sequoia



sequoia defined in 1944 year

sequoia - Sequoia;
sequoia - Within the genus Sequoia, Endl. (Family Taxodiacea), are grouped two great trees of dissimilar foliage, but agreeing well in most other respects. The name commemorates a chief of the American Indians, who devised a written language for his people; he was not, however, a native of the region where these trees are found. The Sequoias are confined to the Californian region of North America, although in the not far remote past of geologists (Eocene times) they were widespread across the northern hemisphere, where their fossil remains may still be found. As the age of a Sequoia may exceed 2,000 years, this does not represent very many generations for these trees.

At the present time the Sequoias are amongst the tallest, and undoubtedly the largest and heaviest, trees in the world; heights well in excess of 300 feet have frequently been recorded. Amongst broad-leaved trees, such heights are only approached by the Eucalyptus trees of Australia, but these are a genus of more recent origin which may still be evolving towards greater height growth. The only conifer which may perhaps exceed the Sequoias in height is the Douglas Fir, but its stem is more slender and its volume consequently less. A single stem of Sequoia may contain 30,000 cubic feet of timber - more than is usually found on five acres of a good coniferous plantation. Such a stem weighs over 500 tons and is the biggest, and perhaps the oldest, living organism on earth.

The trunks of Sequoias have a strong taper, looking almost conical at their base. Their bark is extremely thick, fibrous, and spongy, and red-brown in colour; a curious feature about it, is that it absorbs a hard blow with the fist without injury to the striker. These two features enable the grown trees to be readily identified. In very old trees buttresses are developed to support the trunk, an unusual feature in conifers. The branches are pendulous, producing a regular conical crown even when the trees are open grown, and making them valuable subjects for landscape planting.

The male flowers are borne in small compact catkins; the female flowers, on the same tree, are globular bodies appearing at the tips of the branches. They ripen in one season into peculiar globular cones with thick fleshy scales, hanging from the branches and releasing tiny seeds surrounded by a membranous wing. The seedlings have few cotyledons (2 to 5) and their early leaves are spirally placed on an erect axis. In a state of nature, reproduction by seed is effective, but. one species, the Redwood, also replaces losses by coppice shoots from the fallen trunk. Under cultivation, propagation by cuttings is practicable, though not easy.

A moist and equable climate is essential to the successful growth of Sequoias, but under such conditions they make rapid headway and, although only planted in Britain during the past hundred years, heights in excess of 140 feet have already been attained. The timber of Sequoias is durable and resistant to fire, a useful quality in a building timber; it is a poor fuel wood. Another useful quality is its fissility; it is readily split into thin planks, and "shingles" prepared in this way are a popular roofing material in North America. The heartwood is red in colour, the sapwood white, and the timber is light, strong, has good working qualities, and is a valuable article of commerce.

The Californian Redwood (Sequoia semperviretts, Endl.), G. Küstensequoie, is distinguished by its needle-like foliage, which resembles that of the Yew tree or die Silver Fir, the normal foliage needles being arranged in two ranks on either side of the shoot. At intervals on these shoots, there are seen the woody, persistent scales of old winter buds, each constriction corresponding with a winter's resting period.

On leading and cone-bearing shoots, the needles are shorter and are spirally ranged. The base of each needle is adpressed to the shoot, and the needles point forwards at an angle of about 45 degrees, being closely ranked together; these features distinguish the Redwood from similar conifers, as does the minute bud, with sharp-pointed scales, which is often concealed by the developing needles.

The Redwood is the dominant tree over a large area of the Californian foothills, in a moist coastal climate at low altitudes. Enormous quantities of its valuable timber are cut and converted each year, but owing to its power of coppicing from stools, besides natural regeneration from fallen seed, the natural forests are unlikely to diminish, particularly as planting is now being resorted to, to make up deficiencies. The tree's thick bark gives it a degree of protection against forest fire, and yields a useful fibre.

The Redwood has been largely planted as an ornamental tree in Britain, and has thriven very well along the western seaboard, particularly in deep valleys with rich soil. It is reputed to be susceptible to damage by high winds, but as specimens are usually isolated and outgrow everything around them, damage of this kind is more frequent than would be the case in forests or plantations. The trunk is wind-firm; the tree is apt to suffer from frost in its early stages; it demands full light but casts a dense shade; natural enemies are few. Heights over 140 feet; girths over 24 feet, occur in Britain.

As a timber tree, Redwood should prove outstanding in Britain; plantations are still on an experimental scale, but timber from specimen trees is satisfactory apart from faults inherent in its mode of growth, where side-branches cannot be suppressed and too rapid expansion leads to a soft and open-grained type of timber. The range of sites suited to it is limited, but includes mountainous country well adapted for afforestation.

The Big Tree (Sequoia gigantea, Torrey), G. Mammutbaum, Riesensequoie; Wellingtonia, Washingtonia or Mammoth Tree, is at once distinguished from the Redwood by its foliage, the leaves being scale-like, and spirally ranged around the shoots. These leaves are clearly of very primitive type, and resemble the " juvenile " foliage of the Cypresses, which those trees speedily outgrow. In this way the Cypresses show their descent from the Big Tree, or something very like it, according to the theory of Evolutionary Recapitulation, by which young organisms tend to resemble their remote ancestors. The only conifer with foliage resembling that of the Big Tree is the Japanese Cedar, which normally has much longer leaves. The buds of the" Big Tree are small and inconspicuous and concealed by the developing scale-leaves; they leave little or no trace of their existence on the shoot, which is of continuous even growth and expansion.

In a state of nature the Big Tree is confined to a few small isolated groves in the-Sierra Nevada of California, and is so rare that despite its size it was not discovered until 1841, by John Bidwill. Owing to its rarity, the few trees existing are protected by the United States Government, and it is not exploited on any scale for its timber. At the southern end of its range it reproduces itself freely, but farther north its numbers appear to be decreasing, showing perhaps how its spread throughout the world has gradually been restricted by changes in climate to which it has been unable to adapt itself. Its present altitude range varies from 4,000 to 8,000 feet above sea-level.

Being a continental tree, its success on the west coast of Britain is somewhat surprising, but it is there that it finds our climate at its moistest and mildest. Many fine specimen trees have attained heights up to 120 feet in the space of 90 years since the Big Tree was first introduced here. Its distinctive shape and habit of keeping its foliage low down when open-grown, make it a valuable ornamental tree in parklands. It is unlikely to be used for forest planting, as the Redwood has all its useful qualities, besides others of its own, such as fire resistance and the ability to reproduce itself from old stools.

The maximum heights and girths recorded for the Redwood in California are 340 feet and 78 feet respectively. The Big Tree is stouter but not so tall, scaling 320 feet high by 90 feet girth.

pictures for sequoia

sequoia sempervirens sequoia sempervirens. >>>>

sequoia gigantea sequoia gigantea. >>>>

sequoia gigantea sequoia gigantea. >>>>

cones and fruits cones and fruits. >>>>

branchlets branchlets. >>>>

park conifers park conifers. >>>>


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