Encyclopædia Britannica, Ninth Edition/Teak
TEAK[1] may justly be called 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 of 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 younger Linnæus called it Tectona grandis. It is a large deciduous tree, of the natural order Verbenaceæ, with a tall straight stem, a spreading crown, the branchlets four-sided, with large quadrangular pith. It is a native of the two Indian peninsulas, and is also found in the Philippine Islands, Java, and other islands of the Malay Archipelago.
Teak (Tectona grandis).
In India proper its northern limit is 24° 40' on the west side of the Aravalli Hills, and in the centre near Jhansi, in 25° 30' lat. In Burmah it extends to the Mogoung district, in lat. 25° 10'. 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 32d.
Teak requires a tropical climate, and the most important forests are found in the moister districts of India, where during the summer months heavy rains are brought by the south-west monsoon, the winter months being rainless. In the interior of the Indian peninsula, where the mean annual rainfall is less than 30 inches, no teak is found, and it thrives best with a mean annual fall of more than 50 inches. The mean annual temperature which suits it best lies between 75° and 81° Fahr. Near the coast the tree is absent, and the most valuable forests are on low hills up to 3000 feet. 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 often 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, are from 1 to 2 feet in length and from 6 to 12 inches in breadth. On coppice shoots the leaves are much larger, and not rarely from 2 to 3 feet 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 January and February. On. the east side of the Indian peninsula, the teak flowers during the rains in October and November. In Java the forests 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 all other trees. The small oily seeds are enclosed in a hard bony 1-4 celled nut, which is surrounded by a thick covering, consisting of a dense felt of matted hairs. The fruit is enclosed by 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 come up at all.
The bark of the stem is about half an inch thick, grey or brownish grey, the sap wood 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 of each 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 Burmah 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. [4] Being one of the few Indian timbers which are really durable, 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 extensively used for the last-named purpose, it was supposed that the demand for teak would decrease. This, however, has not been the case, for the wood is still very largely used for the backing of iron-clads and for decks of large vessels. 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 sapwood, but rarely attack the heartwood of teak. It is not, however, 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 those 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 Ib per cubic foot. [5] Its weight, therefore, is a little less than that of English oak. Green teak timber, however, is heavier than water, and unless thoroughly seasoned it cannot be floated. In Burmah, therefore, where the rivers are used to float the timber to the sea-ports, a peculiar mode 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 sapwood, 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 Burmah. [6] For a long time to come, the rivers of Burmah and Siam will continue to afford the most convenient and most economical routes for the transport of timber. 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 Maulmain.
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 Burmah oil is extracted from the timber on a small scale, 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, Burmah, 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 the timber 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 Burmah 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 soil are 5 to 10 feet high, and instances of more rapid growth are not uncommon. In the plantations which have been made since 1856 in Burmah, the teak has on good soil attained an average height of 60 feet in 16 years, with a girth, breast high, of 19 inches. This is between 16° and 18° N. lat., with a mean annual temperature of 78° F. and a rainfall of 100 inches. In the Burmah plantations it is estimated that the tree will, under favourable circumstances, attain a diameter of 24 inches (girth 72 inches) at the age of 80. Timber of that size is marketable, but the timber of the natural forests which is at present brought to market in Burmah has grown much more slowly, the chief reason being the annual forest fires, which harden and impoverish the soil. In the natural forests of Burmah and India teak timber with a diameter of 24 inches 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 grow much faster; 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 100 to 150 feet high, even under the most favourable circumstances, and stems more than 100 feet 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. The stems had 106 to 114 feet to the first branch, with a girth, at 6 feet off the ground, from 7 to 16 feet. Larger girths, up to 25 feet, are not uncommon.
The teak tree does not usually form pure forests. It is associated with bamboos and 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 Burmah, the object has been to raise forests of teak mixed with bamboos and other trees.
Most of the teak timber produced is consumed in India. The produce of the magnificent 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 large quantities are imported from Burmah 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 Burmah, principally from Rangoon and Maulmain. Of the other teak-producing countries, Java exports a little; there have also been exports from Saigon; and since 1882 Bankok has sent considerable quantities to Europe. But the Burmah coast is the chief source of supply at present. Rangoon has for a very long time been an important place for shipbuilding, teak being the chief timber used; between 1786 and 1825 111 European vessels were built at Rangoon, aggregating 85,000 tons. At the same time timber was exported, and, when the place was taken by the British in 1852, teak was the chief article of export. Maulmain 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 16,680 tons, and estimated to have required for their construction 24,000 loads of teak timber. The forests from which Maulmain 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 Burmah ports was slow at first, but has gone on rapidly since Rangoon became a British port. Since that time the timber brought to the Burmah ports has come from the following sources:—(1) from the forests in the British coast provinces, Pegu and Tenasserim; (2) from the forests in the former kingdom of Burmah, floated to Rangoon down the Sitang and Irrawaddy rivers; (3) from the forests in the Shan states formerly tributary to Burmah, from the Karenni country, and from Siam, which is all floated to Maulmain by the Salwin river. Since 1856 the increase of the supply derived from these three sources has been large, as will be apparent from the following averages for the eight years 1856-57 to 1863-64 and for the two years 1883–84 and 1884–85:—
| x | 1856-7 to 1863-4. | 1883-4, 1884-5. |
| Loads. | Loads. | |
| From the British coast provinces, Pegu and Tenasserim. | 22,675 | 44,228 |
| From Burmah by Sitang and Irrawaddy rivers | 6,890 | 66,663 |
| From Shan states, Karenni, and Siam, by Salwin river | 55,491 | 163,751 |
| Total supplies | 85,056 | 274,642 |
| Exports by sea | 76,763 | 153,192 |
| Local consumption in Rangoon and Maulmain | 8,293 | 121,450 |
Of the quantities exported, between 38,000 and 65,000 loads[7] have gone beyond India during this period, the balance having been sent to Calcutta, Bombay, and other Indian ports. The quantities here stated do not include the timber consumed in Upper Burmah, nor that brought from the forests drained by the Menam and Mekhong rivers on the east side of the Indo-Chinese Peninsula, nor the teak produced in Java and the other islands of the Malay Archipelago, and in the extensive forests of the western peninsula of India. No data are yet available for a precise estimate; but the total amount yielded by these forests, and consumed locally or exported, appears to be not less than 500,000 loads or tons a year.
In British India a large portion of the teak-producing tracts have since 1856 been placed under conservancy management, and similar measures will doubtless be extended to the forests in Upper Burmah, now annexed to the British empire, as well as to the forests of the feudatory native states. In British India, the area of state forests demarcated in order to be permanently conserved[8] was in 1885 (in round figures) 33,000 square miles, and the teak-producing tracts included in this area may be estimated to cover about 12,000 square miles, or 7,680,000 acres. Large additions will be made to this area, especially in Upper Burmah. Of teak plantations, 12,000 acres have been formed in Burmah, 563 acres in Coorg, 3436 at Nilambur in Malabar, and about 2000 acres in other districts. There are good grounds for estimating the future yield of plantations at the rate of 50 cubic feet (one ton) per acre annually. The natural forests will, in their present impoverished condition, not furnish more than one cubic foot per acre annually, but, as protection against fire is gradually extending, the proportion of teak is everywhere being increased by cultural operations in the forests, and the effect of these measures will eventually manifest itself by a considerable increase in the yield. In their present condition, the natural forests demarcated in India up to 1887 may be expected to yield 150,000 tons a year, while the produce of the plantations will eventually add 18,000 tons more. The teak forests in Java were surveyed in 1871, and their area was found to be 2280 square miles, while the plantations in that island in 1880 amounted to 24,710 acres. These figures will serve to show that, if the system commenced in India and Java is maintained, there is no reason to apprehend a diminution of the teak supply. (D. BR.)
- ↑ 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.
- ↑ The rate in the London market since 1860 has fluctuated between £10 and £15 per load of 50 cubic feet.
- ↑ Hortus Malabaricus, vol. iv. tab. 27, 1683.
- ↑ 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 112 inches 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, vol. vii. p. 260). In the wall of a palace of the Persian kings near Baghdad, which was pillaged in the 7th century, two Americans found in 1811 pieces of Indian teak which were perfectly sound (Ouseley, Travels in Various Countries of the East, vol. ii. p. 280, note 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.
- ↑ At 44·8 lb per cubic foot a load of 50 cubic feet weighs a ton (2240 lb), hence in the Burmah ports a ton of teak timber is taken as equivalent to a load of 50 cubic feet.
- ↑ It has been erroneously stated that the tree in Burmah is tapped for its oil before felling.
- ↑ Of the teak exported to foreign conntries from India in 1883-84, 27,356 tons went to Great Britain, 8594 tons to Egypt, 2056 tons to Ceylon, 1984 tons to Japan, and 1823 tons to the Cape of Good Hope. The total quantity exported was 46,471 tons.
- ↑ Not including 16,000 square miles of second class reserves in the Central Provinces.