Book contents
- Only in Africa
- Only in Africa
- Copyright page
- Dedication
- Contents
- Foreword
- Preface
- Abbreviations
- Part I The Physical Cradle: Land Forms, Geology, Climate, Hydrology and Soils
- Part II The Savanna Garden: Grassy Vegetation and Plant Dynamics
- Chapter 6 Forms of Savanna: From Woodland to Grassland
- Chapter 7 How Trees and Grasses Grow and Compete
- Chapter 8 Plant Demography and Dynamics: Fire Traps
- Chapter 9 Paleo-savannas: Expanding Grasslands
- Part II Synthesis: Savanna Structure and Dynamics
- Part III The Big Mammal Menagerie: Herbivores, Carnivores and Their Ecosystem Impacts
- Part IV Evolutionary Transitions: From Primate Ancestors to Modern Humans
- Appendix Scientific Names of Extant Animal and Plant Species Mentioned in the Book Chapters (Ecologically Conservative with Regard to Species Recognition)
- Index
- References
Chapter 7 - How Trees and Grasses Grow and Compete
from Part II - The Savanna Garden: Grassy Vegetation and Plant Dynamics
Published online by Cambridge University Press: 09 September 2021
Book contents
- Only in Africa
- Only in Africa
- Copyright page
- Dedication
- Contents
- Foreword
- Preface
- Abbreviations
- Part I The Physical Cradle: Land Forms, Geology, Climate, Hydrology and Soils
- Part II The Savanna Garden: Grassy Vegetation and Plant Dynamics
- Chapter 6 Forms of Savanna: From Woodland to Grassland
- Chapter 7 How Trees and Grasses Grow and Compete
- Chapter 8 Plant Demography and Dynamics: Fire Traps
- Chapter 9 Paleo-savannas: Expanding Grasslands
- Part II Synthesis: Savanna Structure and Dynamics
- Part III The Big Mammal Menagerie: Herbivores, Carnivores and Their Ecosystem Impacts
- Part IV Evolutionary Transitions: From Primate Ancestors to Modern Humans
- Appendix Scientific Names of Extant Animal and Plant Species Mentioned in the Book Chapters (Ecologically Conservative with Regard to Species Recognition)
- Index
- References
Summary
This chapter considers the mechanisms of growth and competition among trees and grasses in the context of seasonally restricted and erratic rainfall. Competition operates largely below-ground, for water and nutrients, rather than for light, and primarily between grasses and tree seedlings. Fires promoted by seasonally dry grasses restrict growth by tree saplings. Grasses are the superior competitors unless the woody canopy closes. Most savanna trees are deciduous, while grasses become dormant and dry above-ground during the dry season, providing fuel for fires. Deeper roots enable trees to access water at deeper levels, but grasses capture water and nutrients at shallow depths faster than trees. C4 photosynthesis enables grasses to grow rapidly while moisture is available despite low atmospheric carbon dioxide. Grasses produce more biomass annually than woody plants in savannas.
Keywords
- Type
- Chapter
- Information
- Only in AfricaThe Ecology of Human Evolution, pp. 97 - 117Publisher: Cambridge University PressPrint publication year: 2021
References
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