   #copyright

Sequoia

2007 Schools Wikipedia Selection. Related subjects: Plants

                    iSequoia sempervirens
   Sequoia sempervirens in Redwood National and State Parks
   Sequoia sempervirens in Redwood National and State Parks

                             Conservation status

   Vulnerable (VU)
                  Scientific classification

   Kingdom:  Plantae
   Division: Pinophyta
   Class:    Pinopsida
   Order:    Pinales
   Family:   Cupressaceae
   Genus:    Sequoia
   Species:  S. sempervirens

                                Binomial name

   Sequoia sempervirens
   ( D. Don) Endl.

   Sequoia is a genus in the cypress family Cupressaceae, containing the
   single living species Sequoia sempervirens. Common names include Coast
   Redwood and California Redwood (it is one of three species of trees
   known as redwoods). It is an evergreen, long-lived, monoecious tree
   living for up to 2,000 years, and is commonly considered the tallest
   tree in the world, reaching up to 115.5 m (378 ft) in height and 7 m
   (23 ft) diameter at the base. It is thought to be named after the
   Cherokee Indian leader, Sequoyah, though this is uncertain.

   The name Sequoia is also used as a general term for the subfamily
   Sequoioideae in which this genus is classified together with
   Sequoiadendron (Giant Sequoia) and Metasequoia (Dawn Redwood).
   Detail: bark
   Enlarge
   Detail: bark

   The crown is conical, with horizontal to slightly drooping branches.
   The bark is very thick, up to 30 cm (12 in), and quite soft, fibrous
   with a bright red-brown when freshly exposed (hence the name
   'redwood'), weathering darker. The root system is composed of shallow,
   wide-spreading lateral roots. The leaves are variable, being 15-25 mm
   long and flat on young trees and shaded shoots in the lower crown of
   old trees, and scale-like, 5-10 mm long on shoots in full sun in the
   upper crown of older trees; there is a full range of transition between
   the two extremes. They are dark green above, and with two blue-white
   stomatal bands below. Leaf arrangement is spiral, but the larger shade
   leaves are twisted at the base to lie in a flat plane for maximum light
   capture. The seed cones are ovoid, 15-32 mm long, with 15-25 spirally
   arranged scales; pollination is in late winter with maturation about
   8-9 months after. Each cone scale bears 3-7 seeds, each seed 3-4 mm
   long and 0.5 mm broad, with two wings 1 mm wide. The seeds are released
   when the cone scales dry out and open at maturity. The pollen cones are
   oval, 4-6 mm long. The species is monoecious, with pollen and seed
   cones on the same plant. Its genetic makeup is unusual among conifers,
   being a hexaploid (6n) and likely autoallopolyploid (AAAABB). The
   mitochondrial genome is (unlike other conifers) paternally inherited
   (Neale et al. 1989).

Range and ecology

   Fog is of major importance in Coast Redwood ecology. Redwood National
   Park.
   Enlarge
   Fog is of major importance in Coast Redwood ecology. Redwood National
   Park.

   Coast Redwoods occupy a narrow strip of land approximately 750 km (470
   miles) in length and 8-75 km (5-47 miles) in width along the Pacific
   coast; the elevation range is mostly from 30-750 m, occasionally down
   to sea level and up to 920 m (Farjon 2005). They usually grow in the
   mountains where there is more precipitation from the incoming moisture
   off the ocean. The tallest and oldest trees are found in deep valleys
   and gullies, where year-round streams can flow, and fog drip is
   regular. The trees above the fog layer, above about 700 m, are shorter
   and smaller due to the drier, windier, and colder conditions. In
   addition, tanoak, pine and Douglas-fir often crowd out redwoods at
   these elevations. Few redwoods also grow close to the ocean due to
   intense salt spray, sand and wind.

   The northern boundary of its range is marked by two groves on the
   Chetco River on the western fringe of the Klamath Mountains, 25 km (15
   miles) north of the California-Oregon border. The largest populations
   are in Jedediah Smith Redwoods State Park ( Del Norte County), Redwood
   National Park and Humboldt Redwoods State Park ( Humboldt County). The
   furthest inland are 75 km from the sea, in Napa County. The southern
   boundary of the range is marked by a grove in Salmon Creek Canyon in
   the Santa Lucia Mountains of southern Monterey County.

   This native area provides a unique environment with heavy seasonal
   rains (2500 mm or 100 in annually), cool coastal air and fog keeping
   this forest constantly damp year round. As this heavy rain has left the
   soil with few nutrients, these trees depend on the entire biotic
   community of the forest, and complete recycling of the trees when dead.
   Logging interrupts this process. This forest community includes
   Douglas-fir, Western Hemlock, Tanoak, Madrone, and other trees along
   with a wide variety of ferns, Redwood sorrel, mosses and mushrooms.
   Redwood forests provide habitat for a variety of mammals, birds,
   reptiles, and amphibians. Remnant old growth redwood stands provide
   habitat for the federally threatened Spotted Owl and the
   California-endangered Marbled Murrelet.

   The thick, tannin-rich bark, combined with foliage that starts high
   above the ground provides good protection from both fire and insect
   damage, contributing to the Coast Redwood's longevity. The oldest known
   Coast Redwood is about 2200 years old; many others in the wild exceed
   600 years.

   The prehistoric fossil range of the genus is considerably greater, with
   a subcosmopolitan distribution including Europe and Asia until about 5
   million years ago.

Statistics

   Trees over 60 m (200 feet) are common, and many are over 90 m (300
   feet).
     * The current tallest tree is Hyperion, measuring at 115.55 m (379.1
       feet). The tree was discovered in Redwood National Park during
       Summer 2006 by Chris Atkins and Michael Taylor and has been
       measured as the world's tallest living thing. The previous record
       holder was the Stratosphere Giant in the Humboldt Redwoods State
       Park, at 112.83 m, last measured in 2004 (was 112.34 m in Aug 2000
       and 112.56 m in 2002). Until it fell in March 1991, the "Dyerville
       Giant" was the record holder. It too stood in Humboldt Redwoods
       State Park; it was 113.4 metres high and estimated to be 1600 years
       old.
     * There are 15 known living trees more than 110 m (361 feet) tall.
     * There are 47 trees that are more than 105 m (344.5 feet) tall.
     * A tree claimed to be 115.8 m (380 feet) was cut down in 1912.
     * The tallest non-redwood tree is a 100.3 m (329 foot) tall
       Douglas-fir.

   In 2004, an article in Nature reported that the theoretical maximum
   potential height of Coast Redwoods (or any other tree) is limited to
   between 122-130 m (400-425 feet), due to gravity and the friction
   between water and the vessels through which it flows.

   The largest in volume is the "Del Norte Titan", with an estimated
   volume of 1044.7 m³; it is 93.57 m tall with a diameter of 7.22 m.
   Among current living trees only 15 Giant Sequoias are larger than this;
   these are shorter, but have thicker trunks, giving the largest Giant
   Sequoia, General Sherman, a volume of 1,487 cubic metres (52,510 cubic
   feet). A redwood cut down in 1926 had a claimed volume of 1,794 cubic
   metres (63,350 cubic feet), but this is not verified.

Reproduction

   This is an example of a "fairy ring" sprouted from a stump. All the
   sprouts are identical clones with exactly the same genomic material.
   Enlarge
   This is an example of a "fairy ring" sprouted from a stump. All the
   sprouts are identical clones with exactly the same genomic material.

   Coast Redwood reproduces both sexually and asexually. Seed production
   begins at 10-15 years of age, and large seed crops occur frequently,
   but viability of the seed is low, typically below 20%. The low
   viability may be an adaptation to discourage seed predators, which do
   not want to waste time sorting chaff (empty seeds) from edible seeds.
   The winged seeds are small and light, weighing 3.3-5 mg (200-300
   seeds/g; 5600-8500/ounce). The wings are not effective for wide
   dispersal, and seeds are dispersed by wind an average of only 60-120 m
   (200-400 feet) from the parent tree.
   Coast Redwood, Redwood National Park.
   Enlarge
   Coast Redwood, Redwood National Park.

   Growth of seedlings is very fast, with young trees known to reach 20 m
   tall in 20 years. Coast Redwoods can also reproduce asexually by
   layering or sprouting from the root crown, stump, or even fallen
   branches; if a tree falls over, it will regenerate a row of new trees
   along the trunk. This is the reason for many trees naturally growing in
   a straight line. Sprouts originate from dormant or adventitious buds at
   or under the surface of the bark. The dormant sprouts are stimulated
   when the main adult stem gets damaged or starts to die. Many sprouts
   spontaneously erupt and develop around the circumference of the tree
   trunk. Within a short period after sprouting, each sprout will develop
   its own root system, with the dominant sprouts forming a ring of trees
   around the parent root crown or stump. This ring of trees is called a
   "fairy ring". Sprouts can achieve heights of 2.3 m (8 feet) in a single
   growing season.

   Redwoods may also reproduce using burls. A burl is a woody lignotuber
   that commonly appears on a redwood tree below the soil line, though
   when above, usually within 3m of the soil. Burls are capable of
   sprouting into new trees when detached from the parent tree, though
   exactly how this happens is yet to be studied. Shoot clones commonly
   sprout from burls and are often turned into decorative hedges when
   found in suburbia.

   The species is very tolerant of flooding and flood deposits, the roots
   rapidly growing into thick silt deposits after floods.

Cultivation and uses

   Tourist use of Coast Redwood by a private owner, Leggett, California.
   Enlarge
   Tourist use of Coast Redwood by a private owner, Leggett, California.
   Coast Redwood plantation at Polipoli, Hawaii.
   Enlarge
   Coast Redwood plantation at Polipoli, Hawaii.

   Coast Redwood is one of the most valuable timber species in California,
   with 364,000 ha of redwood forest, all second growth, managed for
   timber production . Coast Redwood lumber is highly valued for its
   beauty, light weight, and resistance to decay. It is also resistant to
   fire since it does not burn well due to its lack of resin.

   P. H. Shaughnessy, Chief Engineer of the San Francisco Fire Department
   wrote:

          In the recent great fire of San Francisco, that began April
          18th, 1906, we succeeded in finally stopping it in nearly all
          directions where the unburned buildings were almost entirely of
          frame construction and if the exterior finish of these buildings
          had not been of redwood lumber, I am satisfied that the area of
          the burned district would have been greatly extended.

   Redwood burls are used in the production of table tops, veneers, and
   turned goods. The phenolics and tannins present in old growth redwood
   stock affords excellent termite and water damage protection. Old growth
   redwood construction is highly prized as a result. Only 3 percent of
   the present redwood forest is old growth, but not all of it is
   protected from further exploitation. The Pacific Lumber Company, a
   subsidiary of the Maxxam Corporation, continues to log old growth
   Redwoods despite decades of public protest. More and more of the second
   growth forest is being converted into protected areas with hopes of
   them taking on old growth forest characteristics. Examples of this are
   the Big Basin State Park and the recently acquired San Lorenzo River
   Redwoods. Some of the remaining forest consists of redwood plantations
   grown on a short (40-70 years) rotation. Other areas are slowly
   succumbing to suburban sprawl.

   The Coast Redwood is locally naturalized in New Zealand, notably at
   Rotorua. Other areas of successful cultivation outside of the native
   range include western Europe from the British Isles south to Portugal,
   the Queen Charlotte Islands, middle elevations of Hawaii, and the
   southeastern United States from eastern Texas to North Carolina.
   Retrieved from " http://en.wikipedia.org/wiki/Sequoia"
   This reference article is mainly selected from the English Wikipedia
   with only minor checks and changes (see www.wikipedia.org for details
   of authors and sources) and is available under the GNU Free
   Documentation License. See also our Disclaimer.
