Structure and Climate in Tropical Rain Forest

The similarity of tropical rain forests of comparable habitat around the world has struck many observers. This review first discusses similarities in lowland tropical rain forests (lowland forests between the tropics, which in most months receive more rain than they can transpire). Primary concern is with normal rain forest, not swamps or heath forest. These forests are also of similar productivity, which reflects an extraordinary similarity of climate, particularly with respect to evaporation: productivity of these forests appears to vary seasonally with transpiration rate. Second, this review discusses montane rain forest, in whose frequently saturated climates structure is often very obviously related to transpiration rate. A marine biologist might well object to treating forest structure without mention­ ing herbivores; therefore, I estimate the impact of vertebrate and insect on fruit and leaf in the old successional forest of Barro Colorado Island, Panama, then explore the rhythms of abundance and scarcity by which tropical forests defend themselves.