Online Encyclopedia

TEAK

Online Encyclopedia
Originally appearing in Volume V26, Page 486 of the 1911 Encyclopedia Britannica.
Spread the word: del.icio.us del.icio.us it!
TEAK,' the most valuable of all known timbers. For use in tropical countries it has no equal, and for certain purposes it is preferable to other woods in temperate climates also. Its price is higher than that cf any other timber, except mahogany.2 Great efforts have been made to find substitutes, but no timber has been brought to market in sufficient quantities combining the many valuable qualities which teak possesses. The first good figure and description of the tree was given by Rheede,3 the best modern picture being that given by Brandis.4 The younger Linnaeus called it Tectona grandis. It is a large deciduous tree, of the natural order Verbenaceae, with a tall, straight but often buttressed stem, a spreading crown, and the branchiets four-sided with large quadrangular pith. It is a native of the Indian peninsula, Burma and Siam, and is also found in the Philippine Islands, in Java and else-where in the Malay Archipelago. In India proper its northern limit is 24° 40' on the west side of the Aravaili Hills, and in. the centre, near Jhansi, in 25° 30' N. lat. In Burma it extends ' The Sanskrit name of teak is saka, and it is certain that in India teak has been known and used largely for considerably more than 2000 years. In Persia teak was used nearly 2000 years ago, and the town of Siraf on the Persian Gulf was entirely built of it. Saj is the name in Arabic and Persian; and in Hindi, Mahratti and the other modern languages derived from Sanskrit the tree is called sag, sagwan. In the Dravidian languages the name is teka, and the Portuguese, adopting this, called it teke, teca, whence the English name. 2 The rate in the London market since 186o has fluctuated between £10 and £2o per load of 5o cub. ft. 4 Hortus Malabaricus, vol. iv. tab. 27, 1683. 4 Forest Flora of North-West and Central India, Ill. t. 44. to near Myitkyina, in lat. 25° 30'. In Bengal or Assam it is not indigenous, but plantations have been formed in Assam as far as the 27th parallel. In the Punjab it is grown in gardens to the 32nd. Teak requires a dry tropical climate, and the most important forests are found in those districts of India where, during the summer months, heavy rains are brought by the south-west monsoon, the winter months being nearly rainless. In the interior of the Indian peninsula, where the mean annual rain-fall is less than 30 in., teak is more scarce, and it thrives best with a mean annual fall of more than 50 in. The mean annual temperature which suits it best lies between 750 and 81° Fahr. Near the coast the tree is absent, and inland the most valuable forests are on low hills up to 3000 ft. It grows on a great variety of soils, but there is one indispensable condition—perfect drainage or a dry subsoil. On level ground, with deep alluvial soil, teak does not always form regularly shaped stems, probably because the subsoil drainage is imperfect. During the dry season the tree is leafless; in hot localities the leaves fall in January, but in moist places the tree remains green till March. At the end of the dry season, when the first monsoon rains fall, the fresh foliage comes out. The leaves, which stand opposite, or only whorled in very young specimens, are from r to 2 ft. in length and from 6 to 12 in. in breadth. On coppice shoots the leaves are much larger, and not rarely from 2 to 3 ft. long. In shape they somewhat resemble those of the tobacco plant, but their substance is hard and the surface rough. The small white flowers are very numerous, on large erect cross-branched panicles, which terminate the branches. They appear during the rains, generally in July and August, and the seed ripens in the succeeding January and February. On the east side of the Indian peninsula, the teak flowers during the rains in October and November. In Java the plantations are leafless in September, while during March and April, after the rains have commenced, they are clothed with foliage and the flowers open. During the rainy season the tree is readily recognized at a considerable distance by the whitish flower panicles, which overtop the green foliage, and during the dry season the feathery seed-bearing panicles distinguish it from its associates. The small oily seeds are enclosed in a hard, bony, r–4-celled nut, which is surrounded by a thick covering, consisting of a dense felt of matted hairs. The fruit thus formed is further enclosed in the enlarged membranous calyx, in appearance like an irregularly plaited or crumpled bladder. The tree seeds freely every year, but its spread by means of self-sown seed is impeded by the forest fires of the dry season, which in India generally occur in March and April, after the seeds have ripened and have partly fallen. Of the seeds which escape, numbers are washed down the hills by the first heavy rains of the monsoon. These collect in the valleys, and it is here that groups of seedlings and young trees are frequently found. A portion of the seed remains on the tree; this falls gradually after the rains have commenced, and thus escapes the fires of the hot season. The germination of the seed is slow and uncertain; a large amount of moisture is needed to saturate the spongy covering; many seeds do not germinate until the second or third year, and many do not germinate at all. Where the teak tree is associated with dense clumps of bamboo, natural reproduction is almost absent, except when the bamboo flowers and dies, and even then, if the dry bamboos and the resultant bamboo seedlings are not burnt, such young teak as may germinate are likely to be smothered at once. The bark of the stem is about half an inch thick, grey or brownish grey, the sapwood white; the heartwood of the green tree has a -pleasant and strong aromatic fragrance and a beautiful golden-yellow colour, which on seasoning soon darkens into brown, mottled with darker streaks. The timber retains its aromatic fragrance to a great age. On a transverse section the wood is marked by large pores, which are more numerous and larger in the spring wood, or the inner belt of each annual ring, while they are less numerous and smaller in the autumn wood or outer belt. In this manner the growth ofeach successive year is marked in the wood, and the age of a tree may be determined by counting the annual rings. The principal value of teak timber for use in warm countries is its extraordinary durability. In India and in Burma beams of the wood in good preservation are often found in buildings several centuries old, and instances are known of teak beams having lasted more than a thousand years.' Being one of the most durable of Indian timbers, teak has always been used for buildings, particularly for temples, and in India it has been the chief timber employed for shipbuilding. When iron commenced to be exte.:sively used for the last-named purpose, it was supposed that the demand for teak would decrease. This, however, was not the case, for the wood was for long very largely used in shipbuilding. and though its employment in war-vessels has diminished, it is still in very great demand for " liners " and similar ships. It is also used for furniture, for door and window frames, for the construction of railway carriages, and for many other purposes. White ants eat the sap-wood, but rarely attack the heartwood of teak. It is not, however, Teak (Tectona grandis). proof against the borings of the teredo, from whose attacks the teak piles of the wharves in the Rangoon river have to be protected by a sheathing of metal. Once seasoned, teak timber does not split, crack, shrink, or alter its shape. In these qualities it is superior to most timbers. In contact with iron, neither the iron nor the teak suffers, and in this respect it is far superior to oak. It is not very hard, is easily worked, and takes a beautiful polish. It has great elasticity and strength, and is not very heavy. The average weight of perfectly seasoned wood fluctuates between 38 and 46 lb per cub. ft .2 Its weight, therefore, is a little less than that of English oak. Green teak timber, however, is heavier than water, so that, ' In one of the oldest buildings among the ruins of the old city of Vijayanagar, on the banks of the Tungabhadra in southern India, the superstructure is supported by planks of teakwood r z in. thick. These planks were examined in 1881; they were in a good state of preservation and showed the peculiar structure of teak timber in a very marked manner. They had been in the building for 500 years (Indian Forester, vii. 26o). In the wall of a palace of the Persian kings near Bagdad, which was pillaged in the 7th century, two Americans found in 18i1 pieces of Indian teak which were perfectly sound (Ouseley, Travels in Various Countries of the East, ii. 28o, n. 67). In the old cave temples of Salsette and elsewhere in western India pieces of teak have been found in good preservation which must have been more than 2000 years old. 2 At 44.8 lb per cub. ft. a load of 50 cub. ft. weighs a ton (2240 lb), hence in the Burma ports a ton of teak timber is taken as equivalent to a load of 50 cub. ft. unless thoroughly seasoned, the wood cannot be floated. In Burma, therefore, where the rivers are used to float the timber to the sea-ports, the method of seasoning teak by girdling has been practised from time immemorial. Girdling consists in making a deep circular cut through bark and sap into the heartwood, so as completely to sever communication between bark and sapwood above and below the cut. In teak, as in oak and other trees with well-marked heartwood, the circulation of the sap only takes place in the sap-wood, and the girdled tree therefore dies after a few days if the operation has been effectually performed. But if even the smallest band of sapwood is left connecting the outer layers of wood above and below the girdle, the tree is not killed, and often recovers completely. The girdled tree is allowed to stand one or two years, and longer if a very large-sized tree. Being exposed to the wind and to the action of the sun, the timber of a girdled tree seasons more rapidly and more completely than that of a tree felled green. The teak produced in the presidencies of Madras and Bombay and in the Central Provinces is as a rule felled green, and even when dry it generally is a little heavier than the timber from Burma.' For a long time to come, the rivers of Burma and Siam will continue to afford the most convenient and most economical routes for the extraction of teak timber from those countries. Indeed, the forests drained by the Salwin and its feeders are not likely ever to be worked otherwise than on the present plan, under which the logs are floated singly over the rapids and are caught and rafted lower down, at the kyodan or rope station, 70 miles above Moulmein. As already mentioned, teakwood contains an aromatic oil, which gives it a peculiarly pleasant smell and an oily surface when fresh cut. To this oil may probably with justice be ascribed its great durability. In Burma the oil is extracted from the timber on a small scale, to be used for medicinal purposes, by filling an earthen pot, which is placed inverted upon another, with chips of wood, and putting fire round it, upon which the oil runs down into the lower vessel. According to the colour and texture of the wood, several varieties of teak are distinguished in India, Burma and Java; in the timber trade, however, these distinctions are of no importance. Teak, as well as other trees, when standing isolated, forms side branches far down the stem, and the wood of such trees is more knotty and wavy, and generally heavier and darker-coloured than that of trees which have grown close together in a dense forest. Apart from the manner in which the tree had grown up in the forest, soil, elevation and climate have a great influence upon the grain and the mechanical qualities of teak as of other timbers. Most of the larger logs brought to market have an irregular crack or hollow in the centre, which commences at the butt and often runs up a long way. There is little doubt that this is generally due to the action of the fires, which scorch and often destroy the bark of young trees. Such external injuries are apt to induce decay in the wood. Moreover, most teak seedlings which come up naturally are cut down to the ground by the fires of the hot season; some are killed, but many sprout again during the rains, and this is generally repeated year after year, until a sapling is produced strong enough to outlive the fire. Such saplings have a very large pith, which dries up, causing a hollow in the heart; or a piece of the old shoot killed by the fire is enclosed by the new wood, and this also is apt to give rise to a hollow. The leaves of the teak tree contain a red dye, which in Malabar was formerly used to dye silk and cotton. Natives of Burma use the leaves as plates, to wrap up parcels, and for thatching. In its youth the tree grows with extreme rapidity. Two-year-old seedlings on good sod are 5 to 10 ft. high, and instances of more rapid growth are not uncommon. In the plantations which have been made since 1856 in Burma, the teak has on good soil attained an average height of 6o ft. in 15 years, with a girth, breast high, of 19 in. This is between 16° and 18° N. lat., with a mean annual temperature of 78° F. and a rainfall of loo in. In the Burma plantations it is estimated that the tree will, under favourable circumstances, attain a diameter of 24 in. (girth 72 in.) at the age of 80. Timber of that size is market-able, but the timber of the natural forests which is at present brought to market in Burma has grown much more slowly, the chief reason being the annual forest fires, which harden and impoverish the soil. In the natural forests of Burma and India teak timber with a diameter of "24 in. is never less than 100 and often more than 200 years old. In future, the timber grown in plantations and in forests under regular management may be expected to be much faster grown; and there is no ground for anticipating that rapidly grown timber will be less valuable than that of slow growth, which is at present brought to market. Like the other trees of the dry deciduous forest, teak does not attain any extraordinary size. The trees are not generally more than 10o to 150 ft. high, even under the most favourable circumstances, and stems more than too ft. to the first branch are not often found. Exceptionally tall trees were measured in 1861 in the Gwaythay forest in Pegu, east of the Sitang river, on gneiss. i It has been erroneously stated that the tree in Burma is tapped for its oil before felling- The stems had 106 to 114 ft. to the first branch, with a girth, at 6 ft. off the ground, from 7 to 16 ft. Larger girths, up to 25 ft., are not uncommon. The teak tree does not usually form pure forests. It is associated with bamboos and with a great variety of other trees, which have little market value, and, as a rule, thrives best in such company. Hence in the plantations established in Burma the object has been to raise forests of teak mixed with bamboos and other trees. Most of the teak timber produced in India is used in the country. The produce of the forests of Travancore, Cochin, the Madras presidency, Coorg, Mysore, Bombay, Berar and the Central Provinces is all so consumed. Formerly there was a considerable export from the ports of the western coast—Malabar, Kanara, Surat and Broach—but the country at present requires all the teak which its forests can produce; indeed the demand is in excess of the supply, and considerable quantities are imported from Burma to Calcutta, Madras, Bombay and other Indian ports. Small quantities are still exported from the ports of the western coast to Arabia and the coast of Africa. The chief export is from Burma, principally from Rangoon and Moulmein. Of the other teak-producing countries, Java exports a little; there have also been exports from Saigon; and since 1882 Bangkok has sent considerable quantities to Europe. But the Burma coast is the chief source of supply at present. Rangoon was for a long time an important place for shipbuilding, teak being the chief timber used: between 1786 and 1825 III European vessels were built at Rangoon, aggregating 35,00o tons. At the same time timber was exported, and, when the country was taken by the British in 1852, teak was the chief article of export. Moulmein became British territory at the close of the first Burmese war in 1826. At that time the place was a large fishing village, and it was mainly through the export of teak timber and the shipbuilding trade that it attained its present importance. From 1829 to 1841 upwards of 50,000 loads of teak timber were exported, and, in addition, 68 vessels were built during that period, aggregating 15,680 tons, and estimated to have required for their construction 24,000 loads of teak timber. The forests from which Moulmein first derived its supplies are situated on the Attaran river, a feeder of the Salwin. In 1836, however, timber began to come down from more distant forests, and in 1841 one-fourth only of the supply was brought from the Attaran forests. The increase in the export of timber from the Burma ports was slow at first, but has gone on rapidly since Rangoon became a British port. Since that time the timber brought to the Burma ports has come from the following sources:—(I) from the forests in the British coast provinces, Pegu and Tenasserim; (2) from the forests in the former kingdom of Burma, floated to Rangoon down the Sitang and Irrawaddy rivers; (3) from the forests in the Shan states formerly tributary to Burma, from the Karenni country, and from western Siam, whence it is floated to Moulmein by the Salwin river. The following table shows the figures of the imports and exports of British India for the years 1901–2 to 1905–6: Imports. Exports. Cub. Tons. Value Rs. Cub. Tons. Value Rs. 1901—2.... 17,842 13,03,968 60,671 71,53,855 1902–3 .... 32,081 24,96,317 57,500 68,67,8.79 1903–4.... 34,588 30,55,695 73,913 91,45,605 1904–5.... 46,915 42,46,190 46,912 60,05,383 1905–6.... 71,676 62,17,331 52,768 70,41,660 1906–7.... 61,696 60,71,557 44,202 61,48,291 Average.. 44,133 38,98,483 55,994 70,60,445 _ £259,899 = £470,696 Nearly the whole of the imports came from Siam, and of the ex-ports four-fifths were from Burma. The balance of the imports consisted of timber from Java, that of the exports of supplies sent from peninsular ports. 'Two-thirds of .the exports went to the United Kingdom, the other chief markets being ordinarily Germany, Ceylon and Australia. The recent great increase in the general teakwood trade is evidenced by the fact that the imports increased in six years from 17,842 tons to 61,696 tons. But it is noticeable that, whereas in 1901–2 the timber exported very largely exceeded the imports, in 1905–6 and 1906–7 the imports were larger than the exports, evidence of the great increase in Indian demand for teak timber; and, in all probability, of the steady regular outturn of the Indian forests, in comparison with increased imports from Siam, where the forests are not, like those in Burma, under regular working plan, designed to give a permanent annual yield and avoid any danger of exhaustion of the forests. In British India, including Burma, a large portion of the teak-producing tracts have since 1856 been placed under conservancy management with the object of preventing overcutting and maintaining a permanent and gradually increasing supply. This is the object of the working plans referred to The area of teak forest available in India and Burma is considerable, and every endeavour is made to conserve it and increase its production. Similar measures have been taken in Siam under the advice of officers borrowed from British India; and in the teak-producing native states in the peninsula the necessity for careful management is now well under-stood. The teak plantations in Java had come into bearing by 1908 and it was expected that the teak areas in the Philippine Islands would be similarly developed. (D. BR.; J. S. GA.)
End of Article: TEAK
[back]
EDWARD TEACH [THATCH OR THACH] (d. 1718)
[next]
TEAL (O.E. tele)

Additional information and Comments

There are no comments yet for this article.
» Add information or comments to this article.
Please link directly to this article:
Highlight the code below, right click and select "copy." Paste it into a website, email, or other HTML document.