1. Family: Cupressaceae Gray
    1. Genus: Sequoiadendron J.Buchholz
      1. Sequoiadendron giganteum (Lindl.) J.Buchholz

        It may not be the tallest tree in the world but Sequoiadendron giganteum is the largest by volume, reaching up to 95 m in height and 12 m in diameter. On its introduction to Britain in 1853, the species was named Wellingtonia gigantea after the recently deceased Duke of Wellington. However, this scientific name was not legitimate because the name Wellingtonia had been used earlier for another plant (although it is still called Wellingtonia as a common name in the UK).

    [KSP]
    General Description
    Giant by name and giant by nature, this huge Californian conifer is by volume the largest tree in the world.

    It may not be the tallest tree in the world but Sequoiadendron giganteum is the largest by volume, reaching up to 95 m in height and 12 m in diameter. On its introduction to Britain in 1853, the species was named Wellingtonia gigantea after the recently deceased Duke of Wellington. However, this scientific name was not legitimate because the name Wellingtonia had been used earlier for another plant (although it is still called Wellingtonia as a common name in the UK).

    Always on the lookout for new and exciting large trees, estate owners jumped at the chance of growing another impressive specimen and having the name Wellingtonia worked wonders as a marketing tool. Although planted less frequently now, it is quite common throughout the British Isles, particularly in large gardens and parks. The giant redwood, which can live up to 3,200 years, was formerly put in the swamp cypress family (Taxodiaceae), which is now placed in the cypress family (Cupressaceae).

    Species Profile

    Geography and distribution

    Native to California in the United States, the giant redwood is found on the western slopes of the Sierra Nevada mountain range, where it occurs in about 75 distinct groves. It inhabits mixed conifer forests at 1,100 - 1,500 m above sea level.

    Description

    An evergreen tree with distinctive spongy red bark, the giant redwood can reach up to 95 m in height and 12 m in diameter. The deeply furrowed bark can be up to 60 cm thick. The branches form a rounded crown towards the top with individual branches sweeping downwards with upturned ends. The leaves are small and scale-like and are in spirals. Male and female cones are borne on the same tree, and are tiny in relation to the tree as a whole, the female ones measuring a mere 5-7 cm. The cones take at least two years to ripen; however, many cones remain green and unopened for anything up to 20 years. They are reddish-brown when mature and contain numerous, flattened, winged seeds.

    Reproduction of the giant redwood

    Natural bush fires are not as common as they once were in California, but are essential for giant redwood reproduction. The bark is fire-resistant, so the tree is left unharmed after a fire while other plant life around it is cleared. This is a prerequisite for seedlings to grow, helped along by a layer of ash as a seedbed. The heat from the fire also starts the process, as it causes the cones to open, dispersing their seeds on the wind.

    Giant by name...

    The largest living specimens are found in its native California, where the largest tree is known as ‘General Sherman’. At the last measurement, it stood 84 m (275 ft) high, with a trunk circumference of 31 m (103 ft) at ground level. It is estimated to be around 3,200 years old.

    The speed at which Sequoiadendron giganteum grows when young is nothing short of phenomenal. In Italy, a young tree reached a height of 22 m (72 ft) in just 17 years. Growth rates depend largely on the habitat and weather conditions, and while the tree can survive in temperatures as low as -30°C, it tends to flourish in a humid environment with dry summers and snowy winters.

    Threats and conservation

    The giant redwood has been rated as Vulnerable (VU) according to IUCN Red List criteria, populations having been reduced as a result of large-scale logging between 1856 and 1955. Measures taken to prevent bush fires also led to a build-up of undergrowth which may have reduced the growth of seedlings, which need a clearing to thrive. The majority of giant redwoods is now within National Parks (such as Yosemite, Sequoia and Kings Canyon); indeed 90% of wild populations are now protected. Land management and tree-planting schemes have been put in place to conserve the species.

    Uses

    Apart from being fire-resistant, the timber of Sequoiadendron giganteum has little commercial value, which makes the widespread felling of this tree during the nineteenth and twentieth centuries all the more unfortunate. The magnificent giant redwood is now a major draw for ecotourists from around the world, and it is seen as one of the flagship species for conservation in the United States. It has been widely planted as an ornamental tree in large parks and gardens in countries with a temperate climate, from Europe to New Zealand, and Canada to Chile.

    Millennium Seed Bank: Seed storage

    Kew's Millennium Seed Bank Partnership aims to save plant life world wide, focusing on plants under threat and those of most use in the future. Seeds are dried, packaged and stored at a sub-zero temperature in our seed bank vault.

    Description of seeds:Average 1,000 seed weight = 6.6 gNumber of seed collections stored in the Millennium Seed Bank:One

    Giant redwood at Kew

    The giant redwood can be seen growing in Redwood Grove, about halfway between the Pagoda and the River Thames at Kew, and can also be viewed from the Rhizotron and Xstrata Treetop Walkway. 

    Christmas Tree at Wakehurst

    During the winter you may also be able to enjoy the spectacle of England’s largest growing Christmas tree, a towering 113-foot giant redwood, which is illuminated daily in front of the Mansion at Wakehurst, Kew’s country estate in West Sussex.

    Each year a team of expert tree-climbers from Wakehurst’s woodland and conservation team spend a day, using ropes and specialist climbing gear, festooning a 113-foot giant redwood tree with 1,800 Christmas lights. The twinkling Christmas tree is a local landmark that can be seen for miles around – even from the air by pilots approaching nearby Gatwick Airport.

    Distribution
    USA
    Ecology
    Growing as an emergent in mixed montane conifer forests.
    Conservation
    Vulnerable (VU) according to IUCN Red List criteria.
    Hazards

    None known.

    Images

    Distribution

    Found In:

    California

    Introduced Into:

    Austria, France

    Common Names

    English
    Giant redwood

    Sequoiadendron giganteum (Lindl.) J.Buchholz appears in other Kew resources:

    Date Identified Reference Herbarium Specimen Type Status
    Jun 1, 2012 Goldman, D.H. [2920], USA K000554703
    Nov 1, 2000 Bracelin, H.P. [717] K000088887
    Feb 24, 2000 Lobb, W. [436], California K000088885 isotype
    Feb 1, 2000 Kuntze, O. [3169] K000088886
    Feb 1, 2000 Stagner, H. [s.n.] K000088888
    Feb 1, 2000 Thomas, J.H. [10390] K000088889
    73846.000
    73847.000
    73848.000

    First published in Amer. J. Bot. 26: 536 (1939)

    Accepted in:

    • [2] Farjon, A. (2010) A handbook of the world's Conifers 2: 533-1111. BRILL, Leiden, Boston.
    • [4] Farjon, A. (2001) World Checklist and Bibliography of Conifers , ed. 2: 1-309. The Royal Botanic Gardens, Kew.
    • [6] Tutin, T.G. & al. (eds.) (1993) Flora Europaea ed. 2, 1: 1-581. Cambridge University Press.

    Literature

    • [1] Farjon, A. (2010). A Handbook of the World’s Conifers. E.J. Brill, Leiden & Boston.
    • [3] Farjon, A. (2005). A Monograph of Cupressaceae and Sciadopitys. Royal Botanic Gardens, Kew.
    • [5] Conifer Specialist Group (1998). Sequoiadendron giganteum. In: IUCN 2010. IUCN Red List of Threatened Species. Version 2010.3. <www.iucnredlist.org>. Downloaded on 26 October 2010.

    Sources

    International Plant Names Index
    The International Plant Names Index (2016). Published on the Internet http://www.ipni.org
    [A] © Copyright 2016 International Plant Names Index. https://creativecommons.org/licenses/by/3.0

    Kew Species Profiles
    Kew Species Profiles
    [B] http://creativecommons.org/licenses/by-nc-sa/3.0
    [C]

    World Checklist of Selected Plant Families
    World Checklist of Selected Plant Families(2016). Published on the Internet http://apps.kew.org/wcsp/
    [D] See http://kew.org/about-kew/website-information/legal-notices/index.htm You may use data on these Terms and Conditions and on further condition that: The data is not used for commercial purposes; You may copy and retain data solely for scholarly, educational or research purposes; You may not publish our data, except for small extracts provided for illustrative purposes and duly acknowledged; You acknowledge the source of the data by the words "With the permission of the Trustees of the Royal Botanic Gardens, Kew" in a position which is reasonably prominent in view of your use of the data; Any other use of data or any other content from this website may only be made with our prior written agreement. http://creativecommons.org/licenses/by-nc-sa/3.0
    [E] © Copyright 2016 International Plant Names Index and World Checkist of Selected Plant Families. https://creativecommons.org/licenses/by/3.0
    [F] © Copyright 2017 International Plant Names Index and World Checkist of Selected Plant Families. http://creativecommons.org/licenses/by/3.0