If you access the internet, the key words “canopy crane” will lead you to World Wide Web pages showing giant construction cranes poised over green treescapes. Most of the pages tell about scientists using the cranes to study life in the treetops, or canopies, of forests. These are some of Earth’s least explored environments.

Virtually unstudied until about twenty five years ago, forest canopies are one of nature’s great showplaces of different kinds (species) of living organisms. Biologists estimate that fully half of the 5 million to 50 million species that exist on Earth may spend all or much of their in forest treetops. The canopies of tropical rain forests, areas near the equator where yearly rainfall often exceeds 200 centimeters (80 inches), harbor the greatest number of species. Equally wet forests in the coastal regions of western Canada and the northwestern United States also are home to remarkable numbers.

The big crane called the Wind River Canopy Crane Research Facility stands in an evergreen rain forest in the Cascade Mountains of southern Washington State. The crane’s vertical tower is about 80 meters high, as tall as a 25- story building. The crane’s horizontal boom rotates around the tower, looming over 6 acres of forest that have never been logged or otherwise significantly altered by human activity. The dominant trees have are 60 meter-high firs and hemlocks that have been growing for about 500 years. Over the centuries, a great variety of organisms have colonized the canopy environment.

To use the Wind River crane, a researcher climbs a ladder in the vertical tower and steps into the yellow gondola. An operator then rotates the crane to the desired position, and a trolley under the horizontal boom runs the gondola out over the treetops. Forests researchers and Wind River project director Dr. Jerry Franklin expresses his enthusiasm for having direct access to the canopy this way: “Trees are one of Earth’s main points of contact with the air. This is our chance to learn about the dialogue between trees and the atmosphere.”

The crane’s gondola can also be lowered into the treetops, and descending quietly among the big trees, you really begin seeing, hearing, and smelling the canopy’s varied life. Brown and greenish fungi, lichens, and thick earthy mats of moss cling to the larger branches. Collectively called epiphytes (Greek for “on plants”), these organisms often take hundreds of years to fully colonize a tree. Hidden in moist soil that builds up in the moss mats are thousands of small animals- frogs, salamanders, beetles, spiders, mites, and many others. Some are found nowhere else.

A quiet summer evening is often the best time to experience a canopy’s rich array of animal life. Looking up from the Wind River gondola, your eye might catch the split-second shadow of a flying squirrel across a bright moon. Common in Northern American forests, but rarely seen because they are active only at night, these foot-long rodents speed-glide between the big trees. Insects are especially abundant in the canopy twilight, and bats flit about, often eating close to their own body weight in insects in a single night. Owls, another group of nocturnal hunters, are silent on the wing, but each species has its own distinctive hoot.

The enormous variety of living organisms in forest canopies and the new science of canopy research set the stage for this chapter’s introduction to biology, the scientific study of life.