The giant sequoia (Sequoiadendron giganteum) is the world's most massive tree, and arguably the largest living organism on Earth. It is neither the tallest extant species of tree (that distinction belongs to the coast redwood), nor is it the widest (that distinction belongs to the African baobab or the Montezuma cypress), nor is it the longest-lived (that distinction belongs to the Great Basin bristlecone pine). However, with a height of 87 meters (286 ft) or more, a circumference of 34 meters (113 ft) or more, an estimated bole volume of up to 1,490 cubic meters (52,500 cu ft), and a documented lifespan of 3266 years, the giant sequoia is among the tallest, widest, and longest-lived of all organisms on Earth.
Giant sequoias grow in well-defined groves in California mixed evergreen forests, along with other old-growth species such as California incense cedar. Because most of the neighboring trees are also quite large, it can be difficult to appreciate the size of an individual giant sequoia. The largest giant sequoias are as tall as a 26-story building, and the width of their bases can exceed that of a city street. They grow at such a rate as to produce roughly 1.1 cubic meters (40 cu ft) of wood each year, approximately equal to the volume of a 50-foot-tall tree one foot in diameter. This makes them among the fastest growing organisms on Earth, in terms of annual increase in mass.