CONTENTS. Introduction. Chapter 1: forests. Rainforest. The Tropical Rainforest The Origin of the Tropical. Tropical Rainforests

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2 CONTENTS Introduction x Chapter 1: forests Rainforests The Tropical Rainforest The Origin of the Tropical Rainforest Tropical Rainforest Environments The Biota of Tropical Rainforests The Monsoon Forest Life in a Bromeliad Pool The Cloud Forest Population and Community Development and Structure of Tropical Rainforests Flying Trees: Aerial Seed Dispersal in the Panamanian Rainforest Rainforest Regeneration in Panama Apartments of the Rainforest: Communities in Tree Hollows Hitching a Ride: Seed Dispersal by Animals in the Panamanian Rainforest The Biological Productivity of Tropical Rainforests Eating the Rainforest: Herbivory and How Plants Defend Themselves The Status of the World s Tropical Forests The Temperate Forest The Origin of the Temperate Forest

3 Temperate Forest Environments 56 The Deciduous Forest 60 The Thorn Forest 68 Population and Community Development and Structure of Temperate Forests 69 The Biological Productivity of Temperate Forests 74 The Boreal Forest 75 The Origin of the Boreal Forest 75 The Distribution of the Boreal Forest 77 The Climate of the Boreal Forest 79 The Coniferous Forest 81 Boreal Forest Soils 83 The Biota and Its Adaptations 86 The Community Structure of Boreal Forests 98 The Biological Productivity of Boreal Forests 101 Deforestation 102 Notable Forests of the World 106 The Amazon and the Ituri 106 Other Forests 118 Chapter 2: forestry The History of Forestry The Ancient World Medieval Europe Modern Developments The Development of U.S. Policies The Classification and Distribution of Forests Gymnosperms Angiosperms

4 The Occurrence and Distribution of Forests The Purposes and Techniques of Forest Management Multiple-Use Concept Sustained Yield Forest Products Silviculture Range and Forage Recreation and Wildlife Watershed Management and Erosion Control Fire Prevention and Control Forest Fires Insect and Disease Control Agroforestry Urban Forestry Chapter 3: Grasslands The Origin of Grasslands Grassland Climates and Soils Grassland Biota Grassland Population and Community Development and Structure The Biological Productivity of Grasslands Grasses Prairies Savannas The Origin of Savannas Savanna Climates and Soils The Biota of Savannas The Population and Community Development and Structure of Savannas

5 The Biological Productivity of Savannas 204 Chaparral 206 Tundras 206 The Arctic Tundra 207 The Alpine Tundra 210 Notable Grasslands of the World 211 Buffalo Gap National Grassland 211 The Llanos 212 The Nyika Plateau 214 Oglala National Grassland 214 Serengeti National Park 215 Veld 217 Conclusion Glossary 226 Bibliography 228 Index

6 INTRODUCTION INTRODUCTION

7 7 Introduction 7 W hen attention to the smallest detail detracts from a person s comprehension of the larger situation at hand the big picture it is said that he or she can t see the forest for the trees. In the strictest sense, this idiom misses the mark. Ecologists and other biogeographic scientists, however, could easily argue that the only way to truly see a forest is to pay attention to the trees themselves and the activity occurring between each one. Ecosystems are geographic areas that are home to similar biota (plants and animals of an area) that have adapted to a particular region s environmental conditions. Forest ecosystems are dominated by trees, and grasslands are even easier to identify, as they are dominated by species of wild grasses. This book takes readers deep inside a variety of forests and out across the sweeping vistas created by various grasslands. In the process, they will encounter the elements inherent to each particular ecosystem, study the climatic conditions that surround these areas, and absorb the importance of each of these biomes to the overall balance of life on Earth. General observations will be supported through an examination of specific, notable forests and grasslands around the globe. Forests may be divided into a number of different categories, each defined by the type of trees they contain. Soil quality chiefly as it pertains to the abundance of nutrients the availability of sunlight, the amount of precipitation the soil receives, and the range of temperature the soil experiences determine which tree species grow in a particular area. Warm weather, high humidity, and copious amounts of rainfall favour the trees of the tropical rainforest, a highly diverse range of plants that includes palms, cycads, and the valuable hardwood teak, among others. In fact, the world s tropical rainforests, which are xi

8 7 Forests and Grasslands 7 located near the Equator, contain the most biological diversity of any ecosystem on the planet. High levels of rain and humidity tend to leach many nutrients from the soil in tropical rainforests, and the remaining minerals tend to be bound up in the plants themselves. What nutrients remain in the soil are concentrated mainly in the top layer. Consequently, trees with shallow root systems do well in this type of ecosystem. Trees of the rainforest are typically tall, reaching heights of 30 to 50 metres (98 to 164 feet). They generally grow close together, and their broad, rubbery leaves overlap high above the forest floor to form the canopy. A large number of species have adapted themselves to live among the lofty branches of the rainforest canopy: a diverse collection of insects, colourful parrots and birds of paradise, and tree-dwelling herbivores such as monkeys and flying squirrels. Smaller trees also populate the rainforest in an area called the understory, growing in whatever light gets filtered through the leafy roof of the canopy. The forest floor is covered with decomposing plant and animal matter and debris. Each of these forest layers (the canopy, the understory, and the forest floor) is home to diverse groups of animals that specialize on the opportunities provided by these unique environments. In contrast boreal, or taiga, forests occur in cold regions. The word boreal translates to northern, and climates in the north are notoriously harsh. The word taiga (Russian: little sticks ) originally referred to Russia s northern forests, but it is also used to describe boreal forests. The boreal forest is dominated by conifers, which have multiple small needles that store nutrients for longer periods than do broad leaves. Alternatively, broad-leaved trees depend on longer periods of warmth to maintain optimal rates xii

9 7 Introduction 7 of photosynthesis, a process that converts sunlight to chemical energy. As a result, broad-leaved trees are not fit to survive the long periods of darkness and cold characteristic of subarctic regions. The list of conifers includes firs, pines, spruces, and other species associated with the term evergreen. Aspen, birch, and larch, which have smallish, thin leaves with sharp edges or teeth, may also occur in some boreal forests. As one might imagine, winters are long and quite cold in the boreal forest. The growing season in this region is confined to a few months in the summer, with temperatures that, on average, don t reach much above 20 C (68 F). Consequently, permafrost is found over wide areas of the soil contained within these forests. Defined roughly as consistently or permanently frozen ground that lies below the ground s surface crust, permafrost inhibits the root systems of vegetation in boreal forests, thus allowing trees, shrubs, and plants that can thrive with shallow roots to dominate. Tundra regions, characterized by low, shrubby plants occur poleward of boreal forests. When considering the range of forest biodiversity, the boreal forest is relatively limited compared to the richly diverse rainforests of the tropics. The species of trees are few, but boreal forests contain a wide range of mosses and lichens that cover the forest floor. Other plants that grow in regions close to and within the Arctic Circle include quick-growing fireweed, orchids such as coral root and lady s slipper, that grow in association with fungi; and berries, such as cloudberry and lingonberry plants. Compared to the teeming faunas of the tropical rainforests, relatively few species of mammals, birds, and insects live in taiga habitats because of the challenging climatic conditions. Those that do occur have found ways to xiii

10 7 Forests and Grasslands 7 adapt to this forbidding environment. Many warmblooded mammals, such as the snowshoe hare and the lynx, generally have thick, heavy fur that keeps them warm. The coats of some of these animals also act as camouflage, changing from an earthy brown in the summer to a snowy white in the winter. To help them maneuver in terrain rife with ice and snow drifts, many taiga creatures possess disproportionately large feet that function like snowshoes, preventing them from sinking into the heavy snow cover. Migration is another adaptation useful in the boreal forest. Hundreds of bird species appear in the taiga during the summer months. However, most of those do not live there year-round. Many birds that live in southern climates during the winter travel north to the taiga because the air is thick with insects to eat during the warm growing season. Reindeer also migrate, moving south to find food during the winter and returning to the forest as temperatures warm. Between the hot, humid rainforests near the Equator and the boreal forests near the North Pole are temperate forests. Life in a temperate forest is marked by a moderate climate. These wooded areas, found primarily in North America, eastern Asia, and western Europe, are filled with stands of deciduous trees such as oaks, hickories, and maples, which sport broad-leaved foliage. Australian and Mediterranean temperate forests commonly have sclerophyllous trees (which are characterized by thick, hard leaves), such as Eucalyptus trees. Unlike conifers, which are able to store nutrients yearround and thus remain evergreen, deciduous trees are subject to the temperature and moisture fluctuations of the seasons. During winter months, temperature declines. Reduced sunlight and available water translate into lower xiv

11 7 Introduction 7 rates of photosynthesis. The leaves of deciduous trees turn different colours and fall off as the production of chlorophyll, a chemical pigment involved in photosynthesis, wanes. During the warm growing season in temperate regions, a number of plants flower and leaf. Also growing in the shade beneath the canopy of leaves are saplings the next generation of trees to populate the temperate forest. Many plants, saplings, and the berries or flowers they produce serve as food for the broad array of animals and birds that live in this region. The fauna of any particular forest generally reflects the species that are indigenous to the surrounding, nonforested region. Therefore, species composition varies according to the location of the forest. Because of the abundance of trees, however, all temperate woodlands are home to several kinds of birds and arboreal, or tree-dwelling, mammals. The latter includes squirrels in North America and certain species of monkeys in Asia. Nearly one-third of Earth s surface is occupied by forests of one type or another. Common sense, then, would dictate that forested regions are an important component of the biosphere the part of the Earth system that supports life and therefore are worthy of humankind s attention and respect. Managing, preserving, and studying the world s woodlands is the purview of those undertaking the science of forestry. An ancient activity practiced, to some extent, since at least the height of the Roman Empire, forestry has evolved from simply a way to ensure a steady supply of wood to an ecological and cultural imperative in many parts of the world. Forests provide timber, recreational opportunities, a defense against soil erosion, habitat for wildlife, and other environmental services. Forestry is designed to protect and perpetuate valuable woodland resources. xv