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Despite the general belief that giant sequoia wood is not especially
flammable, it burns hotly when splintered and dry [10].

More info for the terms: basal area, density, duff, fire severity, forest, fuel, fuel moisture, litter, prescribed fire, severity, 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 headfires 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].

Summer prescribed fires (19 August-11 September 1969) promoted giant sequoia
seedling establishment in a giant sequoia-mixed-conifer forest in Kings Canyon
National Park. The summer fires burned at moderate to high severities. They
also reduced the density of white fir and incense-cedar realative to giant
sequoia and sugar pine. Favorable establishment of giant sequoia seedlings
was related to both parent tree density and fire severity. Giant sequoia
seedling densities exceeded 40,000/acre (99,000/ha) severly burned plots.
Kilgore [30] suggested that under similar fire weather conditions, follow-up
prescribed fire would be needed 7 to 10 years later. For further information,
see the Research Project Summary of Kilgore and others' study.

giant sequoia
bigtree

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].

More info for the terms: cone, seed, 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].



Giant sequoia cone and needles. Creative Commons image by Tom DeGomez, University of Arizona, Bugwood.org.

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].



Giant sequoia distribution. Map courtesy of USDA, NRCS. 2018. The PLANTS Database.
National Plant Data Team, Greensboro, NC [26].

More info for the terms: climax, fire regime, forest, 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].

FIRE REGIMES :
Find fire regime information for the plant communities in which this
species may occur by entering the species name in the FEIS home page under
"Find FIRE REGIMES".

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

Restoration of historical stand structure and FIRE REGIMES is need if giant
sequoia and other mixed-conifer forests are to continue through millennia to come.
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].

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More info for the term: phanerophyte

Phanerophyte

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].

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

   K005  Mixed conifer forest

More info for the terms: cover, prescribed fire, 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].



Prescribed fire in a giant sequoia grove in Kings Canyon National Park. US Park Service image.

More info for the term: cone

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].

More info for the terms: forest, 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]

More info for the term: tree

Tree

More info for the term: cone

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].

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].

     CA

Giant sequoia is planted as an ornamental inside and outside of its
native range.  It is also used for Christmas trees [28].

Deer browse on 4- and 5-year-old giant sequoia; however, it is generally
considered low in palatability [10].

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More info for the terms: cone, seed

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].

More info for the term: prescribed burn

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].

More info for the term: seed

   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

More info for the terms: cone, monoecious, seed, 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].

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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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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].

Sequoia gigantea (Lindl.) Buchholz

The scientific name of giant sequoia is Sequoiadendron giganteum (Lindl.)
Buchholz [26,28]. There are no recognized subspecies, varieties, or forms.

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

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].