Sequoia is closely related to Bishop Pine and Knobcone Pine, hybridizing readily with both species; it is distinguished from the former by needles in threes (not pairs), and from both by the cones not having a sharp spine on the scales.
The name sequoia is sometimes used as a general term for the subfamily Sequoioideae in which this genus is classified, together with Sequoiadendron (Giant Sequoia) and Metasequoia (Dawn Redwood); as a common name, it usually refers to Sequoiadendron.
Coast Redwoods occupy a narrow strip of land approximately 750 km (470 miles) in length and 8–75 km (5–47 miles) in width along the Pacific coast of North America; the elevation range is mostly from 30–750 m, occasionally down to sea level and up to 920 m (about 3,000 feet) (Farjon 2005). They usually grow in the mountains where there is more precipitation from the incoming moisture off the ocean. The tallest and oldest trees are found in deep valleys and gullies, where year-round streams can flow, and fog drip is regular. The trees above the fog layer, above about 700 m, are shorter and smaller due to the drier, windier, and colder conditions. In addition, tanoak, pine and Douglas-fir often crowd out redwoods at these elevations. Few redwoods grow close to the ocean, due to intense salt spray, sand, and wind.