Sequoiadendron giganteum (giant sequoia; also known as giant redwood, Sierra redwood, Sierran redwood, Wellingtonia or simply big tree—a nickname also used by John Muir) is the sole living species in the genus Sequoiadendron, and one of three species of coniferous trees known as redwoods, classified in the family Cupressaceae in the subfamily Sequoioideae, together with Sequoia sempervirens (coast redwood) and Metasequoia glyptostroboides (dawn redwood). Giant sequoia specimens are the most massive trees on Earth. The common use of the name sequoia usually refers to Sequoiadendron giganteum, which occurs naturally only in groves on the western slopes of the Sierra Nevada mountain range of California.
|The "Grizzly Giant" in the Mariposa Grove, Yosemite National Park|
|Natural range of the California members of the subfamily Sequoioideae
red – Sequoiadendron giganteum
green – Sequoia sempervirens
The giant sequoia is listed as an endangered species by the IUCN, with fewer than 80,000 trees remaining. Since its last assessment as an endangered species in 2011, it was estimated that another 13-19% of the population (or 9,761–13,637 mature trees) was destroyed during the Castle Fire of 2020 and the KNP Complex & Windy Fire in 2021, events attributed to fire suppression, drought and global warming. Despite their large size and adaptations to fire, giant sequoias have become severely threatened by a combination of fuel load from fire suppression, which fuels extremely destructive fires that are also boosted by drought and climate change. These conditions have led to the death of many populations in large fires in recent decades. Prescribed burns to reduce available fuel load may be crucial for saving the species.
The etymology of the genus name has been presumed—initially in The Yosemite Book by Josiah Whitney in 1868—to be in honor of Sequoyah (1767–1843), who was the inventor of the Cherokee syllabary. An etymological study published in 2012 concluded that Austrian Stephen L. Endlicher is actually responsible for the name. A linguist and botanist, Endlicher corresponded with experts in the Cherokee language including Sequoyah, whom he admired. He also realized that coincidentally the genus could be described in Latin as sequi (meaning to follow) because the number of seeds per cone in the newly classified genus aligned in mathematical sequence with the other four genera in the suborder. Endlicher thus coined the name "Sequoia" as both a description of the tree's genus and an honor to the indigenous man he admired.
Giant sequoia specimens are the most massive individual trees in the world. 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 have been measured at 94.8 m (311 ft) tall. Trunk diameters of 17 m (56 ft) have been claimed via research figures taken out of context. The specimen known to have the greatest diameter at breast height is the General Grant tree at 8.8 m (28.9 ft). Between 2014 and 2016, it is claimed that specimens of coast redwood were found to have greater trunk diameters than all known giant sequoias - though this has not been independently verified or affirmed in any academic literature. The trunks of coast redwoods taper at lower heights than those of giant sequoias which have more columnar trunks that maintain larger diameters to greater heights.
The oldest known giant sequoia is 3,200–3,266 years old based on dendrochronology. Giant sequoias are among the oldest living organisms on Earth, and are the verified third longest-lived tree species after the Great Basin bristlecone pine and alerce. Giant sequoia bark is fibrous, furrowed, and may be 90 cm (3 ft) thick at the base of the columnar trunk. The sap contains tannic acid, which provides significant protection from fire damage. The leaves are evergreen, awl-shaped, 3–6 mm (1⁄8–1⁄4 in) long, and arranged spirally on the shoots.
The giant sequoia regenerates by seed. The seed cones are 4–7 cm (1+1⁄2–3 in) long and mature in 18–20 months, though they typically remain green and closed for as long as 20 years. Each cone has 30–50 spirally arranged scales, with several seeds on each scale, giving an average of 230 seeds per cone. Seeds are dark brown, 4–5 mm (0.16–0.20 in) long, and 1 mm (0.04 in) broad, with a 1-millimeter (0.04 in) wide, yellow-brown wing along each side. Some seeds shed when the cone scales shrink during hot weather in late summer, but most are liberated by insect damage or when the cone dries from the heat of fire. Young trees start to bear cones after 12 years.
Trees may produce sprouts from their stumps subsequent to injury, until about 20 years old; however, shoots do not form on the stumps of mature trees as they do on coast redwoods. Giant sequoias of all ages may sprout from their boles when branches are lost to fire or breakage.
A large tree may have as many as 11,000 cones. Cone production is greatest in the upper portion of the canopy. A mature giant sequoia disperses an estimated 300–400 thousand seeds annually. The winged seeds may fly as far as 180 m (590 ft) from the parent tree.
Lower branches die readily from being shaded, but trees younger than 100 years retain most of their dead branches. Trunks of mature trees in groves are generally free of branches to a height of 20–50 m (70–160 ft), but solitary trees retain lower branches.
The natural distribution of giant sequoias is restricted to a limited area of the western Sierra Nevada, California. They occur in scattered groves, with a total of 68 groves (see list of sequoia groves for a full inventory), comprising a total area of only 144.16 km2 (35,620 acres). Nowhere does it grow in pure stands, although in a few small areas, stands do approach a pure condition. The northern two-thirds of its range, from the American River in Placer County southward to the Kings River, has only eight disjunct groves. The remaining southern groves are concentrated between the Kings River and the Deer Creek Grove in southern Tulare County. Groves range in size from 12.4 km2 (3,100 acres) with 20,000 mature trees, to small groves with only six living trees. Many are protected in Sequoia and Kings Canyon National Parks and Giant Sequoia National Monument.
The giant sequoia is usually found in a humid climate characterized by dry summers and snowy winters. Most giant sequoia groves are on granitic-based residual and alluvial soils. The elevation of the giant sequoia groves generally ranges from 1,400–2,000 m (4,600–6,600 ft) in the north, to 1,700–2,150 metres (5,580–7,050 ft) to the south. Giant sequoias generally occur on the south-facing sides of northern mountains, and on the northern faces of more southerly slopes.
High levels of reproduction are not necessary to maintain the present population levels. Few groves, however, have sufficient young trees to maintain the present density of mature giant sequoias for the future. The majority of giant sequoia groves are currently undergoing a gradual decline in density since European settlement.
While the present day distribution of this species is limited to a small area of California, it was once much more widely distributed in prehistoric times, and was a reasonably common species in North American and Eurasian coniferous forests until its range was greatly reduced by the last ice age. Older fossil specimens reliably identified as giant sequoia have been found in Cretaceous era sediments from a number of sites in North America and Europe, and even as far afield as New Zealand and Australia.
In 1974, a group of giant sequoias was planted by the United States Forest Service in the San Jacinto Mountains of Southern California in the immediate aftermath of a wildfire that left the landscape barren. The giant sequoias were rediscovered in 2008 by botanist Rudolf Schmid and his daughter Mena Schmidt while hiking on Black Mountain Trail through Hall Canyon. Black Mountain Grove is home to over 150 giant sequoias, some of which stand over 6.1 m (20 ft) tall. This grove is not to be confused with the Black Mountain Grove in the southern Sierra. Nearby Lake Fulmor Grove is home to seven giant sequoias, the largest of which is 20 m (66 ft) tall. The two groves are located approximately 175 mi (282 km) southeast of the southernmost naturally occurring giant sequoia grove, Deer Creek Grove.
It was later discovered that the United States Forest Service had planted giant sequoias across Southern California. However, the giant sequoias of Black Mountain Grove and nearby Lake Fulmor Grove are the only ones known to be reproducing and propagating free of human intervention. The conditions of the San Jacinto Mountains mimic those of the Sierra Nevada, allowing the trees to naturally propagate throughout the canyon.
Giant sequoias are in many ways adapted to forest fires. Their bark is unusually fire resistant, and their cones will normally open immediately after a fire. Giant sequoias are a pioneer species, and are having difficulty reproducing in their original habitat (and very rarely reproduce in cultivation) due to the seeds only being able to grow successfully in full sun and in mineral-rich soils, free from competing vegetation. Although the seeds can germinate in moist needle humus in the spring, these seedlings will die as the duff dries in the summer. They therefore require periodic wildfire to clear competing vegetation and soil humus before successful regeneration can occur. Without fire, shade-loving species will crowd out young sequoia seedlings, and sequoia seeds will not germinate. When fully grown, these trees typically require large amounts of water and are therefore often concentrated near streams. Squirrels, chipmunks, finches and sparrows consume the freshly sprouted seedlings, preventing their growth.
Fires also bring hot air high into the canopy via convection, which in turn dries and opens the cones. The subsequent release of large quantities of seeds coincides with the optimal postfire seedbed conditions. Loose ground ash may also act as a cover to protect the fallen seeds from ultraviolet radiation damage. Due to fire suppression efforts and livestock grazing during the early and mid-20th century, low-intensity fires no longer occurred naturally in many groves, and still do not occur in some groves today. The suppression of fires leads to ground fuel build-up and the dense growth of fire-sensitive white fir, which increases the risk of more intense fires that can use the firs as ladders to threaten mature giant sequoia crowns. Natural fires may also be important in keeping carpenter ants in check. In 1970, the National Park Service began controlled burns of its groves to correct these problems. Current policies also allow natural fires to burn. One of these untamed burns severely damaged the second-largest tree in the world, the Washington tree, in September 2003, 45 days after the fire started. This damage made it unable to withstand the snowstorm of January 2005, leading to the collapse of over half the trunk.
In addition to fire, two animal agents also assist giant sequoia seed release. The more significant of the two is a longhorn beetle (Phymatodes nitidus) that lays eggs on the cones, into which the larvae then bore holes. Reduction of the vascular water supply to the cone scales allows the cones to dry and open for the seeds to fall. Cones damaged by the beetles during the summer will slowly open over the next several months. Some research indicates many cones, particularly higher in the crowns, may need to be partially dried by beetle damage before fire can fully open them. The other agent is the Douglas squirrel (Tamiasciurus douglasi) that gnaws on the fleshy green scales of younger cones. The squirrels are active year-round, and some seeds are dislodged and dropped as the cone is eaten.
Discovery and namingEdit
The giant sequoia was well known to Native American tribes living in its area. Native American names for the species include wawona, toos-pung-ish and hea-mi-withic, the latter two in the language of the Tule River Tribe.
The first reference to the giant sequoia by Europeans is in 1833, in the diary of the explorer J. K. Leonard; the reference does not mention any locality, but his route would have taken him through the Calaveras Grove. Leonard's observation was not publicized. The next European to see the species was John M. Wooster, who carved his initials in the bark of the 'Hercules' tree in the Calaveras Grove in 1850; again, this observation received no publicity. Much more publicity was given to the "discovery" by Augustus T. Dowd of the Calaveras Grove in 1852, and this is commonly cited as the species' discovery by non-natives. The tree found by Dowd, christened the 'Discovery Tree', was felled in 1853.
The first scientific naming of the species was by John Lindley in December 1853, who named it Wellingtonia gigantea, without realizing this was an invalid name under the botanical code as the name Wellingtonia had already been used earlier for another unrelated plant (Wellingtonia arnottiana in the family Sabiaceae). The name "Wellingtonia" has persisted in England as a common name. The following year, Joseph Decaisne transferred it to the same genus as the coast redwood, naming it Sequoia gigantea, but again this name was invalid, having been applied earlier (in 1847, by Endlicher) to the coast redwood. The name Washingtonia californica was also applied to it by Winslow in 1854, though this too is invalid, belonging to the palm genus Washingtonia.
In 1907, it was placed by Carl Ernst Otto Kuntze in the otherwise fossil genus Steinhauera, but doubt as to whether the giant sequoia is related to the fossil originally so named makes this name invalid.
The nomenclatural oversights were finally corrected in 1939 by John Theodore Buchholz, who also pointed out the giant sequoia is distinct from the coast redwood at the genus level and coined the name Sequoiadendron giganteum for it.
The etymology of the genus name has been presumed—initially in The Yosemite Book by Josiah Whitney in 1868—to be in honor of Sequoyah (1767–1843), who was the inventor of the Cherokee syllabary. An etymological study published in 2012, however, concluded that the name was more likely to have originated from the Latin sequi (meaning to follow) since the number of seeds per cone in the newly classified genus fell in mathematical sequence with the other four genera in the suborder.
John Muir wrote of the species in about 1870:
"Do behold the King in his glory, King Sequoia! Behold! Behold! seems all I can say. Some time ago I left all for Sequoia and have been and am at his feet, fasting and praying for light, for is he not the greatest light in the woods, in the world? Where are such columns of sunshine, tangible, accessible, terrestrialized?'
Wood from mature giant sequoias is highly resistant to decay, but due to being fibrous and brittle, it is generally unsuitable for construction. From the 1880s through the 1920s, logging took place in many groves in spite of marginal commercial returns. The Hume-Bennett Lumber Company was the last to harvest giant sequoia, going out of business in 1924. Due to their weight and brittleness, trees would often shatter when they hit the ground, wasting much of the wood. Loggers attempted to cushion the impact by digging trenches and filling them with branches. Still, as little as 50% of the timber is estimated to have made it from groves to the mill. The wood was used mainly for shingles and fence posts, or even for matchsticks.
Pictures of the once majestic trees broken and abandoned in formerly pristine groves, and the thought of the giants put to such modest use, spurred the public outcry that caused most of the groves to be preserved as protected land. The public can visit an example of 1880s clear-cutting at Big Stump Grove near General Grant Grove. As late as the 1980s, some immature trees were logged in Sequoia National Forest, publicity of which helped lead to the creation of Giant Sequoia National Monument.
The wood from immature trees is less brittle, with recent tests on young plantation-grown trees showing it similar to coast redwood wood in quality. This is resulting in some interest in cultivating giant sequoia as a very high-yielding timber crop tree, both in California and also in parts of western Europe, where it may grow more efficiently than coast redwoods. In the northwest United States, some entrepreneurs have also begun growing giant sequoias for Christmas trees. Besides these attempts at tree farming, the principal economic uses for giant sequoia today are tourism and horticulture.
Formerly threatened through excess logging, sequoias are now threatened by both a combination of fire and fire suppression, along with drought and climate change. Fire suppression caused by European land management practices promotes the excessive growth of smaller trees such as fir, which can dry out in droughts, especially those fueled by climate change, and serve as a fuel load for devastating crown fires fueled by strong winds, which can kill large amounts of sequoias. One such fire, the Castle Fire of 2020, is thought to have wiped out almost 10-14% of the species' whole population, or 7500–10,600 mature trees, including potentially the King Arthur Tree, the 10th tallest known individual. 3 to 5% more, or 2,261-3,637 sequoias, are thought to have died during the KNP Complex and Windy Fire in 2021, with a combined total of 13 - 19%. The most effective remedy for these impacts is heavy prescribed burning, which will need to be multiplied by 30 times current burning practices in order to ensure heathy sequoia groves.
Giant sequoia is a very popular ornamental tree in many areas. It is successfully grown in most of western and southern Europe, the Pacific Northwest of North America north to southwest British Columbia, the southern United States, southeast Australia, New Zealand and central-southern Chile. It is also grown, though less successfully, in parts of eastern North America.
Trees can withstand temperatures of −31 °C (−25 °F) or colder for short periods of time, provided the ground around the roots is insulated with either heavy snow or mulch. Outside its natural range, the foliage can suffer from damaging windburn.
The tallest giant sequoia ever measured outside of the United States is a specimen planted near Ribeauvillé in France in 1856 and measured in 2014 at a height between 57.7 m (189 ft) and 58.1 m (191 ft) at age 158 years.
The giant sequoia was first brought into cultivation in Britain in 1853 by the horticulturist Patrick Matthew of Perthshire from seeds sent by his botanist son John in California. A much larger shipment of seed collected from the Calaveras Grove by William Lobb, acting for the Veitch Nursery near Exeter, arrived in England in December 1853; seed from this batch was widely distributed throughout Europe.
Growth in Britain is very fast, with the tallest tree, at Benmore in southwest Scotland, reaching 56.4 m (185 ft) in 2014 at age 150 years, and several others from 50–53 m (164–174 ft) tall; the stoutest is around 12 m (39 ft) in girth and 4 m (13 ft) in diameter, in Perthshire. The Royal Botanic Gardens at Kew in London also contains a large specimen. Biddulph Grange Garden in Staffordshire holds a fine collection of both Sequoiadendron giganteum and Sequoia sempervirens (coast redwood). The General Sherman of California has a volume of 1,489 m3 (52,600 cu ft); by way of comparison, the largest giant sequoias in Great Britain have volumes no greater than 90–100 m3 (3,200–3,500 cu ft), one example being the 90 m3 (3,200 cu ft) specimen in the New Forest.
Numerous giant sequoia were planted in Italy from 1860 through 1905. Several regions contain specimens that range from 40 to 48 metres (131 to 157 ft) in height. The largest tree is in Roccavione, in the Piedmont, with a basal circumference of 16 metres (52 ft). One notable tree survived a 200-metre (660 ft) tall flood wave in 1963 that was caused by a landslide at Vajont Dam. There are numerous giant sequoia in parks and reserves.
Growth rates in some areas of Europe are remarkable. One young tree in Italy reached 22 m (72 ft) tall and 88 cm (2.89 ft) trunk diameter in 17 years (Mitchell, 1972).
Northern and Central EuropeEdit
Growth further northeast in Europe is limited by winter cold. In Denmark, where extreme winters can reach −32 °C (−26 °F), the largest tree was 35 m (115 ft) tall and 1.7 m (5.6 ft) diameter in 1976 and is bigger today. One in Poland has purportedly survived temperatures down to −37 °C (−35 °F) with heavy snow cover.
United States and CanadaEdit
Giant sequoias are grown successfully in the Pacific Northwest and southern US, and less successfully in eastern North America. Giant sequoia cultivation is very successful in the Pacific Northwest from western Oregon north to southwest British Columbia, with fast growth rates. In Washington and Oregon, it is common to find giant sequoias that have been successfully planted in both urban and rural areas. In the Seattle area, large specimens exceeding 90 ft (27 m) are fairly common and exist in several city parks and many private yards (especially east Seattle including Capitol Hill, Washington Park, & Leschi/Madrona, as well as Tacoma's Jefferson Park).
In the northeastern US there has been some limited success in growing the species, but growth is much slower there, and it is prone to Cercospora and Kabatina fungal diseases due to the hot, humid summer climate there. A tree at Blithewold Gardens, in Bristol, Rhode Island, is reported to be 27 metres (89 ft) tall, reportedly the tallest in the New England states. The tree at the Tyler Arboretum in Delaware County, Pennsylvania, at 29.1 metres (95 ft) may be the tallest in the northeast. Specimens also grow in the Arnold Arboretum in Boston, Massachusetts (planted 1972, 18 m tall in 1998), at Longwood Gardens near Wilmington, Delaware, in the New Jersey State Botanical Garden at Skylands in Ringwood State Park, Ringwood, New Jersey, and in the Finger Lakes region of New York. Private plantings of giant sequoias around the Middle Atlantic States are not uncommon, and other publicly accessible specimens can be visited at the U.S. National Arboretum in Washington, D.C. A few trees have been established in Colorado as well. Additionally, numerous sequoias have been planted with success in the state of Michigan.
A cold-tolerant cultivar 'Hazel Smith' selected in about 1960 is proving more successful in the northeastern US. This clone was the sole survivor of several hundred seedlings grown at a nursery in New Jersey. The U.S. National Arboretum has a specimen grown from a cutting in 1970 that can be seen in the Gotelli Conifer Collection.
The Ballarat Botanical Gardens contain a significant collection, many of them about 150 years old. Jubilee Park and the Hepburn Mineral Springs Reserve in Daylesford, Cook Park in Orange, New South Wales and Carisbrook's Deep Creek park in Victoria both have specimens. Jamieson Township in the Victorian high country has two specimens which were planted in the early 1860s.
In Tasmania, specimens can be seen in private and public gardens, as sequoias were popular in the mid-Victorian era. The Westbury Village Green has mature specimens with more in Deloraine. The Tasmanian Arboretum contains both Sequoiadendron giganteum and Sequoia sempervirens specimens.
The Pialligo Redwood Forest consists of 3,000 surviving redwood specimens, of 122,000 planted, 500 meters east of the Canberra Airport. The forest was laid out by the city's designer Walter Burley Griffin, though the city's arborist, Thomas Charles Weston, advised against it. The National Arboretum Canberra began a grove of Sequoiadendron giganteum in 2008. They also grow in the abandoned arboretum at Mount Banda Banda in New South Wales.
Several impressive specimens of Sequoiadendron giganteum can be found in the South Island of New Zealand. Notable examples include a set of trees in a public park of Picton, as well as robust specimens in the public and botanical parks of Christchurch and Queenstown. There are also several in private gardens in Wanaka. Other locations in Christchurch and nearby include a number of mature trees at the Riccarton Park Racecourse, three large trees on the roadside bordering private properties on Clyde Road, near Wai-Iti Terrace—these are at least 150 years old. The suburb of ‘Redwood’ is named after a 160 years old Giant Redwood tree in the grounds of a local hotel. At St James Church, Harewood, is a protected very large specimen believed to be about 160 years old. A grove of about sixteen Redwood trees of varying ages is in Sheldon Park in the Belfast, New Zealand suburb. Some of these trees are in poor condition because of indifferent care. There is also a very large tree at Rangiora High School, which was planted for Queen Victoria's Golden Jubilee and is thus over 130 years old. Other Giant Redwood trees in Rangiora include mature specimens in Victoria Park, Rangiora Borough School and the street opposite, Lilybrook Reserve, and in the carpark of a supermarket in Ivory Street.
The location of a large number of New Zealand Redwoods can be found at https://register.notabletrees.org.nz
The best site to see Giant Redwoods in New Zealand is at Rotorua. The six hectare stand of Californian Redwoods is named the Redwood Memorial Grove and is protected from tree harvesting. Redwoods can also be found near Lake Rotokakahi (the Green Lake) and in various other spots within the forest. But none of them are as magnificent as those in the Redwood Memorial Grove. They were planted in the early 1900s as part of experiments to determine suitable trees for commercial growing in New Zealand.
Largest by trunk volumeEdit
Some sequoias, such as the Mother of the Forest, were undoubtedly far larger than any living tree today. However, as of 2009, the top ten largest giant sequoias sorted by volume of their trunks are:[note 1]
|Rank||Tree Name||Grove||Height||Girth at ground||Volume||Estimated Age|
|1||General Sherman||Giant Forest||275||84||103||31||52,508||1,486.9||2,300−2,700|
|2[note 2]||General Grant||General Grant Grove||268||82||108||33||46,608||1,319.8[note 2]||1,650|
|3[note 2]||President||Giant Forest||241||73||93||28||45,148||1,278.4[note 2]||3,200|
|5||Stagg||Alder Creek Grove||243||74||109||33||42,557||1,205.1||3,000|
|6||Boole||Converse Basin||269||82||113||34||42,472||1,202.7||2,000 (minimum)|
|7||Genesis||Mountain Home Grove||253||77||85||26||41,897||1,186.4|
|9||King Arthur||Garfield Grove||270||82||104||32||40,656||1,151.2|
- The General Sherman tree is estimated to weigh about 2100 tonnes.
- The Washington Tree was previously arguably the second largest tree with a volume of 47,850 cubic feet (1,355 m3) (although the upper half of its trunk was hollow, making the calculated volume debatable), but after losing the hollow upper half of its trunk in January 2005 following a fire, it is no longer of great size.
- Redwood – Redwood Mountain Grove – 95 metres (311 ft)
- tallest outside the United States: specimen near Ribeauvillé, France, measured in 2014 at a height between 58 m (190 ft) and 58 m (190 ft) at age 158 years.
- tallest planted outside the natural range: specimen in Oregon, US, measured 2020 at height 65 m (213 ft) by Certified Arborist. Estimated age 90–100 years.
- Waterfall Tree – Alder Creek Grove – 47 metres (155 ft) – tree with enormous basal buttress on very steep ground.
Greatest base diameterEdit
- Waterfall Tree – Alder Creek Grove – 21 metres (69 ft) – tree with enormous basal buttress on very steep ground.
- Tunnel Tree – Atwell Mill Grove – 17 metres (57 ft) – tree with a huge flared base that has burned all the way through.
Greatest mean diameter at breast heightEdit
- 0.9 metres (3 ft) or more
- Mother of the Forest
- General Sherman (tree)
- The House (trees)
- Bury Me in Redwood Country
- List of giant sequoia groves
- Sequoia National Park
- Kings Canyon National Park
- Yosemite National Park
- Calaveras Big Trees State Park
- Sequoia sempervirens – Coast Redwood
- Old growth forest
- List of superlative trees
- The volume figures have a low degree of accuracy (at best about ±14 cubic metres or 490 cubic feet), due to difficulties in measurement; stem diameter measurements are taken at a few set heights up the trunk, and assume that the trunk is circular in cross-section, and that taper between measurement points is even. The volume measurements also do not take cavities into account. The measurements are trunk-only, and do not include the volume of wood in the branches or roots.
- This table presents giant sequoias sorted by the volume of their trunks. In December 2012, Stephen Sillett announced a measurement of the President tree with a total of 54,000 cubic feet (1,500 m3) of wood and 9,000 cubic feet (250 m3) of wood in the branches. Ranked according to the total amount of wood in the tree, the General Sherman tree is first, the President tree is second, and the General Grant tree is third. General Sherman has 2,000 cubic feet (57 m3) more wood than the President tree.
- Schmid, R. & Farjon, A. (2013). "Sequoiadendron giganteum". IUCN Red List of Threatened Species. 2013: e.T34023A2840676.
- NatureServe. 2020. Sequoiadendron giganteum, Giant Sequoia. NatureServe, Arlington, Virginia. Available https://explorer.natureserve.org/Taxon/ELEMENT_GLOBAL.2.130747/Sequoiadendron_giganteum. Accessed 11 November 2021.
- "Sequoia and Kings Canyon brochure" (PDF). National Park Service. Archived (PDF) from the original on 2016-10-26. Retrieved 2016-10-26.
- "The Giant Sequoia National Monument". usda.gov. United States Department of Agriculture – Forest service. Archived from the original on November 19, 2018. Retrieved December 6, 2018.
- "2021 Fire Season Impacts to Giant Sequoias (U.S. National Park Service)". www.nps.gov. Retrieved 2021-11-20.
- Alexander, Kurtis (2021-06-04). "Super-hot California wildfire wiped out 10% of world's sequoia trees. Can they survive climate change?". San Francisco Chronicle. Retrieved 2021-06-04.
- Group), Aljos Farjon (IUCN SSC Conifer Specialist; Berkeley), Rudi Schmid (UC (2011-04-18). "IUCN Red List of Threatened Species: Sequoiadendron giganteum". IUCN Red List of Threatened Species. Retrieved 2021-06-04.
- Lowe, Gary D. (2012). "Endlicher's Sequence: The Naming of the Genus Sequoia" (PDF). cnps.org. California Native Plant Society. p. 27. Retrieved January 15, 2017.
Whitney states, 'The genus was named in honor of Sequoia* or Sequoyah, a Cherokee Indian.'
- Sierra Nevada – The Naturalist's Companion. University of California Press. 1 June 2000. p. 55. ISBN 978-0-520-92549-6.
- Lowe, Gary D. (2012). "Endlicher's Sequence: The Naming of the Genus Sequoia" (PDF). cnps.org. California Native Plant Society. p. 33. Retrieved January 15, 2017.
...the foregoing has shown that the name of the genus Sequoia as a tribute to the Cherokee linguist Sequoyah is an unsubstantiated opinion...Endlicher named the genus for the operation that he had conducted. The new genus fell in sequence with the other four genera in his suborder.
- Flint 2002
- Flint, Wendell D. (1987). To Find the Biggest Tree. Sequoia National Forest Association. p. 94.
- Vaden, M.D. "Coast Redwood Discovery. Sequoia sempervirens".
- H. Thomas Harvey, Evolution and History of Giant Sequoia. Presented at the Workshop on Management of Giant Sequoia, May 24–25, 1985, Reedley, California. Retrieved 2019-12-05.
- Yosemite National Park (U.S. National Park Service). "Sequoia Research". www.nps.gov. Retrieved 2019-12-05.
- Peattie, Donald Culross (1953). A Natural History of Western Trees. New York: Bonanza Books. p. 10.
- James E Eckenwalder. Conifers of the World, The Complete Reference. p. 586. Timber Press 2009. ISBN 978-0881929744
- Bryan G Bowes. Trees and Forests, a colour guide. pp. 48–49. Manson Publishing 2010. ISBN 978-1840760859
- Schmidt, Rudolf; Mena, Schmidt (2012). "Naturalization of Sequoiadendron giganteum (Cupressaceae) in Montane Southern California". Aliso: A Journal of Systematic and Evolutionary Biology. 30 (1): 19–32. doi:10.5642/ALISO.20123001.04. S2CID 84948955.
- Schmidt, Rudolf; Mena, Schmidt (2013). "Sequoiadendron giganteum (Cupressaceae) at Lake Fulmor, Riverside County, California". Aliso: A Journal of Systematic and Evolutionary Biology. 30 (2): 103–107 – via Scholarship @ Claremont.
- Masters, Nathan (21 May 2014). "These Sequoia Trees Are Thriving 175 Miles South of Their Natural Range". Gizmodo. Retrieved April 15, 2018.
- National Geographic Magazine December 2012
- "Giant Sequoias and Fire". Sequoia & Kings Canyon National Parks. National Park Service. Retrieved 2021-08-26.
- Peattie, Donald Culross (1953). A Natural History of Western Trees. New York: Bonanza Books. p. 11.
- Stephens, Scott; Finney, Mark (2002). "Prescribed fire mortality of Sierra Nevada mixed conifer tree species: effects of crown damage and forest floor combustion". Forest Ecology and Management. 162 (3): 261–271. doi:10.1016/S0378-1127(01)00521-7.
- Hartesveldt, RJ; Harvey, HT (1967). "The Fire Ecology of Sequoia Regeneration" (PDF). Tall Timbers Fire Ecology Conference. 7: 7.
- Farquhar, Francis P. (1925). "Discovery of the Sierra Nevada". California Historical Society Quarterly. 4 (1): 3–58. doi:10.2307/25177743. hdl:2027/mdp.39015049981668. JSTOR 25177743., Yosemite.ca.us
- Ornduff, R. (1994). "A Botanist's View of the Big Tree". In Aune, P. S. (ed.). Proceedings of the Symposium on Giant Sequoias (PDF). US Dept. of Agriculture Forest Service (Pacific Southwest Research Station). General Technical Report PSW-GTR-151.
- Muir, John (November 1996). Gifford, Terry (ed.). John Muir: His Life and Letters and Other Writings. Mountaineers Books. pp. 139–140. ISBN 0898864631.
- berkshireeagle.com / 'Giant Redwood Trees' will fall at Berkshire Museum despite interpretive value, Posted Saturday, June 30, 2018
- "Battle against Rough fire intensifies as blaze bears down on Hume Lake". fresnobee. Retrieved 2015-10-18.
- "Study: California fire killed 10% of world's giant sequoias". AP NEWS. 2021-06-02. Retrieved 2021-06-04.
- "Species Level Browse Results". NurseryGuide.com. Oregon Association of Nurseries. 2011. Archived from the original on 2012-03-09. Retrieved 2016-10-31.
- "The thickest, tallest, and oldest giant sequoia trees (Sequoiadendron giganteum)". monumentaltrees.com. Retrieved August 2, 2015.
- "Giant sequoia in the forêt domaniale de Ribeauvillé". monumentaltrees.com. Retrieved August 2, 2015.
- "Riquewihr/Ribeauvillé (68) : Forêt Domaniale de Ribeauvillé". Sequoias.eu. Retrieved August 2, 2015.
- "The History of Cluny – The Plant Collectors". clunyhousegardens.com. Retrieved 23 December 2008.
- Christopher J. Earle. "Sequoiadendron giganteum (Lindley) Buchholz 1939". University of Hamburg. Archived from the original on 2012-02-29. Retrieved 23 December 2008.
- Tree Register of the British Isles, tree-register.org
- "Top Trunks". Redwood World. Retrieved September 19, 2013.
- "RHS Plantfinder – Sequoiadendron giganteum". Retrieved 10 November 2018.
- "AGM Plants – Ornamental" (PDF). Royal Horticultural Society. July 2017. p. 96. Retrieved 10 November 2018.
- "Redwood World". Retrieved 14 May 2019.
- "Sequoie d'Italia". 4 August 2012. Retrieved January 22, 2014.
- Die Wiedereinführung des Mammutbaumes (Sequoiadendron giganteum) in die deutsche Forstwirtschaft. In: Mitteilungen der Deutschen Dendrologischen Gesellschaft. Vol. 75. pp. 57–75. Ulmer. Stuttgart 1984, ISBN 3-8001-8308-0
- Puzović, B. (August 15, 2011). "Lazarevac: Visoke sekvoje niču iz uglja" (in Serbian). Novosti.rs. Retrieved September 17, 2013.
- "Mansion and History". Blithewold Mansion, Gardens, and Arboretum.
- "Gardens". Blithewold Mansion, Gardens, and Arboretum.
- Big Trees Of Pennsylvania: Sequoiadendron – Giant Sequoia, pabigtrees.com
- "Colorado giant sequoia". giant-sequoia.com.
- "Michigan giant sequoia". Giant-sequoia.com.
- "A listing of species planted in the Tasmanian Arboretum". tasmanianarboretum.org.au. The Tasmanian Arboretum Inc. Retrieved 3 June 2019.
- "Pialligo Redwood Forest". VisitCanberra.com. Canberra and Region Visitors Centre. Retrieved 3 June 2019.
- "Pialligo Redwoods – FACTT – Canberra". sites.google.com. Retrieved 4 June 2019.
- "Forest 33 – Giant Sequoia". nationalarboretum.act.gov.au. National Arboretum Canberra. Retrieved 3 June 2019.
- "History". Rangiora High School.
- Cone, Tracie (2012-12-01). "Upon further review, giant sequoia tops a neighbor". Associated Press. Archived from the original on 2012-12-02.
- Quammen, David. "Giant Sequoias". National Geographic.
- Fry & White 1938 harvnb error: no target: CITEREFFryWhite1938 (help)
- "New Tallest Non-indigenous Sequoiadendron".
- Conifer Specialist Group (1998). "Sequoiadendron giganteum". IUCN Red List of Threatened Species. 1998. Retrieved 11 May 2006.old-form url Listed as Vulnerable (VU A1cd v2.3)
- Aune, P. S., ed. (1994). Proceedings of the Symposium on Giant Sequoias. US Dept. of Agriculture Forest Service (Pacific Southwest Research Station). General Technical Report PSW-GTR-151.
- Flint, W.D. (2002). To Find The Biggest Tree. Sequoia Natural History Association, Inc. ISBN 1-878441-09-4.
- Mitchell, Alan (1972). Conifers in the British Isles. HMSO. Forestry Commission Booklet 33.
- Mitchell, Alan (1996). Alan Mitchell's Trees of Britain. HarperCollins. ISBN 0-00-219972-6.
- Harvey, H. T.; Shellhammer, H. S.; Stecker, R. E. (1980). Giant sequoia ecology. Scientific Monograph Series. 12. Washington, DC: U.S. National Park Service.
- Kilgore, B. (1970). "Restoring Fire to the Sequoias". National Parks and Conservation Magazine. 44 (277): 16–22.
- Zsolt Debreczy; Istvan Racz (2012). Kathy Musial (ed.). Conifers Around the World (1st ed.). DendroPress. p. 1089. ISBN 978-9632190617.
- Chase, J. Smeaton (1911). "Sequoia gigantea, Also called S. washingtoniana or S. wellingtonia (Big-tree, Sequoia, Redwood)". Cone-bearing Trees of the California Mountains. Eytel, Carl (illustrations). Chicago: A.C. McClurg & Co. pp. 88–90. LCCN 11004975. OCLC 3477527.
- Earle, Christopher J., ed. (2018). "Sequoiadendron giganteum". The Gymnosperm Database.
- Habeck, R. J. (1992). "Sequoiadendron giganteum". Fire Effects Information System (FEIS). US Department of Agriculture (USDA), Forest Service (USFS), Rocky Mountain Research Station, Fire Sciences Laboratory – via https://www.feis-crs.org/feis/.
- Hartesveldt, Richard J.; Harvey, H. Thomas; Shellhammer, Howard S.; Stecker, Ronald E. (1975). The Giant Sequoia of the Sierra Nevada. Washington, D.C.: National Park Service.
- ARKive: Sequoiadendron giganteum, arkive.org
- Arboretum de Villardebelle – photos of cones & shoots with phenology notes, pinetum.org
- Giant Sequoia Fire History in Mariposa Grove, Yosemite National Park, nps.gov
- Save-the-Redwoods League, savethewoods.org
- "Sequoias of Yosemite National Park" 1949 by James W. McFarland
- Redwoodworld.co.uk giant redwoods in the U.K.
- Scenes of Wonder and Curiosity in California (1862) – The Mammoth Trees Of Calaveras, yosemite.ca.us
- Short radio episode Woody Gospel Letter in which John Muir extols "King Sequoia" from The Life and Letters of John Muir, 1924. California Legacy Project.
- Encyclopædia Britannica (11th ed.). 1911. .
- Conifers Around the World: Sequoiadendron giganteum – Giant Sequoia.
- Giants of Sequoia and Kings Canyon National Park, On YouTube by Sequoia Parks Conservancy
- on YouTube