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Overview

Brief Summary

Description

The giant sequoia is world-renowned as the largest living thing on the planet, and these majestic trees continue to inspire wonder. Although not the tallest trees, their sheer volume, with the possible exception of colonial organisms such as corals, make giant sequoias the largest living things on earth (3). Also known as 'big tree' in California, the giant sequoia lives up to its name, reaching up to 95 m in height and 11 m in diameter (2). The massive, tapering trunk is a characteristic reddish-brown colour; the bark is extremely thick, sometimes up to 60 cm, and deeply furrowed (4). In mature trees the first half of the trunk is clear of branches, they form a rounded crown towards the top with individual branches sweeping downward with upturned ends (3). The small, scale-like leaves are green and spirally arranged (4). Both male and female cones are carried on the same tree; female cones are up to 7.5 cm long and 4 cm wide, composed of spirally arranged scales. They are reddish-brown when mature and contain numerous, flattened, winged seeds (4).
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Biology

Giant sequoias take around 20 years to reach maturity and start bearing cones, and the oldest known individuals are over 3,000 years old (2). Pollination occurs between December and May and cones develop during the spring and summer months (4). Seeds are only released as the cones dry out, shrinking and thus revealing gaps from which the seeds can fall; the process is therefore dependent on particular conditions and cones can lay dormant for many years (5). Each cone contains roughly 230 seeds and each tree will have around 11,000 cones at any one time; these tiny winged seeds are dispersed away from their parent tree by the wind, insects and rodents (2). The germination of seeds is, however, also dependent on particular conditions and these tiny, thin seeds require highly favourable soils with no overlying vegetation into which they can bury easily (4). As with other long-lived trees, fire seems to pay an important role in the life of a giant sequoia. A relatively high frequency of low intensity fires helps to rid the area of competitors whilst providing rich soils for the germination of seedlings. The heat generated by fires also helps to dry out the cones and open them. Mature trees are fairly indestructible, the loosely packed fibres in the thick bark are very poor conductors of fire (3).
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Taxodiaceae -- Redwood family

    C. Phillip Weatherspoon

    Since its discovery in the mid-nineteenth century, giant sequoia (Sequoiadendron  giganteum), also called sequoia, bigtree, and Sierra redwood, has been  noted for its enormous size and age, and its rugged, awe-inspiring beauty.  Because the species has broad public appeal and a restricted natural  range, most groves of giant sequoia have been accorded protected status.  Outside its natural range, both in the United States and in many other  countries, giant sequoia is highly regarded as an ornamental and shows  promise as a major timber-producing species.

  • Burns, Russell M., and Barbara H. Honkala, technical coordinators. 1990. Silvics of North America: 1. Conifers; 2. Hardwoods.   Agriculture Handbook 654 (Supersedes Agriculture Handbook 271,Silvics of Forest Trees of the United States, 1965).   U.S. Department of Agriculture, Forest Service, Washington, DC. vol.2, 877 pp.   http://www.na.fs.fed.us/spfo/pubs/silvics_manual/table_of_contents.htm External link.
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C. Phillip Weatherspoon

Source: Silvics of North America

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Distribution

Range

The giant sequoia is found on the western slopes of the Sierra Nevada mountain range, California, United States (4). Today the range is much more discontinuous than it once was, and the species is restricted to around 75 distinct groves (2).
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National Distribution

United States

Origin: Native

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

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Occurrence in North America

     CA  HI

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More info for the term: natural

The natural distribution of giant sequoia is restricted to about 75
groves, comprising a total area of only 35,607 acres (14,416 ha) along a
limited area of the western Sierra Nevada, California.  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 groves are concentrated between the Kings River and the Deer
Creek Grove in southern Tulare County [10,28].  Groves range in size
from approximately 2,470 acres (1,000 ha) with 20,000 giant sequoias to
small groves with only six living trees [24].
  • 10.  Hartesveldt, Richard J.; Harvey, H. Thomas; Shellhammer, Howard S.;        Stecker, Ronald E. 1975. The sequoia of the Sierra Nevada. Washington,        DC: U.S. Department of the Interior, National Park Service. 180 p.        [4233]
  • 24.  Rundel, Philip W.; Parsons, David J.; Gordon, Donald T. 1977. Montane        and subalpine vegetation of the Sierra Nevada and Cascade Ranges. In:        Barbour, Michael G.; Major, Jack, eds. Terrestrial vegetation of        California. New York: John Wiley & Sons: 559-599.  [4235]
  • 28.  Weatherspoon, C. Philip. 1990. Sequoiadendron giganteum (Lindl.)        Buchholz. In: Burns, Russell M.; Honkala, Barbara H., technical        coordinators. Silvics of North America. Volume 1. Conifers. Agric.        Handb. 654. Washington, DC: U.S. Department of Agriculture, Forest        Service: 552-562.  [13415]

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Regional Distribution in the Western United States

More info on this topic.

This species can be found in the following regions of the western United States (according to the Bureau of Land Management classification of Physiographic Regions of the western United States):

   4  Sierra Mountains

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The natural range of giant sequoia is restricted to about 75 groves  scattered over a 420-km (260-mi) belt, nowhere more than about 24 km (15  mi) wide, extending along the west slope of the Sierra Nevada in central  California (16). The northern two-thirds of the range, from the  American River in Placer County southward to the Kings River, takes in  only eight widely disjunct groves. The remaining groves, including all the  large ones, are concentrated between the Kings River and the Deer Creek  Grove in southern Tulare County (33). Varying in size from less  than 1 to 1619 ha (1 to 4,000 acres), the groves occupy a total area of 14  410 ha (35,607 acres) (17).

     
- The native range of giant sequoia.


  • Burns, Russell M., and Barbara H. Honkala, technical coordinators. 1990. Silvics of North America: 1. Conifers; 2. Hardwoods.   Agriculture Handbook 654 (Supersedes Agriculture Handbook 271,Silvics of Forest Trees of the United States, 1965).   U.S. Department of Agriculture, Forest Service, Washington, DC. vol.2, 877 pp.   http://www.na.fs.fed.us/spfo/pubs/silvics_manual/table_of_contents.htm External link.
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C. Phillip Weatherspoon

Source: Silvics of North America

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Calif.
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Physical Description

Morphology

Description

More info for the term: serotinous

Giant sequoias grow to an average height of 250 to 275 feet (76-84 m)
and 15 to 20 feet (5-7 m) d.b.h.  Record trees have been reported to be
310 feet (95 m) in height and 35 feet (11 m) d.b.h.  The leaves are
awl-shaped, sessile, and persistent.  Seed cones are 2 to 3 inches (5-8
cm) long, serotinous, persistent, and may remain green up to 20 years.
Bark is fibrous, furrowed, and may be 2 feet (0.6 m) thick at the base
of the columnar trunk [6,10].  The oldest known giant sequoia based on
ring count is 3,200 years old [10].
  • 10.  Hartesveldt, Richard J.; Harvey, H. Thomas; Shellhammer, Howard S.;        Stecker, Ronald E. 1975. The sequoia of the Sierra Nevada. Washington,        DC: U.S. Department of the Interior, National Park Service. 180 p.        [4233]
  • 6.  Brockman, C. Frank. 1979. Trees of North America. New York: Golden        Press. 280 p.  [16867]

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Description

Trees to 90 m tall; trunk strongly buttressed at base, to 12 m d.b.h.; bark brown, spongy, deeply fissured and finally separating into cinnamon-colored fibers; crown conical when young,

becoming open with age; branches of young trees spreading, on older trees drooping; axis of branchlets green or dark green in 1st year, thereafter pale brown to reddish brown. Leaves blue-green, base decurrent, distal free portion 3-5 mm, apex sharply pointed. Seed cones ellipsoid, 5-8 × 3-5.5 cm; cone scales shieldlike, ca. 2.5 cm, apical scales 6-10 mm wide, with distal groove, ending in a long, terete spine at middle when young. Seeds pale brown, elongate-ellipsoid, 3-6 mm.

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Physical Description

Tree, Very large tree more than 75 m tall, Evergreen, Monoecious, Habit erect, Trees without or rarely having knees, Tree with bark rough or scaly, Tree with bark very thick, up to 60 cm, Young shoots 3-dimensional, Buds not resinous, Leaves needle-like, Leaves scale-like, Leaves alternate, Needle-like leaf margins entire (use magnification), Leaf apex acute, Leaves < 5 cm long, Leaves < 10 cm long, Leaves not blue-green, Scale leaves without raised glands, Needle-like leaves not twisted, Needle-like leaf habit erect, Needle-like leaf habit drooping, Needle-like leaf sheath early deciduous, Needle-like leaf sheath persistent, Twigs glabrous, Twigs not viscid, Twigs without peg-like projections or large fascicles after needles fall, Berry-like cones orange, Woody seed cones < 5 cm long, Woody seed cones > 5 cm long, Bracts of seed cone included, Seeds tan, Seeds brown, Seeds winged, Seeds equally winged, Seed wings narrower than body.
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Stephen C. Meyers

Source: USDA NRCS PLANTS Database

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Description

Trees to 90 m; trunk to 11 m diam.; crown conic and monopodial when young, narrowed and somewhat rounded in age. Bark reddish brown, to ca. 60 cm thick, fibrous, ridged and furrowed. Branches generally horizontal to downward-sweeping with upturned ends. Leaves generally with stomates on both surfaces, the free portion to ca. 15 mm. Pollen cones nearly globose to ovoid, 4--8 mm. Seed cones 4--9 cm. Seeds 3--6 mm. 2 n = 22.
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Diagnostic Description

Synonym

Wellingtonia gigantea Lindley, Gard. Chron. 1853: 823. 1853; Sequoia gigantea (Lindley) Decaisne (1854), not Endlicher (1847).
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Synonym

Wellingtonia gigantea Lindley, Gard. Chron. 10: 823. 1853; Sequoia gigantea (Lindley) Decaisne 1854, not Endlicher 1847
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Ecology

Habitat

Habitat and Ecology

Habitat and Ecology
This species is forming 'groves' of a few to over 20,000 individuals in the Mixed Conifer Forest belt on the western slopes of the Sierra Nevada. It is mixed with other conifers: Abies concolor, A. magnifica, Calocedrus decurrens, Pinus lambertiana, P. ponderosa, P. jeffreyi, Pseudotsuga menziesii, Taxus brevifolia, and with fewer broad-leaved trees: Quercus kelloggii, Q. chrysolepis, Cornus nuttallii, Alnus rhombifolia, Salix scoulerana, Acer macrophyllum, and shrubs: Castanopsis sempervirens, Ceanothus cordulatus, C. parvifolius, C. integerrimus, Arctostaphylos patula, etc. The relatively narrow altitudinal belt, (830-)1,400-2,150(-2,700) m a.s.l., and the scattered concentration of groves, which tend to become smaller and further apart going north, indicate rather narrow climatic and soil conditions that are optimal in its natural habitat. Most groves are on granite-based residual and alluvial soils, some on glacial outwash, and mildly acidic; best growth is on deep, well-drained sandy loams with available ground water, the latter appears to be an important limiting factor. The climate is humid, with mostly autumn rain and winter snow, and dry summers, with mean annual precipitation between 900-1,400 mm, but with high year-to-year variation. Temperature in winter is mild, with light frosts but occasional extremes, and warm, occasionally hot, in summer. Sequoiadendron giganteum is well adapted to low-intensity forest fires (extremely thick bark) and resists windfall exceptionally well; its wood is also rot-resistant. As a result its longevity ranges from 2,000-3,000(-3,200) years.

Systems
  • Terrestrial
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Habitat characteristics

More info for the terms: density, frequency, mesic, natural

Low temperatures seem to be the limiting factor for giant sequoia at the
upper elevational limits of its range, as well as in areas with severe
winters where the species has been introduced.  Distribution of giant
sequoia at lower elevations appears to be restricted to sites with
available soil moisture throughout the summer drought period [24,28].

Climate:  Giant sequoia is found in a humid climate characterized by dry
summers.  Mean annual precipitation varies from 35 to 55 inches (88-138
cm).  Most precipitation comes in the form of snow between October and
April.  Mean annual snowfall ranges from 144 to 197 inches (360-493 cm),
and snow depths of 6.6 feet (2 m) or greater are common.  Mean daily
maximum temperatures for July are typically 75 to 84 degrees Fahrenheit
(24-29 deg C).  Mean minimum temperatures for January vary from 34 to 21
degrees Fahrenheit (1 to -6 deg C) [28].

Soils and topography:  Most giant sequoia groves are on granitic-based
residual and alluvial soils.  Some groves are on glacial outwash from
granite.  Other common parent materials include schistose, dioritic and
andesitic rocks.  Giant sequoia grows best in deep, well-drained sandy
loams.  It occurs with higher frequency on mesic sites, such as drainage
bottoms and meadow edges.  Soil pH ranges from 5.5 to 7.5, with an
average of about 6.5.  Long-term site occupancy develops soil of high
fertility, good base status, and low bulk density.  Except for its
moisture content, soil typically plays only a minor role in influencing
the distribution of the species [28].

Elevation:  Elevation of the giant sequoia groves generally range from
4,590 to 6,560 feet (1,400-2,000 m) in the north, and 5,580 to 7,050
(1,700-2,150 m) to the south.  The lowest natural occurrence of the
species is 2,720 feet (830 m) and the highest is 8,860 feet (2,700 m).
Giant sequoia generally appears on southern slopes in its northern
distribution and on more northerly slopes in the south [28].
  • 24.  Rundel, Philip W.; Parsons, David J.; Gordon, Donald T. 1977. Montane        and subalpine vegetation of the Sierra Nevada and Cascade Ranges. In:        Barbour, Michael G.; Major, Jack, eds. Terrestrial vegetation of        California. New York: John Wiley & Sons: 559-599.  [4235]
  • 28.  Weatherspoon, C. Philip. 1990. Sequoiadendron giganteum (Lindl.)        Buchholz. In: Burns, Russell M.; Honkala, Barbara H., technical        coordinators. Silvics of North America. Volume 1. Conifers. Agric.        Handb. 654. Washington, DC: U.S. Department of Agriculture, Forest        Service: 552-562.  [13415]

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Key Plant Community Associations

More info for the terms: mesic, natural, shrub

Giant sequoia principally occurs in scattered groves.  Nowhere does it
grow in pure stands, although in a few small areas stands do approach a
pure condition [28].  Although the giant sequoia groves of the central
and southern Sierra Nevada represent only a specific mesic segregate of
typical white fir (Abies concolor) forest communities, these groves are
often given special community recognition.  Only giant sequoia is
restricted to the groves [24].

Typically, giant sequoia is found in a mixed conifer type dominated by
California white fir (A. concolor var. lowiana).  Characteristic
associates include sugar pine (Pinus lambertiana), Jeffrey pine (P.
jeffreyi), ponderosa pine (P. ponderosa), Douglas-fir (Pseudotsuga
menziesii), incense-cedar (Calocedrus decurrens), and California black
oak (Quercus kelloggii).  Shrub types include bush chinkapin
(Castanopsis sempervirens) and mountain whitethorn (Ceanothus
cordulatus) [10,14,28].

Giant sequoia as a dominant species in the following typings:

Terrestrial natural communities of California [29]
Montane and subalpine vegetation of the Sierra Nevada and Cascade Ranges [24]
  • 10.  Hartesveldt, Richard J.; Harvey, H. Thomas; Shellhammer, Howard S.;        Stecker, Ronald E. 1975. The sequoia of the Sierra Nevada. Washington,        DC: U.S. Department of the Interior, National Park Service. 180 p.        [4233]
  • 14.  Kilgore, Bruce M. 1972. Fire's role in a Sequoia forest. Naturalist.        23(1): 26-37.  [8783]
  • 24.  Rundel, Philip W.; Parsons, David J.; Gordon, Donald T. 1977. Montane        and subalpine vegetation of the Sierra Nevada and Cascade Ranges. In:        Barbour, Michael G.; Major, Jack, eds. Terrestrial vegetation of        California. New York: John Wiley & Sons: 559-599.  [4235]
  • 28.  Weatherspoon, C. Philip. 1990. Sequoiadendron giganteum (Lindl.)        Buchholz. In: Burns, Russell M.; Honkala, Barbara H., technical        coordinators. Silvics of North America. Volume 1. Conifers. Agric.        Handb. 654. Washington, DC: U.S. Department of Agriculture, Forest        Service: 552-562.  [13415]
  • 29.  Holland, Robert F. 1986. Preliminary descriptions of the terrestrial        natural communities of California. Sacramento, CA: California Department        of Fish and Game. 156 p.  [12756]

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Habitat: Ecosystem

More info on this topic.

This species is known to occur in the following ecosystem types (as named by the U.S. Forest Service in their Forest and Range Ecosystem [FRES] Type classification):

   FRES21  Ponderosa pine
   FRES23  Fir - spruce
   FRES28  Western hardwoods

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Habitat: Cover Types

More info on this topic.

This species is known to occur in association with the following cover types (as classified by the Society of American Foresters):

   243  Sierra Nevada mixed conifer

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Habitat: Plant Associations

More info on this topic.

This species is known to occur in association with the following plant community types (as classified by Küchler 1964):

   K005  Mixed conifer forest

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Soils and Topography

Soils are derived from a variety of rock types. Most groves are on  granitic-based residual and alluvial soils, and three are on glacial  outwash from granite. Schistose, dioritic, and andesitic rocks also are  common parent materials (16,36).

    Typical soil series are Dome, Shaver, Holland, and Chaix. Characteristic  soil families are coarse-loamy, mixed, mesic Dystric Xerochrepts;  coarse-loamy, mixed, mesic Entic (and Typic) Xerumbrepts of the order  Inceptisols; and fine-loamy, mixed, mesic Ultic Haploxeralfs of the order  Alfisols. The natural range of the species lies mostly within the mesic  temperature regime, extending only a short distance into the frigid  regime, and wholly within the xeric moisture regime (22).

    Giant sequoia grows best in deep, well-drained sandy loams. Its density  also is much greater in the more mesic sites, such as drainage bottoms and  meadow edges, than in other habitats within a grove. Total acreage of  these productive sites is small, however. Relatively shallow and rocky  soils support vigorous individuals, some large, wherever the trees can  become established and where underground water is available to maintain  them (16,32).

    Soil pH ranges mostly from 5.5 to 7.5, with an average of about 6.5 (22).  Long-term site occupancy by giant sequoia appears to develop a soil of  high fertility, good base status, and low bulk density (40).

    Adequate soil moisture throughout the dry growing season is critical for  successful establishment of giant sequoia regeneration, although seedlings  do not survive in wet soils (36). One study has shown more  available soil moisture within a grove, possibly associated with  subterranean flow from higher elevations, than in adjacent forested areas  (34). Except for its moisture content, soil apparently plays only  a minor role in influencing the distribution of the species, as evidenced  by the considerable variability in parent material among groves and the  fact that giant sequoia grows vigorously when planted in diverse soils  around the world (16).

    Elevations of the groves generally range from 1400 to 2000 m (4,590 to  6,560 ft) in the north, and 1700 to 2150 m (5,580 to 7,050 ft) in the  south. The lowest natural occurrence of the species is 830 m (2,720 ft)  and the highest is 2700 m (8,860 ft). The eight northern groves are all on  slopes of a generally southern aspect. Between the Kings River and the  southern boundary of Sequoia National Park, groves appear on north and  south slopes with about equal frequency. Farther south, aspects are  predominantly northerly (32).

  • Burns, Russell M., and Barbara H. Honkala, technical coordinators. 1990. Silvics of North America: 1. Conifers; 2. Hardwoods.   Agriculture Handbook 654 (Supersedes Agriculture Handbook 271,Silvics of Forest Trees of the United States, 1965).   U.S. Department of Agriculture, Forest Service, Washington, DC. vol.2, 877 pp.   http://www.na.fs.fed.us/spfo/pubs/silvics_manual/table_of_contents.htm External link.
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C. Phillip Weatherspoon

Source: Silvics of North America

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Climate

Giant sequoia is found in a humid climate characterized by dry summers.  Mean annual precipitation in the groves varies from about 900 to 1400 mm  (35 to 55 in), with high year-to-year variation. Less than 30 mm. (1.2 in)  usually falls between June 1 and September 30. Most of the precipitation  comes in the form of snow between October and April. Mean annual snowfall  ranges from 366 to 500 cm (144 to 197 in), and snow depths of 2.0 m (6.6  ft) or greater are common in midwinter (32).

    Mean daily maximum temperatures for July for typical groves are 24°  to 29° C (75° to 84° F). Mean minimum temperatures for  January vary from 1° to -6° C (34° to 21° F). Extremes  are about -24° and 40° C (-12° and 104° F) (32,37).

    Low temperatures seem to be a limiting factor for giant sequoia at the  upper elevational limits of its range, as well as in areas with severe  winters where the species has been introduced. Distribution of the species  at low elevations is limited mainly by deficient soil moisture during the  growing season (34).

  • Burns, Russell M., and Barbara H. Honkala, technical coordinators. 1990. Silvics of North America: 1. Conifers; 2. Hardwoods.   Agriculture Handbook 654 (Supersedes Agriculture Handbook 271,Silvics of Forest Trees of the United States, 1965).   U.S. Department of Agriculture, Forest Service, Washington, DC. vol.2, 877 pp.   http://www.na.fs.fed.us/spfo/pubs/silvics_manual/table_of_contents.htm External link.
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C. Phillip Weatherspoon

Source: Silvics of North America

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Mixed montane coniferous forests, in isolated groves on the w slopes of the Sierra Nevada; 900--2700m.
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Inhabits mixed conifer woodlands, which are dominated by the California white fir (Abies concolor var. lowiana) (2). Found in protected areas where there are deep, moist soils, at altitudes between 1,100 and 1,500 metres above sea level (4).
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Habitat & Distribution

Cultivated. Shandong, Jiangsu, Jiangxi, Zhejiang (Hangzhou Shi) [native to W United States].
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Associations

In Great Britain and/or Ireland:
Plant / associate
fruitbody of Agaricus gennadii is associated with Sequoiadendron giganteum

Foodplant / pathogen
Armillaria mellea s.l. infects and damages Sequoiadendron giganteum

Plant / associate
fruitbody of Buchwaldoboletus lignicola is associated with rotting wood of Sequoiadendron giganteum
Other: major host/prey

Foodplant / saprobe
fruitbody of Hemimycena pseudolactea is saprobic on dead, fallen, decayed needle of litter of Sequoiadendron giganteum

Foodplant / saprobe
fruitbody of Lepiota ochraceofulva is saprobic on soil of tree of Sequoiadendron giganteum

Foodplant / pathogen
fruitbody of Phaeolus schweinitzii infects and damages live root of mature tree of Sequoiadendron giganteum
Other: minor host/prey

Foodplant / saprobe
fruitbody of Postia rennyi is saprobic on dead, decayed (very) wood of Sequoiadendron giganteum
Other: minor host/prey

Foodplant / saprobe
long-rooted fruitbody of Strobilurus stephanocystis is saprobic on buried, partially decayed cone of Sequoiadendron giganteum
Remarks: season: often in spring
Other: unusual host/prey

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Associated Forest Cover

Giant sequoia groves lie wholly within the Sierra Nevada Mixed Conifer  type-SAF (Society of American Foresters) forest cover type 243 (8). A  grove is distinguished from similar mesic habitats in this type only by  the presence of giant sequoia itself: no other species is restricted to  the groves (33). Nowhere does giant sequoia grow in a pure stand, although  in a few small areas it approaches this condition (16).

    Based on density or canopy coverage, groves typically are dominated  strongly by California white fir (Abies concolor var. lowiana),  despite the presence of emergent individuals of giant sequoia that  overtop the canopy. Sugar pine (Pinus lambertiana) is a  characteristic associate. Incense-cedar (Libocedrus decurrens) at  low elevations and California red fir (Abies magnifica) at high  elevations may rival California white fir for dominance. Ponderosa pine  (Pinus ponderosa) and California black oak (Quercus kelloggii)  often occupy drier sites within the grove boundaries. Trees less commonly  associated with giant sequoia include Jeffrey pine (Pinus jeffreyi),  Douglas-fir (Pseudotsuga menziesii), Pacific yew (Taxus  brevifolia), Pacific dogwood (Cornus nuttallii), California  hazel (Corylus cornuta var. californica), white alder (Alnus  rhombifolia), Scouler willow (Salix scoulerana), bigleaf maple  (Acer macrophyllum), bitter cherry (Prunus emarginata), and  canyon live oak (Quercus chrysolepis).

    Shrub species most often found in giant sequoia groves are bush  chinkapin (Castanopsis sempervirens), mountain misery (Chamaebatia  foliolosa), mountain whitethorn (Ceanothus cordulatus), littleleaf  ceanothus (C. parvifolius), deerbrush (C. integerrimus), snowbrush  (C. velutinus), greenleaf manzanita (Arctostaphylos patula),  western azalea (Rhododendron occidentale), Ribes spp.,  Rosa spp., and Rubus spp. (16,17,33,36).

    Stand structure and species frequency vary substantially with elevation,  latitude, exposure, soil moisture, and time since fire or other  disturbance. In general, protection of groves from fire has resulted in  increased prevalence of California white fir, reduced regeneration of  giant sequoia and pines, and reduced density of shrubs. The age-class  distribution of giant sequoia also varies widely among groves. Most groves  today, however, appear to lack sufficient young giant sequoias to maintain  the present density of mature trees in the future. In these groves, giant  sequoia regeneration evidently has been declining over a period of 100 to  500 years or more (33).

  • Burns, Russell M., and Barbara H. Honkala, technical coordinators. 1990. Silvics of North America: 1. Conifers; 2. Hardwoods.   Agriculture Handbook 654 (Supersedes Agriculture Handbook 271,Silvics of Forest Trees of the United States, 1965).   U.S. Department of Agriculture, Forest Service, Washington, DC. vol.2, 877 pp.   http://www.na.fs.fed.us/spfo/pubs/silvics_manual/table_of_contents.htm External link.
Creative Commons Attribution Non Commercial 3.0 (CC BY-NC 3.0)

C. Phillip Weatherspoon

Source: Silvics of North America

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Diseases and Parasites

Damaging Agents

Fire is the most universal and probably most  serious damaging agent of giant sequoia in its natural range (36).  Seedlings and saplings of giant sequoia, like those of most other tree  species, are highly susceptible to mortality or serious injury by fire.  However, in those locations most favorable for successful establishment  and early growth-that is, mineral soil seedbeds and well-lighted  openings-fuels tend to be sparser and to accumulate more slowly than in  adjacent forested areas. The more vigorous seedlings and saplings thus may  be large enough to survive a light fire by the time one occurs.

    Larger giant sequoias, because of their thick nonresinous bark and  elevated crowns, are more resistant to fire damage than associated  species. Nevertheless, repeated fires over the centuries sear through the  bark of a tree's base, kill the cambium, and produce an ever-enlarging  scar. Almost all of the larger trees have fire scars, many of which  encompass a large percentage of the basal circumference (16). Few veterans  have been killed by fire alone, but consequent reduction in supporting  wood predisposes a tree to falling. Furthermore, fire scars provide entry  for fungi responsible for root disease and heart rot (29). Decayed wood,  in turn, is more easily consumed by subsequent fires. The net result is  further structural weakening of the tree. In addition, fire scars have  been cited as the main cause of dead tops, so common in older trees (35).

    Lightning strikes, besides starting ground fires, sometimes knock out  large portions of crowns or ignite dead tops. Mature trees seldom are  killed by lightning, however (16).

    Old giant sequoias most commonly die by toppling. Weakening of the roots  and lower bole by fire and decay is primarily responsible (16,29). The  extreme weight of the trees, coupled with their shallow roots, increases  the effects of this weakening, especially in leaning trees. Other  causative factors include wind, water-softened soils, undercutting by  streams, and heavy snow loads (16).

    Although diseases are less troublesome for giant sequoia in its natural  range than for most other trees, the species is not as immune to disease  as once assumed (1). Heartwood of downed sequoia logs is extremely  durable, sometimes remaining largely intact for thousands of years. The  heartwood of living trees, however, is less resistant to decay (2). At  least nine fungi have been found associated with decayed giant sequoia  wood. Of these, Heterobasidion annosum, Armillaria mellea, Poria  incrassata, and P. albipellucida probably are most significant  (29). The first two species also are serious root pathogens. Diseases  generally do not kill trees past the seedling stage directly, but rather  by contributing to root or stem failure. No other types of diseases,  including seedling diseases, are known to be significant problems within  the natural range of giant sequoia (2). In nurseries and when planted  outside its natural range, however, giant sequoia is highly susceptible  to, and sometimes rapidly killed by, a number of organisms that may attack  it at any stage from seedlings to mature trees (1,25,39).

    Insect depredations do not seriously harm giant sequoias older than  about 2 years, although sometimes they may reduce vigor (17). Carpenter  ant (Camponotus spp.) galleries in decayed wood of tree  bases evidently are not a direct cause of tree failure. Carpenter ants and  other insects may facilitate the entry and spread of decay fungi, although  the importance of such a role is not well known (29). Like disease injury,  damage by insects is more significant outside the tree's natural range.

    Of various types of human impact on giant sequoia in the groves  (16,17,29), the most significant has been fire exclusion. The damage  caused by fire is outweighed by its benefits in perpetuating the species.  Fire is necessary to create and maintain conditions favorable for  regeneration (17). Furthermore, the elimination of frequent fires has  permitted a large buildup of both dead and live fuels, and an associated  increase in the potential for catastrophic crown fires. Agencies  responsible for managing most of the groves currently have programs  designed to reintroduce fire into giant sequoia ecosystems (15,27,31).

  • Burns, Russell M., and Barbara H. Honkala, technical coordinators. 1990. Silvics of North America: 1. Conifers; 2. Hardwoods.   Agriculture Handbook 654 (Supersedes Agriculture Handbook 271,Silvics of Forest Trees of the United States, 1965).   U.S. Department of Agriculture, Forest Service, Washington, DC. vol.2, 877 pp.   http://www.na.fs.fed.us/spfo/pubs/silvics_manual/table_of_contents.htm External link.
Creative Commons Attribution Non Commercial 3.0 (CC BY-NC 3.0)

C. Phillip Weatherspoon

Source: Silvics of North America

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General Ecology

Fire Management Implications

More info for the term: natural

This study investigated methods by which the impacts of prescribed fire
on certain biotic and abiotic elements of the sequoia-mixed conifer
forest ecosystem could be measured.  Giant sequoia was present as a
co-dominant species with an estimated 11.4 trees per acre (28.2/ha).  A
comparison of results was detailed from previous high-severity 1969 burn
to the lower-severity 1970 burn reported here.  In summary, a high-severity
burn followed by another moderate-severity burn 7 to 10 years later is
an option for obtaining management objectives on a mixed sequoia stand;
or, alternatively, implement two low-severity burns in closer sequence
in order to gradually kill young seedlings and cleanup heavy fuels.
Both strategies would allow for more natural regeneration of seral species,
while reducing the potential threat of hazardous wildfires.

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Site Description

More info for the term: fuel

The elevation along the ridge ranges from 6,400 feet (1,950 m) at the
saddle to nearly 7,000 feet (2,134 m).  Hygrothermograph records show a
yearly low of 17 degrees Fahrenheit (-8.4 deg C) and a high of 82
degrees Fahrenheit (28 deg C).  Temperatures in November just before the
burn ranged from 32 to 58 degrees Fahrenheit (0-15 deg C).  Relative
humidity fluctuated between 30 and 80 percent.  Winds in and near the
study plots were moderate when present, varying from 0 to 5 mph (0.3
kmh).  Average slope was 35 percent.  Large portions of this study area
were found on soils derived from metamorphic schists.

Burn day conditions were as follows:

        Temperature: 59 deg F (15 deg C)
        Humidity: 20 percent
        10-hour fuel sticks: 10 grams
        Wind speed: 0 mph

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Fire Management Considerations

More info for the terms: fire management, fire regime, fire suppression, high-severity fire, natural, prescribed burn

Research on the importance of periodic fire in maintaining natural giant
sequoia forests has justified the need to restore a natural fire regime.
The principal goal of fire management in giant sequoia groves in
Sequoia, Kings Canyon, and Yosemite National Parks is to restore or
maintain the natural fire regime to the maximum extent possible.
Prescribed burns are now conducted by igniting fires in a spot pattern
and allowing nature to produce a mosaic of effects [20].

The long-standing fire suppression policy of federal and state land
agencies has created at least two major problems for the giant sequoia:
(1) the continuing reproduction of the species has been seriously
hampered and (2) the build-up of dead fuels and the growth of other
young trees in the understory pose threats of destructive forest fires
in the crowns of existing groves.  In 1969, the National Park Service
began a program or prescribed burning in Kings Canyon National Park.
Prescribed burning has produced relatively few deleterious side effects
on giant sequoia groves [27].

Prescribed burning is currently an active management strategy in giant
sequoia groves.  Fire prepares seedbeds, recycles nutrients, maintains
successional diversity, decreases the number of trees susceptible to
attack by insects and disease, reduces fire hazards, and favors wildlife
[5,10,27].  A prescribed burn in Kings Canyon National Park resulted in
an increase in flycatcher and robin numbers [4,13].  A number of changes
in bird and mammal populations are forecasted if fire is reintroduced on
a large scale.  High-severity fire will increase the number of
trunk-feeding birds preying on the increased amount of insects [12].

Prior to protection under Park status in 1864, the Mariposa Grove and
Yosemite National Park sustained fires every 20 to 25 years [9].  Other
research found that in presettlement times, any given site in the middle
elevations of the Sierra was burned over every 5 to 10 years [18,27].
  • 10.  Hartesveldt, Richard J.; Harvey, H. Thomas; Shellhammer, Howard S.;        Stecker, Ronald E. 1975. The sequoia of the Sierra Nevada. Washington,        DC: U.S. Department of the Interior, National Park Service. 180 p.        [4233]
  • 12.  Harvey, H. Thomas; Shellhammer, Howard S.; Stecker, Ronald E. 1980.        Giant sequoia ecology: Fire and reproduction. Scientific Monograph        Series No 12. Washington, DC: U.S. Department of the Interior, National        Park Service. 182 p.  [6587]
  • 13.  Kilgore, Bruce M. 1971. Response of breeding bird populations to habitat        changes in a giant sequoia forest. American Midland Naturalist. 85(1):        135-152.  [7281]
  • 18.  Martin, Robert E. 1982. Fire history and its role in succession. In:        Means, Joseph E., ed. Forest succession and stand development research        in the Northwest: Proceedings of a symposium; 1981 March 26; Corvallis,        OR. Corvallis, OR: Oregon State University, Forest Research Laboratory:        92-99.  [9830]
  • 20.  Parsons, David J.; Nichols, H. Thomas. 1986. Management of giant sequoia        in the national parks of the Sierra Nevada, California. In:        Weatherspoon, C. Phillip; Iwamoto, Y. Robert; Piirto, Douglas D.,        technical coordinators. Proceedings of the workshop on management of        giant sequoia; 1985 May 24-25; Reedley, CA. Gen. Tech. Rep. PSW-95.        Berkeley, CA: U.S. Department of Agriculture, Forest Service, Pacific        Southwest Forest and Range Experiment Station: 26-29.  [9807]
  • 27.  Vale, Thomas R. 1975. Ecology and environmental issues of the Sierra        Redwood (Sequoiadendron giganteum), now restricted to California.        Environmental Conservation. 2(3): 179-188.  [8776]
  • 4.  Bock, Carl E.; Lynch, James F. 1970. Breeding bird populations of burned        and unburned conifer forest in the Sierra Nevada. Condor. 72: 182-189.        [5113]
  • 5.  Boe, Kenneth N. 1974. Sequoiadendron giganteum (Lindl.) Buchholz Giant        sequoia. In: Schopmeyer, C. S., ed. Seeds of woody plants in the United        States. Agriculture Handbook No. 450. Washington: U. S. Department of        Agriculture, Forest Service: 767-768.  [7751]
  • 9.  Hartesveldt, R. J.; Harvey, H. T. 1968. The fire ecology of Sequoia        regeneration. In: Proceedings, Tall Timbers fire ecology conference;        1967 November 9-10; Hoberg. No. 7. Tallahassee, FL: Tall Timbers        Research Station: 65-77.  [6384]

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Broad-scale Impacts of Plant Response to Fire

More info for the terms: basal area, duff, fuel, fuel moisture, litter, prescribed fire, tree

A fall prescribed fire in the Tharp Creek Watershed of Sequoia National Park
resulted in no giant sequoia mortality on a white fir-mixed conifer
site monitored for 5 years after fire. The fire burned from 23 to 26 October
1990. Relative humidity during the day was 21% to 30% and at night was 30%
to 40%. Fuel moisture levels in the litter and duff averaged 28%. For 100-hour
and 1,000-hour fuels, moisture levels were 14% and 64%, respectively. At the
time of ignition, air temperatures were 50 to 61 °F (10-16 °C), and winds were
calm. The fire was a combination of backing and strip head fires with flame lengths
of 0.16 to 7.9 feet (0.05-2.4 m). One-hour, 10-hour, and 100-hour fuels
were reduced by 96%, 77%, and 60%, respectively.  Tree (≥4.6 feet (1.4 m))
mortality was evaluated before and after fire as well as from an unburned
reference site. Basal area changes were also monitored before and after
the fire. Compared to the unburned control, mean annual percent change in giant
sequoia basal area increased by an average of 1.27% on the burned site before
the fire. From 1989 to 1994 (includes 1 year of prefire data), giant sequoia basal
area increased by 0.90% on the burned site compared to the control [31]. For
more information, see the entire Research Paper by Mutch and Parsons [31].
  • 31.  Mutch, Linda S.; Parsons, David J. 1998. Mixed conifer forest        mortality and establishment before and after prescribed fire in Sequoia        National Park, California. Forest Science. 44(3): 341-355.  [29033]

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Plant Response to Fire

High-severity fires will generally kill pole-size and younger trees.
Immediately following the passage of fire, seeds will drop as a reaction
to hot convectional air movement through the canopy.  Seeds will
germinate on the favorable mineral seedbeds created by the fire [5].

Postfire seedling establishment:  When high-severity fires burn in dense
stands of mature giant sequoias, as many as 40,485 seedlings per acre
(100,000/ha) may develop following heat-induced seedfall [11].  After a
prescribed burn in Sequoia and Kings Canyon National Parks, a
high-severity burn resulted in 40,000 seedlings per acre (98,800/ha) the
first year after burning.  A lower-severity burn resulted in 13,000
seedlings per acre (32,110/ha).  Not a single giant sequoia seedling was
found on the unburned control plot in this study [5].
  • 11.  Harvey, H. Thomas; Shellhammer, Howard S. 1991. Survivorship and growth        of giant sequoia (Sequoiadendron giganteum (lindl.)buchh.) seedlings        after fire. Madrona. 38(1): 14-20.  [14879]
  • 5.  Boe, Kenneth N. 1974. Sequoiadendron giganteum (Lindl.) Buchholz Giant        sequoia. In: Schopmeyer, C. S., ed. Seeds of woody plants in the United        States. Agriculture Handbook No. 450. Washington: U. S. Department of        Agriculture, Forest Service: 767-768.  [7751]

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Immediate Effect of Fire

More info for the terms: cover, tree

In Sequoia and Kings Canyon National Parks, a moderate-severity
prescribed fire contributed little to the mortality of giant sequoia
that were larger than 1 foot (0.30 m) d.b.h.  Additionally, there is no
evidence that previous fire scarring had any relationship to tree
mortality [5].  Low- to moderate-severity fires scorch the bark of giant
sequoia and usually cause scarring.  High-severity fires may reach the
crown and consume part or all of the canopy cover [2].  A direct
relationship exists between the size of the basal fire scar in mature
giant sequoias and the the likelihood of damage to the top or foliage of
the trees [23].  Reduction of supporting wood from scarring predisposes
the tree to falling, and provides an opening for fungi responsible for
root disease and heart rot [28].
  • 2.  Biswell, H. H. 1961. The big trees and fire. National Parks Magazine.        April: 1-4.  [8786]
  • 23.  Rundel, Philip W. 1973. The relationship between basal fire scars and        crown damage in giant sequoia. Ecology. 54(1): 210-213.  [6639]
  • 28.  Weatherspoon, C. Philip. 1990. Sequoiadendron giganteum (Lindl.)        Buchholz. In: Burns, Russell M.; Honkala, Barbara H., technical        coordinators. Silvics of North America. Volume 1. Conifers. Agric.        Handb. 654. Washington, DC: U.S. Department of Agriculture, Forest        Service: 552-562.  [13415]
  • 5.  Boe, Kenneth N. 1974. Sequoiadendron giganteum (Lindl.) Buchholz Giant        sequoia. In: Schopmeyer, C. S., ed. Seeds of woody plants in the United        States. Agriculture Handbook No. 450. Washington: U. S. Department of        Agriculture, Forest Service: 767-768.  [7751]

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Fire Ecology

More info for the terms: climax, litter, serotinous

Fire is the most serious damaging agent to young giant sequoia.
Seedlings and saplings are highly susceptible to mortality or serious
injury by fire.  Giant sequoia exhibits the following adaptations to
fire:  rapid growth, fire resistant bark, elevated canopies and
self-pruned lower branches, latent buds, and serotinous cones [10,12].
Mature giant sequoia are more resistant to fire damage and few are
killed by fire alone [28].

Giant sequoia groves represent a fire climax community whose stability
is maintained by frequent fires.  In the absence of regular ground
fires, litter accumulates on the forest floor and limits germination and
establishment of seedlings [24].  Giant sequoia in Whitaker's Forest,
California, produced 9,089 pounds per acre (10,181 kg per ha) of ground
litter [3].  If these conditions are maintained in the future, the
groves will become a long-standing seral community trending toward a
mature white fir forest without giant sequoia [24].
  • 10.  Hartesveldt, Richard J.; Harvey, H. Thomas; Shellhammer, Howard S.;        Stecker, Ronald E. 1975. The sequoia of the Sierra Nevada. Washington,        DC: U.S. Department of the Interior, National Park Service. 180 p.        [4233]
  • 12.  Harvey, H. Thomas; Shellhammer, Howard S.; Stecker, Ronald E. 1980.        Giant sequoia ecology: Fire and reproduction. Scientific Monograph        Series No 12. Washington, DC: U.S. Department of the Interior, National        Park Service. 182 p.  [6587]
  • 24.  Rundel, Philip W.; Parsons, David J.; Gordon, Donald T. 1977. Montane        and subalpine vegetation of the Sierra Nevada and Cascade Ranges. In:        Barbour, Michael G.; Major, Jack, eds. Terrestrial vegetation of        California. New York: John Wiley & Sons: 559-599.  [4235]
  • 28.  Weatherspoon, C. Philip. 1990. Sequoiadendron giganteum (Lindl.)        Buchholz. In: Burns, Russell M.; Honkala, Barbara H., technical        coordinators. Silvics of North America. Volume 1. Conifers. Agric.        Handb. 654. Washington, DC: U.S. Department of Agriculture, Forest        Service: 552-562.  [13415]
  • 3.  Biswell, H. H.; Gibbens, R. P.; Buchanan, H. 1966. Litter production by        bigtrees and associated species. California Agriculture. 20(9): 5-7.        [12692]

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Successional Status

More info on this topic.

More info for the term: density

Giant sequoia has adapted to keep its crown higher than that of its
associates.  On disturbed sites, giant sequoia is a strong competitor,
although never totally dominating a stand [10].  Current data does not
indicate that any enlargement of giant sequoia groves is taking place.
Mature giant sequoia mark the outer boundaries, which have remained
stable over a period of 500 to 1,000+ years.  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 sequoias are currently undergoing a gradual decline in
density since the European settlement days [24].
  • 10.  Hartesveldt, Richard J.; Harvey, H. Thomas; Shellhammer, Howard S.;        Stecker, Ronald E. 1975. The sequoia of the Sierra Nevada. Washington,        DC: U.S. Department of the Interior, National Park Service. 180 p.        [4233]
  • 24.  Rundel, Philip W.; Parsons, David J.; Gordon, Donald T. 1977. Montane        and subalpine vegetation of the Sierra Nevada and Cascade Ranges. In:        Barbour, Michael G.; Major, Jack, eds. Terrestrial vegetation of        California. New York: John Wiley & Sons: 559-599.  [4235]

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Regeneration Processes

More info for the terms: monoecious, tree

Giant sequoia regenerates primarily by seed, although occasionally it
may reproduce naturally by vegetative methods.  Giant sequoias up to
about 20 years of age may produce stump sprouts subsequent to injury.
Giant sequoia of all ages may sprout from the bole when old branches are
lost to fire or breakage.  Cuttings from juvenile donors root quickly
and in high percentages (up to 94 percent) [10].

Flowering and fruiting:  Giant sequoia is monoecious; male and female
cone buds form during late summer.  Pollination takes place between the
middle of April and May.  Fertilization usually occurs in August when
the cones are nearly full-sized.  Embryos develop rapidly during the
next summer and reach maturity at the end of the second growing season.

Seed production and dissemination:  Young trees start to bear cones at
the age of 20 years.  Cones may remain attached to the tree for 8 to 12
years and much of the seed will be retained.  During the late summer,
however, some seed is shed when the cone scales shrink.  Most seeds are
liberated when the cone dries out and becomes detached.  Each cone yields
an average of 230 seeds.  The average number of cleaned seeds per pound
is approximately 81,000 (200,070/kg).  Stored giant sequoia seed remains
moderately viable for many years [5,10,28].  At any given time, a large
tree may be expected to have approximately 11,000 cones.  The upper part
of the crown of any mature giant sequoia invariably produces a greater
abundance of cones than its lower portions.

A mature giant sequoia has been estimated to disperse from 300,000 to
400,000 seeds per year.  Seed dispersal results from seed falling from
the tree-top, insect and rodent activity, or by cones falling to the
ground.  The winged seeds may be carried up to 600 feet (183 m) from the
parent tree.

Seedling development:  Giant sequoia seeds germinate best when totally
buried in disturbed mineral soil.  April, May, September, and October
temperatures are best for early development.  Soil moisture conditions
and seedling survival are generally better in spring than during any
other season.  Light conditions are generally best for growing at
one-half full sunlight.  Upon germination, the seedling stands 3/4 to 1
inch (1.9-2.5 cm) high, usually with four cotyledons.  By autumn,
seedlings have up to six branches and are 3 to 4 inches (8-10 cm) tall.
After the second year, the seedling attains a height of 8 to 12 inches
(20-30 cm) with a taproot penetrating to a depth of 10 to 15 inches
(25-38 cm) [28].

Growth and yield:  Giant sequoia is the worlds largest tree in terms of
total volume.  Beyond the seedling stage, giant sequoia unhindered by an
overstory continues to grow at the same rate as its competitors.  Yields
of second growth stands dominated by giant sequoia were found to equal
or slightly exceed those of second-growth mixed-conifer stands on the
same site.  Lower branches die fairly readily from shading, but trees
less than 100 years old retain most of their dead branches.  Boles of
mature trees generally are free of branches to a height of 98 to 148
feet (30-40 m) [28].
  • 10.  Hartesveldt, Richard J.; Harvey, H. Thomas; Shellhammer, Howard S.;        Stecker, Ronald E. 1975. The sequoia of the Sierra Nevada. Washington,        DC: U.S. Department of the Interior, National Park Service. 180 p.        [4233]
  • 28.  Weatherspoon, C. Philip. 1990. Sequoiadendron giganteum (Lindl.)        Buchholz. In: Burns, Russell M.; Honkala, Barbara H., technical        coordinators. Silvics of North America. Volume 1. Conifers. Agric.        Handb. 654. Washington, DC: U.S. Department of Agriculture, Forest        Service: 552-562.  [13415]
  • 5.  Boe, Kenneth N. 1974. Sequoiadendron giganteum (Lindl.) Buchholz Giant        sequoia. In: Schopmeyer, C. S., ed. Seeds of woody plants in the United        States. Agriculture Handbook No. 450. Washington: U. S. Department of        Agriculture, Forest Service: 767-768.  [7751]

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Growth Form (according to Raunkiær Life-form classification)

More info on this topic.

More info for the term: phanerophyte

  
   Phanerophyte

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Life Form

More info for the term: tree

Tree

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Season/Severity Classification

Fall burn/low- to moderate-severity

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Broad-scale Impacts of Fire

Despite the general belief that giant sequoia wood is not especially
flammable, it burns hotly when splintered and dry [10].
  • 10.  Hartesveldt, Richard J.; Harvey, H. Thomas; Shellhammer, Howard S.;        Stecker, Ronald E. 1975. The sequoia of the Sierra Nevada. Washington,        DC: U.S. Department of the Interior, National Park Service. 180 p.        [4233]

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Post-fire Regeneration

   crown-stored residual colonizer; long-viability seed in on-site cones
   off-site colonizer; seed carried by wind; postfire years 1 and 2
   off-site colonizer; seed carried by animals or water; postfire yr 1&2

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Reaction to Competition

Giant sequoia is shade intolerant  throughout its life. Of its common coniferous associates, ponderosa pine  is also intolerant, sugar pine is intermediate in tolerance, incense-cedar  is intermediate to tolerant, and California white fir is tolerant (17).

    Fires or other disturbances that bare mineral soil and open the canopy  characteristically benefit intolerant species, including giant sequoia,  and move plant communities to earlier successional stages. In contrast,  successful regeneration of giant sequoia in shade and in the absence of  disturbance is less likely than that of any associated conifer (17).

    Once established, and with adequate light, young giant sequoias maintain  dominance over competitors through rapid growth. In dense thickets,  however, trees stagnate and recover slowly if released (36). At maturity,  giant sequoias are the tallest trees in the forest.

    Although conspicuous in late successional communities dominated by  California white fir, giant sequoia is not a true climax-stage species,  because it fails to reproduce itself successfully in an undisturbed  forest. Instead, mature trees are successional relicts because they live  for many centuries while continuing to meet their light requirements by  virtue of their emergent crowns (16).

    If various natural agents of disturbance-especially fire-operated  freely, giant sequoia groves would consist of a roughly steady-state  mosaic of even-aged groups of trees and shrubs in various stages of  succession. The patchy nature of vegetational units would correspond to  the pattern of disturbances. In the absence of disturbance, however,  successional pathways converge toward a multilayered climax forest of pure  California white fir (4). In fact, since the advent of fire suppression,  density of California white fir has increased markedly, while densities of  early successional stage species have decreased (26).

  • Burns, Russell M., and Barbara H. Honkala, technical coordinators. 1990. Silvics of North America: 1. Conifers; 2. Hardwoods.   Agriculture Handbook 654 (Supersedes Agriculture Handbook 271,Silvics of Forest Trees of the United States, 1965).   U.S. Department of Agriculture, Forest Service, Washington, DC. vol.2, 877 pp.   http://www.na.fs.fed.us/spfo/pubs/silvics_manual/table_of_contents.htm External link.
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C. Phillip Weatherspoon

Source: Silvics of North America

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Rooting Habit

During the first few years, the root system of  giant sequoia seedlings consists of a taproot with few laterals-a habit  that facilitates survival during dry summers (36). The ratio of root  length to shoot height during this period is about 2 to 2.5, with drier  sites having higher ratios (17). After 6 to 8 years, lateral root growth  predominates, and elongation of the taproot practically stops (36).

    Roots of a mature tree commonly extend 30 m (100 ft) or more from the  bole in well-drained soils, and occupy an area of 0.3 ha (0.7 acre) or  more. Along drainage bottoms or edges of meadows, the radial extent of the  root system may be no more than 12 to 15 m (40 to 50 ft). The largest  lateral roots are usually no more than 0.3 m (1 ft) in diameter. Few roots  extend deeper than 1 m (3 ft), and even less in areas with a high water  table. Most of the abundant feeder roots are within the upper 0.6 m (2 ft)  of soil. Concentrations of feeder roots often are high at the mineral soil  surface (16).

    Immature trees, both in the groves and in older plantings, are notably  windfirm (20). Considering the shallowness of the root system and the  great aboveground mass of large giant sequoias, it is remarkable that so  many of these giants, especially leaners, remain standing for so long  (16).

    Root grafting is common in giant sequoia (16,36).

  • Burns, Russell M., and Barbara H. Honkala, technical coordinators. 1990. Silvics of North America: 1. Conifers; 2. Hardwoods.   Agriculture Handbook 654 (Supersedes Agriculture Handbook 271,Silvics of Forest Trees of the United States, 1965).   U.S. Department of Agriculture, Forest Service, Washington, DC. vol.2, 877 pp.   http://www.na.fs.fed.us/spfo/pubs/silvics_manual/table_of_contents.htm External link.
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Life History and Behavior

Cyclicity

Phenology

More info on this topic.

Giant sequoia flowers from April to May; cone ripening and seed
dispersal occurs in the spring and summer months.  Seeds dropped just
before the first snow or just as the snow melts may have the best chance
of germinating and becoming successfully established.  Growth of giant
sequoia generally begins in the early spring to late fall [28].
  • 28.  Weatherspoon, C. Philip. 1990. Sequoiadendron giganteum (Lindl.)        Buchholz. In: Burns, Russell M.; Honkala, Barbara H., technical        coordinators. Silvics of North America. Volume 1. Conifers. Agric.        Handb. 654. Washington, DC: U.S. Department of Agriculture, Forest        Service: 552-562.  [13415]

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Reproduction

Vegetative Reproduction

Giant sequoias up to about 20 years of  age may produce stump sprouts subsequent to injury (19). Unlike redwood  (Sequoia sempervirens), older trees normally do not sprout from  stumps or roots. A recent report (30), however, noted sprouts on two small  stumps from suppressed trees about 85 years old. Giant sequoias of all  ages may sprout from the bole when old branches are lost by fire or  breakage (17,36).

    Cuttings from juvenile donors root quickly and in high percentages (up  to 94 percent) (3,10,12). Limited success has been achieved in rooting  cuttings from older (30- or 40-year-old) trees (3,10). Differences in  vegetative regeneration capacities between juvenile and older donors may  be reduced if cuttings are taken at the time of budbreak, instead of  during the dormant period (24).

  • Burns, Russell M., and Barbara H. Honkala, technical coordinators. 1990. Silvics of North America: 1. Conifers; 2. Hardwoods.   Agriculture Handbook 654 (Supersedes Agriculture Handbook 271,Silvics of Forest Trees of the United States, 1965).   U.S. Department of Agriculture, Forest Service, Washington, DC. vol.2, 877 pp.   http://www.na.fs.fed.us/spfo/pubs/silvics_manual/table_of_contents.htm External link.
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C. Phillip Weatherspoon

Source: Silvics of North America

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Seedling Development

Natural reproduction in giant sequoia is  an unusually tenuous process. Of the enormous numbers of seeds shed each  year, extremely few encounter the combination of conditions necessary to  become successfully established seedlings.

    In contrast with most coniferous seeds, a large majority of seeds of  giant sequoia die from desiccation and solar radiation soon after reaching  the forest floor, especially during the summer. In one study, viability of  seeds removed from fresh cones and placed on the ground dropped from 45  percent to 0 in 20 days. Seeds collected from the forest floor showed an  average viability of 1 percent (17).

    Seed dormancy is not evident in giant sequoia, so surviving seeds  germinate as soon as conditions are favorable (17). Germination is  epigeal. The most significant requirement for germination is an adequate  supply of moisture and protection of the seed from desiccation. This is  best provided by moist, friable mineral soil that covers the seed to a  depth of 1 cm (0.4 in), and that is partially shaded to reduce surface  drying. A wide range of temperatures is acceptable for germination. The  generally sandy soils of the groves normally provide the additional  requirement of adequate aeration and the optimum pH range of 6 to 7 (38).  Because of rapid percolation, however, adequate moisture retention for  germination and initial root development is often marginal.

    Seeds dropped just before the first snow or just as the snow melts may  have the best chance of germinating and becoming successfully established.  Seedlings that produce roots early in the season during favorable soil  moisture conditions are more likely to survive the dry summer. The first  stage of germination-extension of the radicle-sometimes takes place  beneath the snow (16).

    Thick litter usually dries too quickly for seeds to germinate, and  virtually all seedlings that do get started die before their roots can  penetrate to mineral soil (17,36). Only in exceptionally wet years do  significant numbers of seedlings become established on undisturbed forest  floor. The role of damping-off fungi in the mortality of natural giant  sequoia seedlings is not well known, but they are almost certainly a   greater problem on thick litter than on mineral soil (2,25). After  seedlings are established on more favorable seedbeds, a light covering of  litter can moderate soil surface temperatures and retard drying (37).

    Seedlings rarely become established in dense grass cover, probably  because moisture is depleted in the surface soil early in the season (36).

    Soil disturbance and increased availability of light and moisture  resulting from past logging in some of the groves have led to  establishment of several fine young-growth stands dominated by giant  sequoia. Mechanical seedbed preparation is currently a legitimate  regeneration option in some groves, although such treatment is  inconsistent with management direction in most of the natural range of the  species.

    Of the various types of natural disturbances that may remove litter and  bare mineral soil, fire is undoubtedly the most significant. Locally  intense or highly consumptive fires are more effective than light surface  fires or physical disturbance in promoting germination and subsequent  seedling survival and early growth (17). The resulting short-lived friable  soil condition facilitates seed penetration beneath the surface and root  penetration following germination. Increased wettability in the surface  soil layers resulting from high temperatures appears to improve water  penetration and retention in the zones important for seeds and young  seedlings. Fire also may kill some understory trees, thereby providing  more light to speed the development (especially root penetration) of the  shade-intolerant giant sequoia seedlings. Additional benefits include  providing a surge of available nutrients, reducing populations of fungi  potentially pathogenic to seedlings, and killing seeds and rootstocks of  competing vegetation (17).

    On the other hand, the dark surface and possibly increased insolation  resulting from fire may cause more desiccation and heat killing of giant  sequoia seeds and seedlings at the surface. Also, populations of  endomycorrhizal fungi may be severely reduced temporarily (17). And  low-consumption fires, rather than reducing competing vegetation, may  instead greatly stimulate germination and sprouting of shrubs. Partially  burned litter, in terms of its suitability for successful seedling  establishment, ranks between undisturbed forest floor and areas subjected  to hot fires (38).

    First-year giant sequoia seedlings established on treated-bulldozed or  burned or both-areas were 30 to 150 times more numerous than those on  undisturbed forest floor (17). Mortality of first-year seedlings during  the 3 summer months on one treated area averaged 39 percent, with an  additional 25 percent dying during the next 9 months. Desiccation was the  primary cause of mortality in the summer. During a year of increased  seasonal precipitation, mortality attributable to desiccation decreased,  whereas that caused by insects increased to 25 percent of total mortality.  Heat canker, damage by birds and mammals, and fungal attacks were of minor  importance.

    In the same study, direct mortality of first-year seedlings from insect  predation ranged from 3 to 18 percent of all seedlings present. Some of  the significant additional insect damage probably caused delayed  mortality. Largest seedling losses were in areas recently disturbed,  especially by fire, probably because alternative food sources were reduced  temporarily. Insects responsible for the damage were early instars of Pristocauthophilus  pacificus, a camel cricket, and larvae of the geometrids Sabulodes  caberata and Pero behrensaria.

    Survival of sequoia seedlings for a 7- to 9-year period was 27 percent  on areas subjected to a hot burn as opposed to 3.5 percent on other  treated substrates. No seedlings survived in undisturbed areas. In another  instance, only 1.4 percent of seedlings established following light  surface burning were alive after two summers. Mortality slows  substantially after the first 2 or 3 years. At the end of 3 years,  surviving seedlings usually have root systems that penetrate the soil to  depths that supply adequate moisture through the summer, or to about 36 cm  (14 in).

    Height growth of giant sequoia seedlings in the groves is relatively  slow during the first few years, presumably because of competition for  light and moisture from the larger trees. Seedlings 7 to 10 years old had  grown at an average rate of about 4 cm (1.6 in) per year. Periodic annual  height increment from 10 to 20 years was only 5 em (2 in). Seedlings grew  significantly faster on areas subjected to hot burns than they did  elsewhere (17).

    In contrast, giant sequoia seedlings in the open grow rapidly and, given  an even start, can outgrow any associated tree species. Height growth up  to 60 cm (24 in) per year is not uncommon (9).

    Up to 2 or 3 years of age, seedlings growing in dense shade (less than  25 percent of full sunlight) survive about as well as others, but grow  poorly and develop abnormally (37). At higher light levels, one study  found moderate reduction in height growth compared with seedlings in full  sunlight (37), whereas another study found no significant effect of  reduced light on height growth (17). The adverse effects of shade on older  giant sequoias are more conspicuous with respect to both mortality and  growth reduction.

  • Burns, Russell M., and Barbara H. Honkala, technical coordinators. 1990. Silvics of North America: 1. Conifers; 2. Hardwoods.   Agriculture Handbook 654 (Supersedes Agriculture Handbook 271,Silvics of Forest Trees of the United States, 1965).   U.S. Department of Agriculture, Forest Service, Washington, DC. vol.2, 877 pp.   http://www.na.fs.fed.us/spfo/pubs/silvics_manual/table_of_contents.htm External link.
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Seed Production and Dissemination

Cones bearing fertile seeds  have been observed on trees as young as 10 years of age, but the large  cone crops associated with reproductive maturity usually do not appear  before about 150 or 200 years. Unlike most other organisms, giant sequoia  seems to continue its reproductive ability unabated into old age. The  largest specimens (not necessarily the oldest) bear heavy crops of cones  containing viable seeds (16,36).

    Giant sequoias have serotinous cones which, at maturity, may remain  attached to the stems without opening to release seeds. For 20 years or  more, cones may retain viable seeds and continue to photosynthesize and  grow, their peduncles producing annual rings that can be used to determine  cone age (16,36).

    A typical mature giant sequoia produces an average of 1,500 new cones  each year, although variability among trees and from year to year is  great. Cones produced during years with ample soil moisture are more  numerous (more than 20,000 cones on one large tree in an exceptional year)  and yield seeds of greater viability than those produced in dry years. The  upper third of the crown generally bears at least two-thirds of the cone  crop. Because of extended cone retention, a mature tree may have 10,000 to  30,000 cones at any given time, two-thirds of which may be green and  closed, and the remainder opened, brown, and largely seedless (16,17).

    Estimates of percent germination of seeds removed from green cones range  from about 20 to 40 percent (11,17,38). A number of variables, however,  account for departures from these average values. Trees growing on rocky  sites yield seeds with substantially higher germinability than those on  bottom lands with deeper soils. Larger seeds germinate in higher  percentages than small ones. In tests of cone age, germination increased  from 20 percent for seeds from 2-year-old cones to 52 percent for  5-year-old cones, then dropped to 27 percent for cones 8 years of age.  Germinability also varies with cone location in the crown, seed position  within the cones, and among groves (16). Artificial stratification of  seeds for 60 days or more resulted in faster germination, but not in  higher germination percent (11).

    Browning or drying of cones, with subsequent shrinkage of scales and  dispersal of seeds, is brought about largely by three agents, two of which  are animals. The more effective of the two is Phymatodes nitidus, a  long-horned wood-boring beetle. The larvae of the beetle mine the fleshy  cone scales and cone shafts, damaging occasional seeds only incidentally.  As vascular connections are severed, scales successively dry and shrink,  allowing the seeds to fall. Cones damaged during the summer open several  scales at a time, beginning during late summer and fall, and continuing  for 6 months to 1 year (17).

    The second animal having a significant role in giant sequoia  regeneration is the chickaree, or Douglas squirrel (Tamiasciurus  douglasi). The fleshy green scales of younger sequoia cones are a  major food source for the squirrel. The seeds, too small to have much food  value, are dislodged as the scales are eaten. During years of high  squirrel densities, the animals tend to cut large numbers of cones and  store and eat them at caches. When squirrels are few, most of the cone  consumption is in tree crowns-a habit more conducive to effective seed  dispersal. The squirrels are active all year (17).

    The chickaree prefers cones 2 to 5 years old, whereas Phymatodes is  more prevalent in cones at least 4 years old. The combined activities  of these animals help to ensure that seeds of all age classes are shed,  and that rate of seedfall is roughly constant throughout the year and from  year to year, despite variability in new cone production. An average rate  is about 1 million seeds per hectare (400,000/acre) per year (17).

    The third and perhaps most important agent of seed release is fire. Hot  air produced by locally intense fire and convected high into the canopy  can dry cones, resulting in release of enormous quantities of seed over  small areas-for example, 20 million/ha (8 million/acre) (17). This  increased seedfall coincides both spatially and temporally with  fire-related seedbed conditions favorable for seed germination and  seedling survival (fig. 2).

    Giant sequoia seeds are well adapted for wind dispersal. They are light  (average 200,000/kg [91,000/lb]), winged, and fall in still air at a rate  of 1.2 to 1.8 m (4 to 6 ft) per second. Winds common in late summer and  winter storms in the Sierra Nevada can disperse seeds more than 0.4 km  (0.25 mi) from the tall crowns of mature trees (16,36).

    Cone and seed insects other than Phymatodes have only a minor  impact on seed production (17).

    Birds and mammals exert a negligible effect on giant sequoia seeds on  the ground. Sequoia seeds consistently rank at or near the bottom in food  preference tests that include seeds of associated species, primarily  because they are small and contain little energy (17,38).

  • Burns, Russell M., and Barbara H. Honkala, technical coordinators. 1990. Silvics of North America: 1. Conifers; 2. Hardwoods.   Agriculture Handbook 654 (Supersedes Agriculture Handbook 271,Silvics of Forest Trees of the United States, 1965).   U.S. Department of Agriculture, Forest Service, Washington, DC. vol.2, 877 pp.   http://www.na.fs.fed.us/spfo/pubs/silvics_manual/table_of_contents.htm External link.
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Flowering and Fruiting

Giant sequoia is monoecious; male and  female cone buds form during late summer. Pollination takes place between  the middle of April and the middle of May when the female conelets are  only two or three times as large in diameter as the twigs bearing them.  Fertilization usually occurs in August, by which time cones are almost  full-size. Embryos develop rapidly during the next summer and reach  maturity at the end of the second growing season. The egg-shaped mature  cones, 5 to 9 cm (2.0 to 3.5 in) in length, yield an average of 200 seeds  each (16,17,36).

  • Burns, Russell M., and Barbara H. Honkala, technical coordinators. 1990. Silvics of North America: 1. Conifers; 2. Hardwoods.   Agriculture Handbook 654 (Supersedes Agriculture Handbook 271,Silvics of Forest Trees of the United States, 1965).   U.S. Department of Agriculture, Forest Service, Washington, DC. vol.2, 877 pp.   http://www.na.fs.fed.us/spfo/pubs/silvics_manual/table_of_contents.htm External link.
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Growth

Growth and Yield

One tree species has a greater diameter than  giant sequoia, three grow taller, and one lives longer (16). In terms of  volume, however, the giant sequoia is undisputedly the world's largest  tree. The most massive specimen, the General Sherman tree, located in  Sequoia National Park, has an estimated bole volume of 1486 m³  (52,500 ft³) (13). The greatest known height for the species is 94.5  m (310 ft), and the greatest mean d.b.h.- for the General Grant tree, in  Kings Canyon National Park- is 881 cm (347 in). The indicated mean d.b.h.  includes a large abnormal buttress; excluding this abnormality gives a  more realistic estimate of the maximum mean d.b.h. for the  species-approximately 823 cm (324 in) (13). Mature specimens commonly  reach a diameter of 305 to 610 cm (120 to 240 in) above the butt swell and  average about 76 m (250 ft) in height (16).

    A notable characteristic of mature giant sequoias that contributes  substantially to their great volume is the slight taper of the bole-a  feature more prominent in this species than in any other Sierra Nevada  conifer (16). In contrast, young open-grown giant sequoias taper markedly.

    The greatest known age of a giant sequoia is 3,200 years, determined  from a stump count of rings (16). Calculations based on increment borings  yield age estimates of 2,000 to 3,000 years for many living trees.

    Beyond the seedling stage, giant sequoia unhindered by an overstory  continues to grow at least as well as associated species of the same age.  In both clearcuts and group selection cuts on a high site in the central  Sierra Nevada, it has outgrown other conifers in plantations up to 18  years of age. Furthermore, giant sequoia appears less susceptible than  associated conifers to growth reductions caused by shrub competition (18).  In a survey of California plantations up to 50 years of age in which giant  sequoia had been planted, it outgrew other conifers (mostly ponderosa  pine) in most instances in which species differed significantly in height  or diameter growth. In the best plantations, giant sequoia averaged 0.5 to  0.7 m (1.6 to 2.3 ft) per year in height growth, and 1.3 to 2.0 cm (0.5 to  0.8 in) in diameter growth per year (9).

    Yields of second-growth stands dominated by giant sequoia were found to  equal or slightly exceed those of second-growth mixed-conifer stands on  the same high sites (site index 53 m [175 ft] at base age 300 years) (6).  Volumes at selected stand ages were as follows:

      Stand Age    Total volume            yr  m³/ha  fbm/acre (Scribner)      18     2.6       188      31    83.1    5,938      63  339.3  24,237      86  757.1  54,077        In cubic measure, mean annual increment at age 86 was approximately 9 m³/ha  (126 ft³/acre).

    In contrast to the brittleness and low tensile strength of the wood of  old-growth giant sequoia, young-growth trees have wood properties  comparable to those of young-growth redwood (5,28). Because most groves  have protected status, the potential of the species for fiber production  within its natural range is limited. It has been planted widely and often  successfully in many parts of the world, however. As in California  plantations, on the proper sites it outperforms most other species (7). An  80-year-old giant sequoia plantation in Belgium, for example, grew at an  average annual rate of 36 to 49 m³/ha (514 to 700 ft³/acre)  (20). Many foresters see considerable potential for giant sequoia as a  major timber-producing species of the world.

    In old-growth groves, rapid height growth continues on the better sites  for at least 100 years, producing dense conical crowns. At 400 years,  trees range in height from about 34 to 73 m (110 to 240 ft). The rate of  height growth declines beyond 400 years, and the typical tree levels off  near 76 m (250 ft) at an age of 800 to 1,500 years (17).

    Analysis of a large old-growth population showed an average d.b.h. of 48  cm (18.9 in) at 100 years, 132 cm (52.0 in) at 400 years, 219 cm (86.1 in)  at 800 years, and 427 cm (168.0 in) at 2,000 years (17).

    Although radial growth gradually decreases with age, volume increment  generally is sustained into old age. The General Sherman tree, at an  approximate age of 2,500 years, has a current radial growth rate at breast  height of about 1 mm (0.04 in) per year (16). Average volume increment for  this tree since 1931 has been estimated by different methods at 1.13 m³  (40 ft³) per year (16) and 1.44 m³ (51 ft³) per year (13).  Therefore, the world's largest tree also may be, in terms of volume  increment, the world's fastest-growing tree. A related conclusion can be  applied to the species: the enormous size attained by giant sequoia  results not only from its longevity, but also- despite the apparent  decadence of most veterans- from its continued rapid growth into old age  (16).

    Lower branches of giant sequoia die fairly readily from shading, but  trees less than 100 years old retain most of their dead branches. Boles of  mature trees generally are free of branches to a height of 30 to 45 m (98  to 148 ft) (36).

  • Burns, Russell M., and Barbara H. Honkala, technical coordinators. 1990. Silvics of North America: 1. Conifers; 2. Hardwoods.   Agriculture Handbook 654 (Supersedes Agriculture Handbook 271,Silvics of Forest Trees of the United States, 1965).   U.S. Department of Agriculture, Forest Service, Washington, DC. vol.2, 877 pp.   http://www.na.fs.fed.us/spfo/pubs/silvics_manual/table_of_contents.htm External link.
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Molecular Biology and Genetics

Genetics

Population Differences    Isolation of the groves, or populations, of giant sequoia has existed  sufficiently long for a number of population differences to become  discernible. A recent study (12) found differences among populations on  the basis of isozyme analyses, percent germination, and frequency  distribution of cotyledon numbers. Levels of heterozygosity differed  between the northern and southern parts of the range. Provenance tests in  West Germany showed differences in cold hardiness and early growth among  populations (14,20,23). Bark pattern of mature trees varies among groves  (16). Somewhat surprisingly, however, genetic variability of giant sequoia  is distinctly subdued when compared with that of other Sierra Nevada  conifers and other trees in general (21).

    Races and Hybrids    No races of giant sequoia exist (36). Fourteen horticultural forms are  known, only two of which are common (16).

    Hybridization of giant sequoia with redwood has been reported in the  Soviet Union but is unconfirmed in the western literature (19).

  • Burns, Russell M., and Barbara H. Honkala, technical coordinators. 1990. Silvics of North America: 1. Conifers; 2. Hardwoods.   Agriculture Handbook 654 (Supersedes Agriculture Handbook 271,Silvics of Forest Trees of the United States, 1965).   U.S. Department of Agriculture, Forest Service, Washington, DC. vol.2, 877 pp.   http://www.na.fs.fed.us/spfo/pubs/silvics_manual/table_of_contents.htm External link.
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Molecular Biology

Barcode data: Sequoiadendron giganteum

The following is a representative barcode sequence, the centroid of all available sequences for this species.


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Statistics of barcoding coverage: Sequoiadendron giganteum

Barcode of Life Data Systems (BOLDS) Stats
Public Records: 3
Specimens with Barcodes: 4
Species With Barcodes: 1
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Conservation

Conservation Status

IUCN Red List Assessment


Red List Category
EN
Endangered

Red List Criteria
B2ab(ii,iii,v)

Version
3.1

Year Assessed
2013

Assessor/s
Schmid, R. & Farjon, A.

Reviewer/s
Thomas, P. & Stritch, L.

Contributor/s

Justification
Despite the fact that almost all existing ‘groves’ of Sequoiadendron giganteum are in protected areas and some have been protected for more than a century, the population is in continuous decline. The actual area of occupancy, estimated to be 142 km2, falls well below the threshold for Endangered (500 km²) and with a continuing decline due to inadequate regeneration and natural death of (over)mature trees, which are being replaced by other, competing conifers, the B2 criterion applies and the species meets the criteria for listing as Endangered.

History
  • 1998
    Vulnerable
  • 1997
    Vulnerable
    (Walter and Gillett 1998)
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National NatureServe Conservation Status

United States

Rounded National Status Rank: N3 - Vulnerable

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NatureServe Conservation Status

Rounded Global Status Rank: G3 - Vulnerable

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Status

Classified as Vulnerable (VU - A1cd) on the IUCN Red List 2002 (1).
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Population

Population
The present trend in recruitment of Sequoiadendron giganteum is downwards, due to competition in the absence of periodic fires in many of the protected groves. This leads over time to a downward trend in the number of mature individuals in the population. There is at present insufficient regeneration to maintain Sequoia populations in these groves (Stephenson in Aune1992, Stephenson 1996).

Population Trend
Decreasing
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Threats

Major Threats
Although nearly all groves (or 92% of the area of occupancy) are on public land, enjoying various levels of protection, the species was previously listed as Vulnerable primarily because of historic rates of decline caused by exploitation. Present problems include fire risks, largely due to (past) management practices which tended to benefit its coniferous competitors (especially Abies) rather than the target species, and which have greatly accumulated the fuel load for future fires to burn more devastatingly (Elliott-Fisk et al.1997). Crown fires could easily spread from adjacent stands of other conifers. Genetic integrity of the small northernmost (and isolated) grove in Placer County is jeopardized by nearby plantings of S. giganteum from other sources (Elliott-Fisk et al. 1997).
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Giant sequoia forests were massively logged from the time they were first discovered in the mid 1800s until the 1950s (1). The resistant nature of the wood made it a favourable timber and it was used to make a wide variety of items from fence posts to patio furniture (2). Roughly 34% of the original range of the giant sequoia was lost to timber extraction (4). Ironically, a further threat to sequoia groves came from fire prevention strategies imposed by forest managers; this strategy prevented sequoias from regenerating successfully, whist allowing competitor species to proliferate (4).
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Management

Conservation Actions

Conservation Actions
Nearly all know ‘groves’ of this species are in protected areas; many are within famous national parks or within wilderness reserves of National Forests. There is a considerable literature on the conservation aspects of this species; for compilations see Aune (1994) and Stephenson (1996). The main conservation issue is the long absence of naturally occurring fires in the protected areas where many of the groves of Giant Sequoia occur. Different approaches to solve this problem, from controlled burning to selective logging, have been applied on different lands (burning in national parks, logging in national forests), but so far on too limited a scale to reverse the downward trend in recruitment necessary to maintain the population in the long term. More drastic measures seem to be needed, but are difficult to safely apply and/or are controversial (Elliott-Fisk et al. 1997).
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Management considerations

Insects:  Insects do not seriously harm giant sequoias older than about
2 years.  Carpenter ants (Campanotus laevigatus) do not directly harm
the trees, although they do create pathways for fungi [28].  A
wood-boring beetle (Trachykele opulenta) may kill trees damaged by road
cuts or the undercutting of stream banks.  The larvae of this beetle may
girdle a giant sequoia by feeding on the inner bark.  The cerambycid
beetle (Phymatodes nitidus) lays its larvae in green giant sequoia
cones.  Other cone larvae predators are the gelechiid moth (Gelechia
spp.) and lygaeid bug (Ischnorrhynchus resedae).  In all, 151 species of
insects and 37 arachnids are known to be associated with the giant
sequoia in that they use it to complete some part of their life cycle
[12,19,28].

Disease:  At least nine fungi have been found associated with decayed
giant sequoia wood.  The most prevalent fungi are Heterobasidion
annosum, Armillaria mellea, Poria incrassata, and P. albipellucida.
Diseases generally do not kill trees past the seedling stage directly,
but rather by contributing to root or stem failure.  No other types of
disease, including seedling disease, are known to be problems to giant
sequoia [12,19,28].

Air-pollution creating acidic mists significantly reduce root growth of
giant sequoia [25].  The development of facilities for human use, such
as paved roads and buildings, can damage giant sequoia roots and hence
slow growth [27].
  • 12.  Harvey, H. Thomas; Shellhammer, Howard S.; Stecker, Ronald E. 1980.        Giant sequoia ecology: Fire and reproduction. Scientific Monograph        Series No 12. Washington, DC: U.S. Department of the Interior, National        Park Service. 182 p.  [6587]
  • 19.  Parmeter, John R., Jr. 1986. Diseases and insects of giant sequoia. In:        Weatherspoon, C. Phillip; Iwamoto, Y. Robert; Piirto, Douglas D.,        technical coordinators. Proceedings of the workshop on management of        giant sequoia; 1985 May 24-25; Reedley, CA. Gen. Tech. Rep. PSW-95.        Berkeley, CA: U.S. Department of Agriculture, Forest Service, Pacific        Southwest Forest and Range Experiment Station: 11-13.  [9803]
  • 25.  Temple, Patrick J. 1988. Injury and growth of Jeffrey pine and giant        sequoia in response to ozone and acidic mist. Environmental and        Experimental Botany. 28(4): 323-333.  [13016]
  • 27.  Vale, Thomas R. 1975. Ecology and environmental issues of the Sierra        Redwood (Sequoiadendron giganteum), now restricted to California.        Environmental Conservation. 2(3): 179-188.  [8776]
  • 28.  Weatherspoon, C. Philip. 1990. Sequoiadendron giganteum (Lindl.)        Buchholz. In: Burns, Russell M.; Honkala, Barbara H., technical        coordinators. Silvics of North America. Volume 1. Conifers. Agric.        Handb. 654. Washington, DC: U.S. Department of Agriculture, Forest        Service: 552-562.  [13415]

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Conservation

The giant sequoia is now recognised as a national treasure and as much as 90% of the population is protected (1). The best-known groves are found in Yosemite, Sequoia and Kings Canyon National Parks (3); attracting tourists from far and wide to view these magnificent trees. The National Parks Service now practices controlled burning as part of its management strategy, although further research is needed into the natural cycle of disturbance in order to better understand these processes (4). Giant sequoias have a vital role within the Sierra Nevada ecosystem and their majesty has also provided an aesthetic and cultural role within society; thus making their future survival extremely important (6).
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Relevance to Humans and Ecosystems

Benefits

Other uses and values

Giant sequoia is planted as an ornamental inside and outside of its
native range.  It is also used for Christmas trees [28].
  • 28.  Weatherspoon, C. Philip. 1990. Sequoiadendron giganteum (Lindl.)        Buchholz. In: Burns, Russell M.; Honkala, Barbara H., technical        coordinators. Silvics of North America. Volume 1. Conifers. Agric.        Handb. 654. Washington, DC: U.S. Department of Agriculture, Forest        Service: 552-562.  [13415]

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Cover Value

More info for the term: cover

Wildlife primarily use giant sequoia for cover.  Early in giant sequoia
development, large mammals use dense stands as hiding and thermal cover.
Mature trees are used to a limited extent by arboreal species such as
birds, squirrels, and other small mammals [10].
  • 10.  Hartesveldt, Richard J.; Harvey, H. Thomas; Shellhammer, Howard S.;        Stecker, Ronald E. 1975. The sequoia of the Sierra Nevada. Washington,        DC: U.S. Department of the Interior, National Park Service. 180 p.        [4233]

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Wood Products Value

Giant sequoia was cut commercially from the 1850's up to the mid-1950's.

Young giant sequoia has favorable wood properties.  It is
decay-resistant and used as dimensional lumber, veneer, and plywood
[21].  Old growth has low tensile strength and brittleness, making it
unsuitable for most structural purposes.  The most historically popular
items milled from giant sequoia were fenceposts, grape stakes, shingles,
novelties, patio furniture, and pencils [10].
  • 10.  Hartesveldt, Richard J.; Harvey, H. Thomas; Shellhammer, Howard S.;        Stecker, Ronald E. 1975. The sequoia of the Sierra Nevada. Washington,        DC: U.S. Department of the Interior, National Park Service. 180 p.        [4233]
  • 21.  Piirto, Douglas D. 1986. Wood of giant sequoia: properties and unique        characteristics. In: Weatherspoon, C. Phillip; Iwamoto, Y. Robert;        Piirto, Douglas D., technical coordinators. Proceedings of the workshop        on management of giant sequoia; 1985 May 24-25; Reedley, CA. Gen. Tech.        Rep. PSW-95. Berkeley, CA: U.S. Department of Agriculture, Forest        Service, Pacific Southwest Forest and Range Experiment Station: 19-23.        [9806]

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Importance to Livestock and Wildlife

Only a limited number of wildlife species utilize giant sequoia for food
and shelter.

Birds:  Over 30 bird species have been identified in giant sequoia
groves.  A variety of foliage- and air-feeding birds occupy the upper
canopy, while sapsuckers feed through the thin bark.  Cavity-nesters
that use giant sequoia for nesting include white-headed woodpeckers and
flickers, and an occasional perching bird such as a nuthutch.

Mammals:  Common mammal associates include the deer mouse, chipmunk,
shrew, gray squirrel, golden-mantled ground squirrel, mule deer, coyote,
black bear, and various reptiles.  Reports of chipmunks using giant
sequoia sawdust for cleansing baths have been noted.  The chickaree is
especially noted for its relationship to giant sequoia.  Chickarees make
the soft flesh of green giant sequoia cone scales a major food item.  An
individual chickaree may cut and eat as many as 3,000 to 3,500 cones per
year [10,12].
  • 10.  Hartesveldt, Richard J.; Harvey, H. Thomas; Shellhammer, Howard S.;        Stecker, Ronald E. 1975. The sequoia of the Sierra Nevada. Washington,        DC: U.S. Department of the Interior, National Park Service. 180 p.        [4233]
  • 12.  Harvey, H. Thomas; Shellhammer, Howard S.; Stecker, Ronald E. 1980.        Giant sequoia ecology: Fire and reproduction. Scientific Monograph        Series No 12. Washington, DC: U.S. Department of the Interior, National        Park Service. 182 p.  [6587]

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Nutritional Value

The mean caloric value of giant sequoia seeds is 4,738 calories per gram
dry weight.  The outer portions of the cones provide 4,690 calories per
gram dry weight [12].
  • 12.  Harvey, H. Thomas; Shellhammer, Howard S.; Stecker, Ronald E. 1980.        Giant sequoia ecology: Fire and reproduction. Scientific Monograph        Series No 12. Washington, DC: U.S. Department of the Interior, National        Park Service. 182 p.  [6587]

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Palatability

Deer browse on 4- and 5-year-old giant sequoia; however, it is generally
considered low in palatability [10].
  • 10.  Hartesveldt, Richard J.; Harvey, H. Thomas; Shellhammer, Howard S.;        Stecker, Ronald E. 1975. The sequoia of the Sierra Nevada. Washington,        DC: U.S. Department of the Interior, National Park Service. 180 p.        [4233]

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Special Uses

Within its natural range, giant sequoia is valued primarily for esthetic  and scientific purposes. Outside this range, it is highly regarded as an  ornamental in several parts of the United States and in numerous other  countries (16). Some interest has been expressed for utilizing it in  Christmas tree plantations.

  • Burns, Russell M., and Barbara H. Honkala, technical coordinators. 1990. Silvics of North America: 1. Conifers; 2. Hardwoods.   Agriculture Handbook 654 (Supersedes Agriculture Handbook 271,Silvics of Forest Trees of the United States, 1965).   U.S. Department of Agriculture, Forest Service, Washington, DC. vol.2, 877 pp.   http://www.na.fs.fed.us/spfo/pubs/silvics_manual/table_of_contents.htm External link.
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Wikipedia

Sequoiadendron giganteum

This article is about the species commonly called "giant sequoia". For the species commonly called "coast redwood", see Sequoia sempervirens. For other uses, see Sequoia (disambiguation).

Sequoiadendron giganteum (giant sequoia, giant redwood, Sierra redwood, Sierran redwood, or Wellingtonia) 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). The common use of the name "sequoia" generally refers to Sequoiadendron giganteum which occurs naturally only in groves on the western slopes of the Sierra Nevada Mountains of California. It is named after Sequoyah (1767–1843), the inventor of the Cherokee syllabary.[2]

Description[edit]

Giant sequoias are the world's largest single trees and largest living thing by volume. Giant sequoias grow to an average height of 50–85 m (164–279 ft) and 6–8 m (20–26 ft) in diameter. Record trees have been measured to be 94.8 m (311 ft) in height and over 17 m (56 ft) in diameter.[3] The oldest known giant sequoia based on ring count is 3,500 years old. Giant Sequoias are among the oldest living things on Earth. Sequoia bark is fibrous, furrowed, and may be 90 cm (3.0 ft) thick at the base of the columnar trunk. It provides significant fire protection for the trees. The leaves are evergreen, awl-shaped, 3–6 millimetres (0.12–0.24 in) long, and arranged spirally on the shoots. The seed cones are 4–7 centimetres (1.6–2.8 in) long and mature in 18–20 months, though they typically remain green and closed for up to 20 years; each cone has 30–50 spirally arranged scales, with several seeds on each scale, giving an average of 230 seeds per cone. The seed is dark brown, 4–5 millimetres (0.16–0.20 in) long and 1 millimetre (0.039 in) broad, with a 1-millimetre (0.039 in) wide, yellow-brown wing along each side. Some seeds are shed when the cone scales shrink during hot weather in late summer, but most are liberated when the cone dries from fire heat or is damaged by insects.

Giant sequoia cones and seed

The giant sequoia regenerates by seed. Young trees start to bear cones at the age of 12 years. Trees up to about 20 years old may produce stump sprouts subsequent to injury, but unlike coast redwood, shoots do not form on the stumps of mature trees. Giant sequoias of all ages may sprout from their boles when branches are lost to fire or breakage.

At any given time, a large tree may be expected to have about 11,000 cones. Cone production is greatest in the upper portion of the canopy. A mature giant sequoia has been estimated to disperse 300,000–400,000 seeds per year. The winged seeds may be carried up to 180 metres (590 ft) from the parent tree.

Lower branches die fairly readily from shading, but trees less than 100 years old retain most of their dead branches. Trunks of mature trees in groves are generally free of branches to a height of 20–50 metres (66–164 ft), but solitary trees will retain low branches.

Biology[edit]

Because of its size the tree has been studied for its water pull. Water from the roots can be pushed up only a few meters by osmotic pressure but can reach extreme heights by using a system of branching capillarity (capillary action) in the tree's xylem (the water tubules) and sub-pressure from evaporating water at the leaves.[4] Sequoias supplement water from the soil with fog, taken up through air roots, at heights where the root water cannot be pulled to.[5]

Distribution[edit]

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 sequoias are currently undergoing a gradual decline in density since European settlement.

Ecology[edit]

Two giant sequoias, Sequoia National Park. Note the large fire scar at the base of the right-hand tree; fires do not typically kill the trees but do remove competing thin-barked species, and aid giant sequoia regeneration.

The giant sequoias 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.

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 also led to ground fuel build-up and the dense growth of fire-sensitive white fir. This increased 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. This cuts the vascular water supply to the cone scales, allowing 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.[6]

Discovery and naming[edit]

Shortly after their discovery by Europeans, giant sequoias were subject to much exhibition

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.[7] This discovery 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 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.[7] 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.[8] 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.

Clothespin tree in the Mariposa Grove, Yosemite National Park

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 J. Buchholz,[9] 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.

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?' [10]

Uses[edit]

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. 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.[citation needed]

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.

Cultivation[edit]

The well-known giant sequoia avenue at Benmore Botanic Garden, planted in 1863. These trees are all over 50 m tall.

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.

Since its discovery, a wide range of horticultural varieties have been selected, especially in Europe. There are, amongst others, weeping, variegated, pygmy, blue, grass green, and compact forms.[11]

Europe[edit]

The giant sequoia was brought into cultivation in 1853 by Scotsman John D. Matthew, who collected a small quantity of seed in the Calaveras Grove,and took it home to his noted Horticulturist father Patrick Matthew of Gourdiehill near Errol in Perth Shire arriving with it in Scotland in August 1853.[12] A much larger shipment of seed collected (also in the Calaveras Grove) by William Lobb, acting for the Veitch Nursery at Budlake near Exeter, arrived in England in December 1853;[13] 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 54 m (177 ft) at age 150 years,[14] 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. 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.

Sequoiadendron giganteum at New Forest, Hampshire, England, one of the tallest in the UK at 52.73 m (173.0 ft).[15]

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.[16]

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). The tallest specimen measured in Europe is a tree near Ribeauvillé in France, at a height of 57.7 m (189 ft).[17]

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.

Two members of the German Dendrology Society, E. J. Martin and Illa Martin, introduced the giant sequoia into German forestry at the Sequoiafarm Kaldenkirchen in 1952.[18]

Twenty-nine giant sequoias, measuring around 30 m (98 ft) in height, grow in Belgrade's municipality of Lazarevac in Serbia.[19]

The oldest sequoiadendron in the Czech Republic, at 44 m (144 ft), grows in Ratměřice u Votic castle garden.

United States and Canada[edit]

Unopened pollen (male) cones of cultivated tree in Portland, Oregon, USA (fall)
Immature seed (female) cones of cultivated tree in Portland, Oregon, USA (fall)

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 (over 90 feet) are fairly common and exist in several city parks and many private yards (especially east Seattle including Capitol Hill, Washington Park, & Leschi/Madrona).

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.[20][21] The tree at the Tyler Arboretum in Delaware County, Pennsylvania at 29.1 metres (95 ft) may be the tallest in the northeast.[22] 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. Since 2000, a small amateur experimental planting has been underway in the Lake Champlain valley of Vermont at the Vermont Experimental Cold-Hardy Cactus Garden where winter temperatures can reach −37 °C with variable snowcover. A few trees have been established in Colorado as well.[23] Additionally, numerous sequoias have been planted with success in the state of Michigan.[24]

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.

Australia[edit]

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 2 specimens which were planted in the early 1860s.[25] In Tasmania specimens are to be seen in private and public gardens, as they were popular in the mid Victorian era. The Westbury Village Green has mature specimens with more in Deloraine. The Tasmanian Arboretum contains young wild collected material. The National Arboretum Canberra has begun a grove. They also grow in the abandoned arboretum at Mount Banda Banda in New South Wales.

New Zealand[edit]

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 Queenstown.[26] There is also a tree at Rangiora High School, which was planted for Queen Victoria's Golden Jubilee and is thus over 125 years old.[27]

Superlatives[edit]

Largest by trunk volume[edit]

General Sherman, largest known living single stem tree in the world

Some sequoias, such as the Mother of the Forest, were undoubtedly far larger than any living tree today.[citation needed] However, as of 2009, the top ten largest giant sequoias sorted by volume of their trunks are:[3][note 1]

RankTree NameGroveHeightGirth at groundVolume
  (ft)(m)(ft)(m)(ft³)(m³)
1General ShermanGiant Forest274.983.8102.631.352,5081,486.9
2[note 2]General GrantGeneral Grant Grove268.181.7107.532.846,6081,319.8[note 2]
3[note 2]PresidentGiant Forest240.973.493.028.345,1481,278.4[note 2]
4LincolnGiant Forest255.878.098.330.044,4711,259.3
5StaggAlder Creek Grove243.074.1109.033.242,5571,205.1
6BooleConverse Basin268.881.9113.034.442,4721,202.7
7GenesisMountain Home Grove253.077.185.326.041,8971,186.4
8FranklinGiant Forest223.868.294.828.941,2801,168.9
9King ArthurGarfield Grove270.382.4104.231.840,6561,151.2
10MonroeGiant Forest247.875.591.327.840,1041,135.6
  • The General Sherman tree is estimated to weigh about 2100 tonnes.[30]
  • 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.

Tallest[edit]

Oldest[edit]

The Muir Snag, believed to be over 3500 years old

Greatest girth[edit]

  • Waterfall Tree - Alder Creek Grove - 47 metres (155 ft) - tree with enormous basal buttress on very steep ground.[3]

Greatest base diameter[edit]

  • Waterfall Tree - Alder Creek Grove - 21 metres (69 ft) - tree with enormous basal buttress on very steep ground.[3]
  • Tunnel Tree - Atwell Mill Grove - 17 metres (57 ft) - tree with a huge flared base that has burned all the way through.[3]

Greatest mean diameter at breast height[edit]

Largest limb[edit]

Thickest bark[edit]

  • 0.9 metres (3 ft) or more[3]

See also[edit]

Notes[edit]

  1. ^ 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.
  2. ^ a b c d 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.[28][29] 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.[28][29] General Sherman has 2,000 cubic feet (57 m3) more wood than the President tree.[28]

References[edit]

  1. ^ Schmid, R. & Farjon, A. 2013. Sequoiadendron giganteum. In: IUCN 2013. IUCN Red List of Threatened Species. Version 2013.1. <www.iucnredlist.org>. Downloaded on 13 July 2013.
  2. ^ Sierra Nevada - The Naturalist's Companion. University of California Press. 1 June 2000. p. 55. ISBN 978-0-520-92549-6. 
  3. ^ a b c d e f g h i j Flint 2002
  4. ^ water pull at Cropsview (an agriculture science magazine) website
  5. ^ Studies on tree height limits, and the Sequoia in particular
  6. ^ Hartesveldt, RJ; Harvey, HT (1967). "The Fire Ecology of Sequoia Regeneration". Tall Timbers Fire Ecology Conference 7: 7. 
  7. ^ a b Farquhar, Francis P. (1925). "Discovery of the Sierra Nevada". California Historical Society Quarterly 4 (1): 3–58. doi:10.2307/25177743. , Yosemite.ca.us
  8. ^ Ornduff, R. (1994). "A Botanist's View of the Big Tree". In Aune, P. S. Proceedings of the Symposium on Giant Sequoias. US Dept. of Agriculture Forest Service (Pacific Southwest Research Station). General Technical Report PSW-GTR-151. 
  9. ^ Buchholz, J. T. (1939). "The Generic Segregation of the Sequoias". American Journal of Botany 26 (7): 535–538. doi:10.2307/2436578. JSTOR 2436578. 
  10. ^ Muir, John (November 1996). Gifford, Terry, ed. John Muir: His Life and Letters and Other Writings. Mountaineers Books. pp. 139–140. ISBN 0898864631. 
  11. ^ "Species Level Browse Results". NurseryGuide.com. Archived from the original on 2012-07-07. 
  12. ^ "The History of Cluny – The Plant Collectors". clunyhousegardens.com. Retrieved 23 December 2008. 
  13. ^ Christopher J. Earle. "Sequoiadendron giganteum (Lindley) Buchholz 1939". University of Hamburg. Retrieved 23 December 2008. 
  14. ^ Tree Register of the British Isles, tree-register.org
  15. ^ "Top Trunks". Redwood World. Retrieved September 19, 2013. 
  16. ^ "Sequoie d'Italia". Retrieved January 22, 2014. 
  17. ^ "Giant sequoia in the forêt domaniale de Ribeauvillé". monumentaltrees.com. Retrieved September 18, 2013. 
  18. ^ 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
  19. ^ Puzović, B. (August 15, 2011). "Lazarevac: Visoke sekvoje niču iz uglja" (in Serbian). Novosti.rs. Retrieved September 17, 2013. 
  20. ^ "Mansion and History". Blithewold Mansion, Gardens, and Arboretum. 
  21. ^ "Gardens". Blithewold Mansion, Gardens, and Arboretum. 
  22. ^ Big Trees Of Pennsylvania: Sequoiadendron - Giant Sequoia, pabigtrees.com
  23. ^ "Colorado giant sequoia". giant-sequoia.com. 
  24. ^ Michigan giant sequoia - Giant Sequoia
  25. ^ Jamieson & District Historical Society
  26. ^ Sphaydenphotography.com
  27. ^ Rangiora High School | History
  28. ^ a b c Cone, Tracie (2012-12-01). "Upon further review, giant sequoia tops a neighbor". Associated Press. 
  29. ^ a b Quammen, David. "Giant Sequioas". National Geographic. 
  30. ^ Fry & White 1938

Further references[edit]

Further reading[edit]

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Notes

Comments

Mature individuals of this species are the most voluminous living organisms and among the most long-lived trees. Sequoiadendron giganteum was formerly included in Sequoia , under the later homonym Sequoia gigantea (Lindley) Decaisne, a conservative placement that still has merit (J. Doyle 1945; O. Schwarz and H. Weide 1962). 

 Redwood, including Sequoiadendron giganteum and Sequoia sempervirens , is the state tree of California.

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© Missouri Botanical Garden, 4344 Shaw Boulevard, St. Louis, MO, 63110 USA

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In the wild, this tree can reach an age of 3500 years.
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Names and Taxonomy

Taxonomy

Common Names

giant sequoia
bigtree

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The currently accepted scientific name for giant sequoia is
Sequoiadendron giganteum (Lindl.) Buchholz [26,28]. There are no
recognized subspecies, varieties, or forms.
  • 26.  U.S. Department of Agriculture, Soil Conservation Service. 1982.        National list of scientific plant names. Vol. 1. List of plant names.        SCS-TP-159. Washington, DC. 416 p.  [11573]
  • 28.  Weatherspoon, C. Philip. 1990. Sequoiadendron giganteum (Lindl.)        Buchholz. In: Burns, Russell M.; Honkala, Barbara H., technical        coordinators. Silvics of North America. Volume 1. Conifers. Agric.        Handb. 654. Washington, DC: U.S. Department of Agriculture, Forest        Service: 552-562.  [13415]

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Synonyms

Sequoia gigantea (Lindl.) Buchholz

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