Sequoiadendron giganteum (giant sequoia; also known as giant sequoia; Sierra sequoia, Sierran sequoia, Wellingtonia, or simply large tree - a pseudonym also used by John Muir [2]) is the only living species in the genus Sequoiadendron and is one of three species, the needle known as Sequoia deciduous trees with Sequoia sempervirens (coastal sequoia) and Metasequoia glyptostroboides (dawn sequoia), classified in the Cupressaceae family of the Sequoioideae subfamily. Giant sequoia specimens are the largest trees in the world. [3] The common use of the name Sequoia generally refers to Sequoiadendron giganteum, which occurs only naturally in groves on the western slopes of California's Sierra Nevada Mountains. The oldest known giant sequoia is 3,200-3,266 years old.

It was assumed that the etymology of the genus name - originally in the Yosemite Book [4] written by Josiah Whitney in 1868 - would be in honor of Sequoyah (1767-1843), who was the inventor of the Cherokee curriculum. [5] An etymological study published in 2012 concluded that the name was actually the Austrian Stephen L. Endlicher responsible. Endlicher, a linguist and botanist, corresponded with experts in the Cherokee language, including the Sequoyah, whom he admired. He also, incidentally, realized that the genus could be described as sequi (meaning to follow) in Latin because the number of seeds per cone in the newly classified breed was mathematically aligned with the other four genera in the lower order. Endlicher thus named it "Sequoia" as both a description of the genus of the tree and as an honor to the native man he admired. [6]

Giant sequoia specimens are the largest individual trees in the world. [3] They grow to an average height of 50–85 m (164–279 ft) with trunk diameters ranging from 6–8 m (20–26 ft). Record trees measured 94.8 m (311 ft) tall. With research figures taken out of context, fuselage diameters of 17 m (56 ft) were claimed. [7] The example known to have the largest diameter at chest height is the General Grant tree at 8.8 m (28.9 ft). [8] Between 2014 and 2016, coastal sequoia specimens were found to have larger trunk diameters than any known giant sequoia. [9] The bodies of coastal redwoods become thinner at lower heights than giant sequoias, which have more columnar stems that retain larger diameters to greater heights.