Specifically, it refers to two species of coniferous evergreen trees:

* Coast redwood (Sequoia sempervirens): This is the tallest tree species in the world, native to the coast of California.

* Giant sequoia (Sequoiadendron giganteum): While not as tall as coast redwoods, giant sequoias are the largest trees in the world by volume. They are found in the Sierra Nevada mountain range of California.