Giant Sequoia Description Distribution Reproduction

The Giant Sequoia (Sequoiadendron giganteum) is one of a number of species of coniferous trees known as redwoods, classified in the family Cupressaceae in a part of this family formerly segregated as the Taxodiaceae.

1 Description

Giant Sequoia is the world's largest tree in terms of total volume. They grow to an average height of 70-85 m (230-280 ft) and 5-7 m (16-23 ft) in diameter. Record trees have been reported to be 93.6 m (307 ft) in height and 8.85 m (29 ft) in diameter. The oldest known Giant Sequoia based on ring count is 3,200 years old. Sequoia bark is fibrous, furrowed, and may be 60 cm (2 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 mm long, and arranged spirally on the shoots. The seed cones are 4-7 cm long and mature in 18-20 months, though they may remain green up to 20 years.

Giant Sequoia regenerates primarily by seed, although occasionally it may reproduce naturally by vegetative methods; trees up to about 20 years old 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, but (unlike the related Coast RedwoodThe Coast Redwood or California Redwood Sequoia sempervirens is an evergreen, long-lived, monoecious tree in the family Cupressaceae. It is the tallest tree in the world, reaching up to 112 m in height, and 7 m diameter at the base. The oldest known Coast) mature trees do not sprout from cut stumps. Young trees start to bear cones at the age of 20 years. Cones may remain attached to the tree for 8-20 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.

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 300,000-400,000 seeds per year. The winged seeds may be carried up to 180m (600 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 generally are free of branches to a height of 30-40 m (100-150 ft).

2 Distribution

Giant Sequoia is usually found in a humid climate characterized by dry summers and snowColorado's, ( USA) high forests. Snow is precipitation in the form of crystalline water ice, consisting of a multitude of snowflakes. Since it is composed of small rough particles it is a granular material. It has an open and therefore soft structure, unly winters. Most Giant Sequoia groves are on granitic-based residual and alluvial soils. The elevation of the Giant Sequoia groves generally ranges from 1,400-2,000m (4,600-6,600 ft) in the north, and 1,700-2,150 m (5,600-7,000 ft) to the south. Giant Sequoia generally appears on southern slopes in its northern distribution and on more northerly slopes in the south.

The natural distribution of Giant Sequoia is restricted to along a limited area of the western Sierra NevadaThe Sierra Nevada is a mountain range that is mostly in eastern California. The range is also known as The Sierra . Geography The Sierra Nevada stretches 400 miles (650km), from Fredonyer Pass in the North to Tehachapi Pass in the South. The Sierra Nevada, CaliforniaCalifornia is a state located in the western United States, bordering the Pacific Ocean. The most populous and third largest state in the U. California is both physically and demographically diverse. The state's official nickname is "The Golden State", wh. It occurs in scattered groves, with a total of 65-76 groves (see list of sequoia grovesThe following is a list of Giant Sequoia groves . All groves are located in moist, unglaciated ridges and valleys of the west slope of the Sierra Nevada range in California, USA. They occur between 1370-2000 m (4500-6500 ft) altitude in the northern half for a full inventory), comprising a total area of only 14,416 ha (144.16 km² / 35,607 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 RiverThe American River in California is known for its whitewater rapids, and as the location of Sutter's Mill (where gold was found, leading to the California Gold Rush). It runs from the Sierra Nevada mountains through Sacramento and flows into the Sacrament in Placer CountyPlacer County is a county located in California's Sierra Nevada, in the Gold Country. It stretches from the suburbs of Sacramento to Lake Tahoe and the Nevada border. Because of the expansion of the Sacramento metropolitan area, Placer County is one of th southward to the Kings RiverThe Kings River is a major river of California, USA. It arises in the Sierra Nevada, in three forks. The Middle and South fork start in Kings Canyon National Park, while the North fork starts in the John Muir Wilderness. The South fork flows in Kings Cany, 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 1,240ha (3,100 acres) with 20,000 mature trees, to small groves with only six living trees.

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.

3 Reproduction

Giant Sequoia cones. See also:, Sugar Pine

Even though these trees are the largest in the world, their cones and seeds are small (see photo). These seeds can only germinate in mineral soils and possibly only soils derived from metamorphic rock. Periodic fire to clear competing vegetation, large amounts of water, and the climatic conditions that exist at 1,500-2,400 m altitude in the Sierra Nevada are important for regeneration. Without fire, shade-loving species will crowd out young sequoia seedlings, and sequoia seeds will not germinate. When full grown, these trees typically require large amounts of water and are therefore often concentrated near streams.

The Giant Sequoias are having difficulty reproducing in their original habitat. They are trees that historically depend on periodic fires for regeneration. Sequoia seeds germinate and grow best in open mineral soils with minimal forest litter. Such soils are produced by low-intensity ground fires. Furthermore, Giant Sequoia are more likely to release seeds due to hot air caused by a fire. Due to fire suppression efforts and livestock grazing during the 20th Century, low-intensity fires no longer occur naturally.

4 Other names

Until 1939, the Giant Sequoia was classified in the same genus as the Coast Redwood, as Sequoia gigantea, though this name was invalid under the botanical code, having been applied first (in 1847) to the Coast Redwood and only later (in 1854) to the Giant Sequoia. The nomenclatural oversight was corrected by botanist J. Buchholz , who also pointed out that the Giant Sequoia is distinct from the Coast Redwood at the genus level and coined the name Sequoiadendron for it. In Britain it was also sometimes called Wellingtonia, though this name is also invalid, correctly belonging to the tropical southeast Asian broadleaf tree Wellingtonia arnottiana in the family Sabiaceae . Other vernacular names include Sierra Redwood, Giant Redwood, or simply the Big Tree.

5 List of the ten largest Giant Sequoias

As of December 2002, the 10 largest trees (by volume) are:

Tree Name	Location	Height		Circumference		Volume
		(m)	(ft)	(m)	(feet)	(m³)	(ft³)
General Sherman	Giant Forest	83.79	274.9	31.27	102.6	1486.9	52,508
Washington	Giant Forest	77.63	254.7	30.82	101.1	1355.0	47,850
General Grant	Grant Grove	81.72	268.1	32.77	107.5	1319.8	46,608
President	Giant Forest	73.43	240.9	28.35	93.0	1278.4	45,148
Lincoln	Giant Forest	77.97	255.8	29.96	98.3	1259.3	44,471
Stagg	Alder Creek	74.07	243.0	33.22	109.0	1205.0	42,557
Boole	Converse Basin	81.93	268.8	34.44	113.0	1202.7	42,472
Genesis	Mountain Home	77.11	253.0	26.00	85.3	1186.4	41,897
Franklin	Giant Forest	68.21	223.8	28.90	94.8	1168.9	41,280
King Arthur	Garfield	82.39	270.3	31.76	104.2	1151.2	40,656

Source: US National Park Service - [1]. Note that the volume figures have a low degree of accuracy, 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, e.g., the 35 m deep, 3 m diameter cavity recently discovered in the Washington tree, accessible only by a hole situated 58 m above the ground. The measurements are however trunk-only, and do not include the volume of wood in the branches or roots.

6 Giant Sequoia in cultivation

Giant Sequoia is a popular ornamental tree in many areas. It was first brought into cultivation in 1853, when a large shipment of seed arrived in Britain, collected in the Calaveras Groves (now in Calaveras Big Trees State Park). Growth in Britain is very fast, with the tallest tree, at Benmore in southwest Scotland, reaching 54m at age 150 years (Tree Register of the British Isles), and several others from 50-53m tall; the stoutest is 3.55m diameter, in Perthshire. Other areas where it is successfully grown include most of western and southern Europe, the Pacific Northwest of North America north to at least Vancouver, southeast Australia, New Zealand and central-southern Chile. Growth rates in some areas are remarkable; one young tree in Italy reached 22m tall and 88 cm trunk diameter in 17 years.

In the northeastern USA 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 humid summer climate there. The tallest reported in the east is one just over 30m tall, at Manistee in Michigan. A recently selected disease-resistant and cold tolerant cultivar 'Hazel Smith' is proving more successful in that area. This clone was the sole survivor of several thousand seedlings grown at a nursery in New Jersey.

7 Reference

Aune, P. S. (ed.) 1994. Proceedings of the Symposium on Giant Sequoias. US Dept. of Agriculture Forest Service (Pacific Southwest Research Station) General Technical Report PSW-GTR-151.

8 External links

Cupressaceae Sierra Nevada

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