California's North Coast provides the only such environment in the world. A combination of longitude, climate, and elevation limits the redwoods' range to a few hundred coastal miles. The cool, moist air created by the Pacific Ocean keeps the trees continually damp, even during summer droughts. These conditions have existed for some time, as the redwoods go back 20 million years in their present range. Exactly why the redwoods grow so tall is a mystery.
Theories continue to develop but proof remains elusive.
The trees can reach ages of 2,000 years and regularly reach 600 years. Resistance to natural enemies such as insects and fire are built-in features of a coast redwood. Diseases are virtually unknown and insect damage insignificant thanks to the high tannin content of the wood. Thick bark and foliage that rests high above the ground provides protection from all but the hottest fires. The redwoods' unusual ability to regenerate also aids in their survival as a species.