Tropical Trees and Forests

This book is not an exhaustive survey of known information in the manner of a text-book -the subject is much too big for this to be possible in a relatively concise volume­ but presents a point of view. We are concerned ultimately with the analysis of tropical ecosystems, mainly forests, in terms of their constituent units, the individual trees. Many different approaches are possible in the analysis of tropical forests. A simple one is to treat the trees as obstacles which in a military sense intercept projectiles or are a hin­ drance to foot soldiers (ADDOR et aI., 1970). A similar ap­ proach might be adopted by an engineer confronted by a forest which has to be removed to permit road construc­ tion. The timber merchant is concerned with the ability of a forest to yield saleable lumber. The interest here is in the size of the larger trunks with some concern for the kinds of trees. At a less destructive level the scientist aims to compre­ hend the forest from many different points of view. The forester himself, in conjunction with the taxonomist, will wish to analyze the floristic composition of the forest and perhaps account for species diversity in an evolutionary time scale (e.g., FEDOROV, 1966; ASHTON, 1969). The evolu­ tionary biologist in his turn may be concerned with repro­ ductive strategies in forest trees (e.g., BAWA, 1974), espe­ cially in a comparative way.

1 Introduction.- A. What is a Tree?.- I. Definitions.- II. Tree Making.- III. Apical Meristems and Tree Construction.- 1. Trees Built by One Meristem.- 2. Trees with Modular Construction.- 3. Trees with Trunk-Branch Differentiation.- 4. Trees with Changes in Orientation of Axes.- B. The Botanical World of the Tropics.- I. Distribution and Size of Flowering Plant Families.- II. Tropical Floras as Tree Floras.- III. Floristic Richness in Limited Areas.- IV. Geographic Locations.- V. Climate and Tree Growth in the Tropics.- 2 Elements of Tree Architecture.- A. The Initiation of the Tree.- I. Seedling Morphology.- II. Juvenility and Phases of Development.- B. Apical Meristems and Buds.- I. Terminal Buds.- II. Bud Composition.- III. Lateral Buds.- IV. Secondary Bud Complexes.- C. Extension Growth in Tropical Trees.- I. Introductory Remarks.- II. Rhythmic Growth.- 1. Rhythmic Growth in Hevea.- 2. Preformation and Neoformation.- 3. Further Examples of Rhythmic Growth.- III. Continuous Growth.- 1. Palms.- 2. A Dicotyledon.- D. Phyllotaxis and Shoot Symmetry.- I. Primary Orientation.- II. Secondary Orientation.- E. Branching: Dynamics.- I. Branch Order Terminology.- II. Syllepsis and Prolepsis.- 1. Definitions and Descriptions.- 2. Historical Usage of the Terms.- 3. Apical Dominance.- III. Continuous and Diffuse (Intermittent) Branching.- F. Branch Polymorphism: Long Shoots.- I. Orthotropy and Plagiotropy.- 1. Strict Orthotropy of Trunk Axes.- 2. Orthotropic Branches.- 3. Plagiotropic Branches (Reversible).- 4. Plagiotropic Branches (Nonreversible).- 5. Phyllomorphic Branches.- II. Branch Complexes and Sympodial Growth.- III. Plagiotropy and Syllepsis.- IV. Plagiotropy in Monocotyledons.- G. Branch Polymorphism: Short Shoots.- I. In Dicotyledons.- II. In Monocotyledons.- H. Abscission.- I. Inflorescence.- I. Flowering and Shoot Construction.- II. Continuous Flowering.- III. Cauliflory.- IV. Floral Phenology.- J. Radial Growth: Conifers and Dicotyledons.- I. Growth Rings.- II. Growth Rings in Tropical Trees.- III. Cambial Activity in Tropical Trees.- K. Radial Growth: Some Variations.- I. Trees Without Secondary Growth.- 1. The Palm-Habit.- 2. Bamboos.- 3. Tree Ferns.- II. Arborescent Monocotyledons with Secondary Growth.- III. Cycads.- L. Root Systems in Tropical Trees.- 3 Inherited Tree Architecture.- A. The Concept of Architecture and Architectural Tree Models.- I. The Architectural Continuum.- II. Recognition and Study of the Architectural Models.- III. Nomenclature.- IV. Recapitulation of Growth Criteria Used in Recognizing Models.- V. Size and Architectural Proportions ― Corner’s Rules.- B. Illustrated Key to the Architectural Models of Tropical Trees.- C. Descriptions of Architectural Tree Models.- I. Illustrations of the Models ― a Note of Explanation.- II. Monoaxial and Polyaxial Trees.- III. Plan of the Descriptive Arrangement.- IV. Monoaxial Trees.- Holttum’s Model.- Corner’s Model.- V. Polyaxial Trees.- 1. Vegetative Axes all Equivalent and Orthotropic.- Tomlinson’s Model.- Schoute’s Model.- Chamberlain’s Model.- McClure’s Model.- 2. Vegetative Axes Differentiated into Trunk and Branch.- Leeuwenberg’s Model.- Koriba’s Model.- PrÉvost’s Model.- Fagerlind’s Model.- Petit’s Model.- Nozeran’s Model.- Aubréville’s Model.- Massart’s Model.- Roux’s Model.- Cook’s Model.- Scarrone’s Model.- Stone’s Model.- Rauh’s Model.- Attims’ Model.- 3. Trees with Mixed Axes ― an Introduction.- Mangenot’s Model.- Champagnat’s Model.- Troll’s Model.- D. Architecture of Lianes.- I. Lianes with an Architecture Conforming Closely to That of Tree Models.- II. Lianes with an Architecture Not Conforming to That of Known Tree Models.- E. Architecture of Herbs: Miniaturization in Relation to Tree Models.- 1. Miniaturization of Models.- 2. Origin of New Models.- F. Architecture of Fossil Trees.- 4 Opportunistic Tree Architecture.- A. Reiteration.- I. Reiteration as a Morphological Phenomenon.- II. The Organ Complexes Built by Reiteration.- 1. The Tree in the Forest.- 2. The Free-Standing Tree.- B. Energetics.- I. Trees in Their Environment.- 1. Energy Exchange.- 2. Energetic Efficiency.- 3. Energetic Economy in Whole Architecture.- 4. Spatial Disposition of Surface in Tree Crowns.- 5. Height-Diameter Relationship in Trees.- 6. Flexibility and Rigidity in Volume-Surface Integration.- II. Energy Exchange and Production.- III. Size and Architectural Proportions.- IV. Vigor and Death in Forest Trees.- V. Ecological Strategies of Trees.- C. Growth Potential of Forest Trees.- I. Trees of the Future.- II. Trees of the Present.- III. Trees of the Past.- IV. The Morphological Inversion Point.- V. Gymnosperms and Forests.- D. A Note on Floristics.- 5 Forests and Vegetation.- A. The Architecture of Forest Plots.- I. The Layered Forest.- II. The Architecture of Homeostatic Forest Plots.- 1. The Set of the Present.- 2. The Set of the Future.- 3. The Set of the Past.- 4. The Infrastructural Set: Meristems.- 5. Geometry of Homeostatic Forests with Their Vertical Gradients.- III. Examples of Forest Plots.- 1. A Forest at Montagne La Fumée, Saül, French Guiana.- 2. A Forest at Trois Sauts, Oyapock River, French Guiana.- 3. A Forest at Tom Swamp, Harvard Forest, Massachusetts.- IV. Morphological and Ecological Inversion Surfaces.- V. Variations in Homeostatic Architecture.- 1. Forest Imbrication on Slopes.- 2. Intertwining of Structural Ensembles.- 3. The Riverside Effect in Whole Canopies.- 4. Architecture of Forests with Strangling Figs 365 B. Sylvigenesis.- I. Disturbances of Existing, Functioning Forests.- II. The Chablis.- III. Homeostasis in the Forest.- IV. Sylvigenetic Cycles and Phases.- V. Tree Ecotopes.- VI. Biological Nomads and Towering Trees.- Concluding Remarks.- References.- Index of Plant Names and Their Models.