Earth Science: Forests As Habitats and Economic Areas
Forests provide habitats for myriad animal and plant species and support the subsistence of millions of people. But they are in great danger. About half of the original forests worldwide have already been destroyed.
Between the subterranean roots and high-reaching crowns of the trees, a forest provides an abundance of ecological niches. In the treetop levels of the rain forest, a multitude of birds and small mammals, monkeys, and sloths make their homes. In temperate forests, tree crowns serve many birds of prey, such as hawks, as well as being a nesting area for wood warblers such as the willow warbler.
Branched, leafy trees in moist tropical forests are the home of agile climbers and fliers such as butterflies, tree frogs, tree snakes, parrots, and hummingbirds. In cooler climates typical forest birds such as chaffinch, jay, and coal tit, as well as striped and flying squirrels, are found. Numerous invertebrate animals, such as caterpillars, beetle larvae, spiders, and mites, live underneath the tree bark, attracting insect-eating birds.
Owls, wild ducks, bats, or squirrels occupy natural tree hollows or those hollowed out by wood- peckers. Leaves, seeds, and fruits from trees and bushes feed many mammals, including monkeys, mice, and hedge-hogs. Seeds and undergrowth provide an important nutritional basis for herbivores and omnivores such as deer, elephants, and elk.
These in turn provide food for predators, such as martens, bears, jaguars, lynx, or wolves. Finally, even a dead tree provides nutrition for decay-enhancing organisms, such as insects, fungi, mosses, and microorganisms. They break down plant material, thus completing the cycle of nature. People have long used timber as a building and heating material.
Although the negative effects of overexploitation are widely known, precious rain forest woods, such as teak, are still in demand. Forests are also “farmed”—fast-growing trees, such as Douglas fir, are planted and later logged. Plantations promise quick profits, but due to their lack of a natural ecosystem, they are susceptible to massive infestations with so-called forest pests such as bark beetles.
THE RAIN FOREST LABORATORY STORE
Rain forests are gigantic reservoirs of natural medicines and other bioactive substances. For example, the bark of the cinchona tree from South America provided the effective malaria medication quinine for many years.
Secretions from an Australian tree frog have yielded a new antibiotic that is effective even against resistant germs. So far only a fraction of this magnificent drug- store of nature has been explored.