rapid intensification of tropical cyclones adjacent to the east coasts of continents......Page 216
Summary of the characteristics of rapid intensification......Page 217
Extreme tropical cyclone rainfall events......Page 218
The rain structure of tropical cyclones and depressions......Page 220
Common synoptic patterns between the south west Pacific and south west Indian Ocean during record rainfall events (northeast Queensland and La Réunion Island)......Page 221
Comparison of two severe tropical cyclones in Fiji of contrasting vertical wind and rain structure......Page 223
The synoptic meteorological controls of Hurricane Mitch: an example of a slow moving system which produced high rainfalls......Page 224
Climatological aspects of tropical cyclones linked with rainfall......Page 226
Perturbations in the easterlies......Page 227
A climatological reassessment of African easterly perturbations, 1979–1998......Page 230
The possible links between topographic relief and the genesis of African easterly perturbations......Page 233
Precipitation in tropical easterly perturbations: a case study over the Lesser Antilles archipelago (Guadeloupe)......Page 234
The first ever recorded tropical cyclone in the South Atlantic......Page 235
North Atlantic patterns for tropical cyclogenesis from troughs in the easterlies......Page 238
Definitions and theoretical considerations......Page 239
The structure of MCSs......Page 242
Example of a severe MCS near Fiji 18–20 January 1999......Page 245
South America......Page 246
Middle America and the Caribbean......Page 251
The oceans adjacent to Central and South America......Page 252
An example of the diurnal evolution of tropical island convection within the maritime continent......Page 253
MCSs over the TOGA area......Page 254
The diurnal cycle of surface rainfall in TOGA–COARE over the ocean......Page 259
Trade wind layer depth and moisture......Page 260
Perturbations in trade wind flow at the mesoscale......Page 261
Aspects of tropical rainfall: intensity–frequency–duration, and more on topographic interactions......Page 262
Rainfall intensity–frequency–duration......Page 263
Extreme rainfalls linked with topographic interactions......Page 266
Overview of methodologies......Page 269
Selected studies......Page 270
A classification of global tropical rainfall stations......Page 271
Precipitation recycling......Page 278
Effect of surface heterogeneity of land cover......Page 279
Conclusions......Page 281
Appendix 11.1......Page 282
Reconstructing past climates......Page 287
The historical and climatic framework of African tropical forests from the end of the Tertiary period to the Quaternary period......Page 288
The maximum forest extension during the Holocene: The chronological lag between the African and the Amazonian rainforests......Page 290
Earth radiation budget (ERB)......Page 292
The role of water and the involvement of the tropical forest in the water cycle......Page 293
Evaluating the climatic impact of forest conversion: modelling global terrestrial vegetation–climate interactions......Page 295
Climatic variability and impact on rainfall and runoff in West and Central Africa......Page 297
Interannual and multiannual scale: the Southern Oscillation......Page 299
An approximate ten-year cycle: the tropical Atlantic......Page 300
Recent fluctuations in climate: the trend towards increasing temperatures and decreasing rainfall over West Africa......Page 301
Conclusions......Page 303
Introduction......Page 307
Hydrological studies in tropical rainforests......Page 308
The control of transpiration at the leaf level......Page 309
The control of forest transpiration at the stand level......Page 312
Measuring rainfall interception in tropical rainforest......Page 320
Modelling rainforest rainfall interception......Page 323
Interception from maritime sites......Page 324
Future research needs in lowland tropical rainforests......Page 325
Appendix 13.1 list of symbols......Page 329
Introduction......Page 334
Rainfall......Page 335
The limitations of point measurements and in situ parameterisation of soil and rock properties linked with hillslope hydrology......Page 336
Comparative studies of hillslope hydrology in the humid tropics......Page 338
Predominantly vertical pathways......Page 342
Predominantly lateral pathways......Page 351
The impact of complex geology and soils on dominant stormflow pathways......Page 396
A conceptual framework of hillslope hydrology responses linked with tropical rainforest soil landscapes......Page 402
The role of riparian zones in the runoff generation process......Page 404
Digital terrain models for runoff simulation......Page 405
The role of \'DEEP\' groundwater......Page 414
A controversial issue: does stormflow increase and delayed flow decrease following forest conversion?......Page 415
Achievements and research gaps......Page 417
Influence of rainfall......Page 427
Patterns of sediment yield in large basins and throughout the humid tropics......Page 429
Erosion processes in small catchments......Page 432
Overland flow, subsurface flow, channel head dynamics and sediment supply......Page 434
Landsliding and mass movements......Page 435
Regulation of sediment discharge by coarse woody debris......Page 436
Variation in storm period-sediment yield with antecedent conditions......Page 438
Appendix 15.1 characteristics of the world‘s eight largest tropical rivers......Page 439
The rainforest nutrient cycle......Page 442
Quantification of pools and fluxes......Page 443
Soil analyses......Page 448
Mineral and organic soils: two types of acidity......Page 449
Nitrogen supply......Page 451
Soil heterogeneity......Page 453
Roots and mycorrhizas......Page 455
Nutrient addition experiments......Page 457
Trees, mineral weathering and pedogenesis?......Page 460
Concluding remarks......Page 461
Forests and peatswamps: a valuable combination......Page 467
Introduction......Page 469
Water balance studies in wetlands......Page 472
Water balance modelling approach......Page 476
Hydrological functions of peatswamps......Page 479
Acknowledgement......Page 480
Tropical montane cloud forests: definitions and occurrence......Page 482
Fog gauges......Page 485
Measurement of net precipitation......Page 486
Results of post-1993 rainfall and cloud interception studies in TMCF......Page 488
Transpiration and total forest water use......Page 491
Tropical montane cloud forests and water yield......Page 494
Putting cloud forests on the hydrological research agenda......Page 497
Part III: Forest disturbance, conversion and recovery......Page 513
Atmospheric systems......Page 517
The equatorial troughs......Page 518
Cyclones......Page 519
Inter-annual oscillations......Page 522
Tree mortality and tree-fall gaps......Page 523
Mass earth movements......Page 524
Floods and fluvial processes......Page 528
Volcanic eruptions and earthquakes......Page 533
Meteor impacts......Page 534
Modelling......Page 535
Conclusion......Page 536
Introduction......Page 541
Catchment-scale studies......Page 542
Evapotranspiration, catchment water-balance and water yield......Page 543
Flow-paths and rainfall-runoff behaviour......Page 545
Harvesting year impacts......Page 549
Recovery......Page 550
Rainfall regime controls......Page 552
Forestry land-use controls......Page 555
Conclusions......Page 556
Appendix 20.1 n. a. chappell the dynamic harmonic regression model......Page 557
Natural and wild fires in tropical rainforest......Page 561
Shifting cultivation......Page 562
Climate, especially rainfall......Page 563
Evapotranspiration......Page 564
Soil physical properties, infiltration and surface runoff......Page 565
Streamflow......Page 566
Effects of fire on erosion and sedimentation......Page 569
Leaching losses of dissolved elements......Page 570
Particulate nutrient losses......Page 574
Fire effects on nutrient losses to the atmosphere......Page 575
Traditional shifting cultivation......Page 576
Intensified shifting cultivation......Page 577
Wild fires in logged forests and secondary forests......Page 578
Effects of fire at the landscape level......Page 580
Towards integrated fire policy......Page 581
Recommendations for biogeochemical research......Page 582
Introduction......Page 589
Changes in energy and water balances during forest conversion and stabilisation of new land use......Page 590
Context and experimental design......Page 594
Experimental treatments......Page 596
Changes in storm runoff after land clearing (bare soil conditions)......Page 598
Evolution of runoff with time after application of the treatments......Page 600
Changes in flow pathways during forest conversion and stabilisation of new land use......Page 603
Erosion during forest conversion and stabilisation of new land use......Page 606
Soil fertility changes during forest conversion and stabilisation of new land use......Page 610
Concluding remarks......Page 613
Hydrological impacts of tropical forest conversion......Page 618
Large-scale hydrological impacts of tropical forest conversion: the importance of feedbacks......Page 619
How tropical forests manipulate their own climate......Page 621
Conclusions......Page 623
Changes in vegetation structure during forest recovery......Page 626
Phytomass accumulation, soil fertility and previous management intensity......Page 629
Changes in soil chemical properties during forest recovery......Page 631
Rainfall partitioning......Page 635
Soil water dynamics......Page 637
Albedo......Page 639
Aerodynamic roughness......Page 641
Surface conductance......Page 642
Conclusions......Page 645
Extent, development and importance of tropical tree plantations......Page 650
Hydrological impacts of forestation......Page 651
Water use of tropical tree plantations......Page 652
Effect of forestation on precipitation......Page 654
Effects of forestation on water yield......Page 655
Case study: effects of afforestation of subtropical grasslands in South Africa on water yield......Page 656
The link between productivity and water use......Page 658
Effect of forestation on low flows......Page 659
Effects of forestation on storm flows......Page 660
Forestation of degraded lands: prospects for improved flow regime......Page 661
Forestation Effects On Erosion And Sediment Yields......Page 666
Changes in soil chemical characteristics with land cover change......Page 668
Processes affecting soil nutrient levels during land clearing and plantation establishment......Page 669
Declining soil nutrient reserves in intensively managed plantations......Page 672
Conversion of grasslands into plantations......Page 673
Conclusions and recommendations......Page 674
Agroforestry as a management option......Page 680
Soil conservation: protection against erosion......Page 681
Soil organic matter and associated properties......Page 683
Water conservation and more efficient use of water......Page 685
The water balance of an agroforestry system......Page 686
Water use efficiency in tree/crop mixtures......Page 690
Resource capture: complementarity or competition?......Page 692
Concluding remarks......Page 694
Part IV: New methods for evaluating effects of land-use change......Page 699
Basics of remote sensing......Page 703
Forest cover......Page 711
Terrain attributes......Page 712
Soil characteristics......Page 713
Forest type, clearing and regrowth stage......Page 714
Forest condition and function......Page 720
Conclusion......Page 725
Introduction......Page 731
Selecting the test statistic......Page 732
Methods for checking assumptions......Page 733
Detecting climate change......Page 734
Advancing change detection in river flow data for the humid tropics......Page 735
Improvements in data collection......Page 736
Improvements in data access......Page 737
Significance levels......Page 739
Misconceptions......Page 741
Appendix 28.3 distribution-free approaches......Page 742
Summary of method for resampling......Page 743
Block resampling: resampling when data are not independent......Page 744
Introduction......Page 745
The basis for model choice......Page 747
Catchments as complex systems......Page 748
Scale assumptions......Page 749
Cumulative models......Page 751
Model comparisons......Page 753
The universal process model......Page 755
The universal model process: AMP......Page 756
The problem of validation......Page 757
An example of model development: south creek, babinda, (wyvuri, holding), northeast queensland......Page 759
Model development......Page 760
Incorporating tracer data into the model......Page 764
An alternative response function......Page 765
Conclusion......Page 767
Aims of the study......Page 770
Methodology......Page 772
Modelling of unregulated (natural) flow in gauged catchments......Page 773
Streamflow disaggregation procedure......Page 775
Disaggregation......Page 776
Calibration and testing......Page 777
Disaggregation results......Page 779
Discussion and conclusions......Page 781
Abilities......Page 782
Assumptions and limitations......Page 783
Introduction......Page 784
Topographically based, dynamic rainfall-runoff models......Page 786
(1) Point measurement of permeability......Page 789
(3) Permeability estimation by catchment-model inversion......Page 790
(4) Comparison of model-derived permeabilities with up-scaled field values......Page 791
(5) Hillslope-scale permeability estimation......Page 792
Conclusions......Page 793
Appendix 31.1 glossary of key modelling terms......Page 794
Isotope hydrograph separation basics......Page 798
Assumptions implicit in the technique......Page 801
What we know......Page 804
What we think we know......Page 805
A consensus?......Page 806
What is the most appropriate way to incorporate temporal variations in event water in IHS studies?......Page 807
How do temporal and spatial variations in hydrological linkages between landscape units (slopes – riparian zone – stream) affect a catchment’s isotopic and chemical response?......Page 808
How and why do IHS results vary with catchment scale?......Page 809
Controlled experiments that incorporate the use of environmental isotope tracers......Page 810
Integration of isotopic and geochemical tracers and hydrometric techniques with greater consideration of topographic properties......Page 811
Changes in water flowpaths......Page 812
Quantifying where mixing occurs in the landscape......Page 814
Conclusions......Page 815
An overview of erosion modelling......Page 818
GUEST methodology......Page 821
Hydrological drivers for GUEST......Page 824
Application of GUEST to tropical steeplands......Page 825
WEPP......Page 828
EUROSEM and LISEM......Page 830
A comparison of erosion prediction models......Page 832
Overland flows......Page 833
Conclusion......Page 835
Introduction......Page 839
The role of streams and rivers in the landscape......Page 840
Impacts of forest conversion......Page 842
Water flow to the stream......Page 843
Sedimentation......Page 847
Ecosystem energetics......Page 849
Nutrients......Page 850
Dissolved oxygen......Page 856
pH......Page 857
Other contaminants......Page 858
Concluding remarks......Page 859
Part V: Critical appraisals of best management practices......Page 865
The nature of tropical timber harvesting......Page 868
Reduced-impact logging (ril) techniques......Page 871
Research developments over the last decade in relation to catchment management in humid tropical forest areas......Page 872
Other relevant developments......Page 874
Experience with reduced-impact logging......Page 875
Key obstacles to sustainable forest management in tropical forests......Page 876
Concluding remarks......Page 877
Introduction......Page 880
The mc&i soil and water criterion of sustainable forestry management......Page 881
Performance standards associated with the indictors of the MC&I Soil and Water Criterion......Page 882
An example mc&i certification assessment......Page 883
Re-assessment of other MC&I criteria pertinent to hydrological impacts within the Selangor FMU......Page 884
Consistency with current hydrological science......Page 885
Skid trails......Page 886
Stream buffer zones......Page 887
Conclusions and recommendations......Page 889
Appendix 36.1 glossary of forestry terms used......Page 890
Introduction......Page 894
Tropical montane cloud forests......Page 895
Unstable slip-prone areas......Page 896
Riparian buffer zones......Page 897
Significant freshwater wetlands......Page 899
Mangrove forests......Page 900
High-quality water supply headwaters......Page 901
Soil limitations that will not sustain proposed use......Page 902
If clearing is happening, what guidelines are useful?......Page 903
Concluding remarks......Page 906
Introduction......Page 909
Support structures......Page 911
In-field practices......Page 921
Changing external factors......Page 927
Changing approaches: five new priorities......Page 928
Concluding comments......Page 930
Tropical forest loss: extent, patterns and causes......Page 934
Unique attributes of the humid tropical (forest) hydrological cycle......Page 936
Hydrological consequences of disturbing or clearing tropical forest: the scientific consensus......Page 938
Hydrological impacts of reforesting (degraded) humid tropical landscapes......Page 943
Chief hydrological research needs......Page 945
Outstanding economic and institutional issues......Page 949
Concluding remarks......Page 950