The interactions between the sun, earth's atmosphere, water, and the inorganic and organic components of soil combine to support any plant communities. The plants, the animals, and the environment together create a complete ecosystem, incredibly complex and only partially understood. While many plant ecosystems are ancient and well established, they are quite fragile. For 45 million years tropical forests have expanded and retreated across much of the world but are now disappearing faster than any other natural community. Tropical forests, whether evergreen rainforests or deciduous mountain forests, are being exploited by ever-expanding human populations. Unfortunately this is happening before we have thoroughly studied forests' contributions to the earth's natural processes.

Trees are self-sufficient plants that create the food they need from sunlight, carbon dioxide, and water. Plants form the basis of earth's food chains, and life, as we understand it, would cease without this amazing process called photosynthesis. As plants grow and reproduce, they weave the framework for most habitats while they create and maintain the natural balances of gases, nutrients, soils and water. During photosynthesis plants consume carbon dioxide, an animal waste product, and produce oxygen, an essential gas to most animals.