Established in 1968, Redwood National Park in northern California is home to the coastal redwoods, the tallest tree species in the world. Redwoods are evergreen conifers with broad crowns and drooping branches that often begin as high as 100 feet off the ground and can measure six feet in diameter. Named for the color of their fibrous bark, redwoods can grow to over 360 feet tall and as large as 20 feet in diameter.

Redwoods are some of Earth's most ancient trees, living as long as 2,000 years. Approximately 160 million years ago, during the Jurassic period, redwoods covered most of North America. Logging in the 1850s diminished their range in California to four percent of the remaining two million acres, resulting in what is now 88,000 acres. At that time, trees were harvested in areas like Redwood National Park where, according to fossil records, they have thrived for at least 20 million years due, in part, to the area's ideal climate. With the ability to take in moisture through their leaves, redwoods flourish along Pacific coastal environments in southern Oregon and northern California, where there is plentiful fog and rain.

Redwoods grow exceedingly quickly in ideal conditions. Given abundant sunlight and precipitation, damp soil, and a moderate climate, seedlings can grow as much as six or eight feet in a single season. They are virile and prolific, reproducing both sexually (by seed) and asexually (from shoots that form on roots, rounded outgrowths called burls, or fallen trees). In fact, the coastal redwoods are the only conifers that can clone themselves in this way. A stump will regenerate itself by producing a circle of saplings around its base, even after a tree is burned.

Hundreds of gallons of water are transported from the roots to the crown of a single tree each day through the part of the plant's vascular system called the xylem. The height of redwood trees, in fact, is limited by the forces of capillary action needed to transport water through the xylem to the top of the tree. A single air bubble forming from tension in a water column can break the column, causing the farther-reaching parts of a tree to die back.

Redwoods are fire-adapted species and redwood forests require burning to grow and prosper. Fire occurs naturally in stands of redwoods, and it is often prescribed in managed settings to clear undergrowth that might compete with redwoods for resources; the redwoods themselves remain protected by the tree's thick bark. Fire plays a role in reproduction, as forest fires release nutrients back into the soil and provide ideal conditions for germination and growth.

The coastal redwood is a valuable renewable natural resource. Although it can take 40 or 50 years to grow redwood timber for harvest and sale, it takes between 500 and 1,000 years to fully restore a mature forest. Stands are cultivated and managed for logging for commercial purposes. Among other things, the wood is used for roofing and siding on buildings, as well as for cabinetry, furniture, and fence posts. The coastal redwood makes desirable timber because it is durable, lightweight, straight-grained, and resistant to disease and decay. Its powerful tannins prevent fungal growth and bug infestation. Even fallen trees can take centuries to decay.

To learn more the structure of trees, check out Shape of Things: Trees and Life of a Tree.

To find out more about how plants grow, check out Photosynthesis and Illuminating Photosynthesis.

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