ABSTRACT
Tropical rain forests thrive in the warm, wet environments of the humid tropics. The superb conditions for plant growth there allow a profusion of forests with a great diversity in species composition, but at the same time give rise to poor soils that make it difficult for farmers to capitalize on them. Farming can easily become unsustainable if practised too intensively on low quality deforested land. The great contribution that tropical rain forests make to the world’s biological diversity is not just in their huge species content but in the variety of different types of tropical rain forest. The next section looks at each of the main types of rain forest in turn, and is followed by a review of the distribution of forests in the humid tropics. We lack estimates of the global and national areas of tropical rain forest and are forced instead to list areas of ‘tropical moist forest’ – the collective term for all closed forest in the humid tropics, including both tropical rain forest and the tropical moist deciduous forest found in seasonal areas. Crucial to the debate about tropical deforestation is the rate at which it occurs, but since estimates are influenced by the way in which deforestation is defined the final section of the chapter examines this matter and suggests the need to widen the usual definition, which requires forest clearance to encompass less severe human impacts.
