Timber
trees cut down, squared, or capable of being squared, into beams, rafters, boards, planks, etc., to be employed in the construction of houses, ships, etc., or in carpentry, joinery, etc.
Timber is usually sold by the load. A load of rough or unhewn timber is 40 cubic feet, and a load of squared timber 50 cubic feet, estimated to weigh 2,000 pounds. In the case of planks, deals, etc., the load consists of so many square feet. Thus, a load of one-inch plank is 600 square feet, a load of planks thicker than one inch equals 600 square feet divided by the thickness in inches. The term is often used for all kinds of felled and seasoned wood. It is also a general term for growing trees yielding wood suitable for constructive purposes. The chief are fir, pine, oak, ash, elm, beech, sycamore, walnut, chestnut, mahogany, teak, etc.
In the United States there are 300 species of trees, the smallest of which grows to a height of 30 feet. In South America the number is much greater, and India possesses about 900 species of timber trees. The species in England do not exceed 30, and in France or Germany there are only a few more. Yet, though the kinds of wood are so much more limited in European countries, there are almost as few in general use in the United States as in Europe. The smallness of the number of species of timber known to commerce is at first glance very remarkable, but it is accounted for in this way. The great great consumption of timber is for architectural and other constructive works which are usually carried out on a scale of some magnitude, and for such purposes large quantities of the kind or kinds chosen are required.
It is very desirable, therefore, that the TIMBER wood selected should be plentiful, durable, more or less easily worked, fairly uniform in quality, and moderate in price.
As yet the very useful timbers have been obtained from gregarious species of trees growing in the forests of the N. temperate regions of the globe, and the most important of these are a few kinds of fir and pine. From the tropics, where the social species are fewer, come the harder, heavier, and more richly colored or figured kinds, some of which are used in Europe and North America only for furniture and decorative purposes. Some of these tropical woods are, however, of extraordinary strength, and possess other valuable properties which will bring them sooner or later into use for building purposes. This is all the more certain to be the case as both in North America and in Europe the forest-covered land is being stripped of its best timber at a rapidly increasing rate. Trees are of such slow growth that it takes many years before they are large enough to yield useful timber; so that when the primitive forests of a country are once cut down the keeping up of a supply by planted trees is a very difficult matter.
Chief Commercial Timbers. - The following are the best known and most used timbers in Great Britain. Baltic redwood (Pinus sylvestris), perhaps the most generally useful of all, is employed for roofing and flooring, and often for all other internal and external wood work of better-class houses and other buildings. It is also used for paving streets and many other purposes. This wood in the cut state is called "yellow deal" in England.
American yellow pine (Pinus strobus), called white pine in its native country, is also very largely imported for the internal joiner work of buildings, parts of furniture, etc., but it is not suited for external work. Like the last, it is an excellent and easily worked timber. Baltic white wood (Abies excelsa) has for a considerable number of years taken the place of redwood for joists, flooring boards, roof timbers, etc. It is a distinctly inferior wood. American pitch pine (Pinus rigida), found over a large extent of country in the Eastern States, is an important timber. It has been much used in England for open roofs and for the whole of the wood-fittings of churches, halls, and the like. The annual rings of this wood are strongly marked, so that its planed surface looks striped. It is a heavy and highly resinous, but not very easily worked wood. The Douglas or Oregon pine (A. Douglasii or Pseudotsuga Douglasii) of northwestern America, between 200 and 300 feet in height, yields a timber of great length without knots, TIMBER suitable for masts, spars, and many other purposes.
Under the name of Californian redwood, the timber of Sequoia sempervirens has of late years been to some extent imported into Great Britain. Like the last, the tree is of great size, and the wood is easily got free of knots. It is of a pleasing red color (most of the socalled red pine woods are nearly white), and easily worked in the longitudinal direction, but difficult to cut clean across the grain. grain Another recently imported wood is the Kauri pine of New Zealand.
The Kauri (Dammara australis) is also a majestic tree, and the wood is highly prized for all general purposes in its native country. It seems to have some tendency to warp, but this may be owing to defective seasoning. We may mention among coniferous woods that of the deodar (Cedrus Deodara), which, though not used in Great Britain, is extremely durable, and of great importance in northern India.
Among the more important American coniferous timbers, some of which have been already referred to, are the white pine (Pinus strobus), called in England yellow pine; the yellow pine of the Eastern States (Pinus mitis); the hemlock; the black spruce; the Douglas pine; Californian redwood; the white cedar (Chamacyparis thyoides); the red cedar (Juniperus virginiana); as well as the larch or tamarack (Larix americana).
Of timbers from dicotyledonous or, as they are sometimes called, foliaceous trees oak is the most important. The oak timber grown in the N. of Europe is obtained from two or three varieties of one species of Quercus, or from distinct but closely allied species. The timber possesses in a high degree the useful properties of a hardwood. It is strong, tough, elastic, and not too heavy. Its sp. gr. averages about .800. Few woods are more durable or less affected in exposed situations by alternations of wet and dry weather. It is still used largely in shipbuilding and for many purposes in civil architecture, but for the latter it is much more expensive than pine wood.
Oak has the defect of rusting iron which pierces it or which is in contact with it. One or two American oaks also yield valuable timber. Teak, from an Indian tree, is next in importance to oak as a constructive timber. It has just the opposite effect on iron, as it protects the metal from rust, a property which gives it great value as a backing for the armor plating of ships. Teak is neither quite so hard nor so strong as oak, but it is as difficult to cut with tools, and it is rather lighter when thoroughly seasoned.
TIMBER Besides its extensive use in shipbuilding, it has been of late years used for external architectural work. Elm, though of much less consequence than oak as building timber, is nevertheless a good deal employed for engineering purposes; it is also used in shipbuilding for keels and other parts under water. Elm is only of great durability if kept either quite dry or constantly wet. For other timbers belonging to the same great class of trees, such as ash, beech, hornbeam, sycamore, lime, and birch, which have more restricted applications, see their respective heads. In the S. of Europe the timbers of the chestnut (Castanea vesca) and the walnut are extensively used.
There are a few exceptionally remarkable timbers which may just be named. Greenheart, which is of extraordinary strength, is believed to contain some principle which resists the attacks of boring worms when used for piles. Sabicu (Lysiloma sabicu), which is plentiful in Cuba, is another immensely strong wood. Both these timbers are heavier than water, and are used in shipbuilding. The Jarrah wood (Eucalyptus marginata) of Western Australia is believed to be extremely durable for sleepers and paving blocks.
Recently a few of the streets of London have been paved with it. Lignum vitæ (Guaiacum officinale) is of all woods the one which comes nearest to a strong metal in resistance to tear and wear.
Furniture and Ornamental Woods.- Mahogany is by far the most important of furniture woods, and it has many minor applications as well. Perhaps no other timber has such valuable properties for the construction of cabinets, sideboards, tables, or casing of any sort. For a hardwood it is easily worked; it is close-grained, takes a fine polish, and is very durable; if well seasoned it is not apt to warp, shrink, or crack, and its color improves with age. Some pieces of finely "curled" or figured mahogany bring a very high price. Oak, though also an excellent wood for furniture, is more difficult to season, more laborious to work, and less easy to obtain free of defects.
The black walnut (Juglans nigra) of Canada and the United States is much used for furniture. It is of a pleasing dark color, and comes nearer Spanish mahogany in suitability for cabinet work, but is not so hard. Italian or Circassian walnut (Juglans regia) is harder, and as a rule much more richly figured. It has been used for centuries for carving and furniture in Italy and other European countries. Much old walnut furniture is badly "worm eaten." Brazilian rosewood, the product of a much smaller tree TIMBER than any of the above, is a strong, hard, heavy material, but fairly easily worked.
It is of a dark, rich brown color, with beautiful streaks and cloud-like markings of a still darker tint, which more nearly resembles those of a colored marble than any other known wood. It has been long used in Europe for costly furniture. Satinwood, of which there are two kinds much the same in appearance, is something like rosewood in hardness and fineness of grain. Owing to their closeness of grain neither holds glue well.
Except that it is of a different and much lighter color, the figure of satinwood much resembles the "curl" of mahogany.
Ebony is another of the costly cabinet woods which is also hard and heavy. It is particularly close in the grain, so that it is suitable for drawing instruments as well as for cabinets, caskets, and the like. Ebony is black or nearly black in color, and has been prized for making furniture with ivory and other "inlays" from ancient Egyptian times. Beautiful work of this kind is still made in Paris.
The strikingly mottled Calamander wood of Ceylon and the fine marble wood of the Andaman Islands are both from ebenaceous trees. Among the very beautiful and for the most part costly woods used only for veneering and inlaying furniture and small ornamental articles are tulip wood (Physocalymma florida), snake or letter wood (Brosinum aubletii) purple heart (Copaifera Martii), and zebra wood (Connarus guianensis) from the tropical parts of America; to which may be added Amboyna wood from Singapore. Bird's-eye maple, a beautifully spotted or "eyed" light wood, is used in its native country (North America) for furniture, and was formerly much in favor for this purpose in England. In the S. of Europe the wood of the olive and of the orange are used for cabinet work. In Australia some species of acacia, such as black wood (A. melanoxylon) and myallwood (A. homalophylla), which are dark woods, the former, especially, often beautifully figured, are used for furniture; so also are several other woods, including forest oak (Casuarina torulosa), muskwood (Olearia argophylla), and cypress pine (Frenela robusta), Queensland tree. Of late years, under the name of African mahogany, the botanical source of which is still uncertain, a wood somewhat resembling ordinary mahogany has been imported in some quantity into England from the coast of Guinea, and seems to be coming into favor for some kinds of cabinet work.
Nature of Wood. - The stem or trunk of an ordinary exogenous tree consists of a central pith and rings or zones of TIMBER fibro-vascular bundles (composed of nuthis class the new wood forms next the bark, and is called sap-wood (alburnum). Gradual changes occur in these annual lary rays radiate. In a growing tree of this class the new wood forms next the rings or layers of new wood as they be- come older, and in time, which varies from one to many years, they get hard- Gradual changes occur in these annual rings or layers of new wood as they become older, and in time, which varies from one to many years, they get hardened or solidified into ripe wood or heart ber consists. These changes are of a chemical and physical character, and, al- though it is the hardening of the wood ber consists. These changes are of a chemical and physical character, and, alwood. of a growing tree with age that gives it its technical value, yet the change is, physiologically, an incipient process of degradation which ends in decomposition.
It is only in a few kinds of trees, however, that the decay of the wood is rapid. This duramen or heartwood, when properly treated after felling, is generally of a lasting nature, and in the hardwoods especially is usually of a darker color than the sapwood; but in some pine woods the sapwood, soon after the tree is cut down, gets darker than the heart wood, and is of a bluish or greenish color. The properties of wood depend partly on the mode of union of the fibers, and partly on the constituents, such as gum, resin, tannic acid, etc., which occur in the cellular and intercellular spaces. But there is also a small proportion of nitrogenous constituents which set up a kind of fermentation in damp wood, and especially in young spongy wood, exposed to the air, and are the cause of its decay.
In other circumstances, however, even in the presence of moisture, but where the access of oxygen is prevented, some kinds of wood will keep for an enormous length of time. Pieces of wood have been taken logical formations which are scarcely distinguishable from sound timber recently cut. The timber used in the construction of a house or other building should be thoroughly dried before being put in, and air allowed to circulate about it. This is especially necessary with regard to joists and flooring near the surface of the ground, otherwise damp and want of is especially necessary with regard to liable to be attacked by dry rot.
The apparent sp. gr. of wood varies from 0.383 (poplar wood) to 1.333 (lignum vitæ), and perhaps some kinds are even denser. But the sawdust of nearly all woods is heavier than water, and the actual specific gravity (i. e., of the wood apart from enclosed air) is much the same in all. The quality and the apparent specific gravity of timber from the same species of tree often widely vary. Soil, climate, whether they grow TIMBER is only two-thirds the price of that which determine to a large extent the value of wood from trees of a like kind. For example, the timber of the Scotch fir comes from Danzig, while the wood of (Pinus sylvestris) brought from the Baltic varies so much that the Swedish wood is only two-thirds the price of that which the same tree grown in Scotland is of less value than either. With mahogany the qualities differ far more. or Cuban mahogany is of much greater value than, and sometimes twice as heavy as, Honduras or Bay mahogany from the same species of tree. Each of these vacontain the least amount of natural sap. They should not be allowed to remain in quality in different samples of the wood.
Spanish Seasoning of Timber. -Trees, and especially deciduous trees, should always long on the ground where they are cut contain the least amount of natural sap.
They should not be allowed to remain long on the ground where they are cut cut up into planks or boards, these are ought to be stacked with packing pieces between them, to allow the sap freely to evaporate. They should also be covered six months completely protected from cut up into planks or boards, these are usually in the first place laid horizontally, rain. Afterward they are placed for the same length of time in a vertical position allowed to remain in this position for six months completely protected from rain. Afterward they are placed for the same length of time in a vertical position on racks and kept a little apart. Most ordinary woods require this length of time to season them properly in a natural way, though some are ready for use: thin cut wood, by placing it in hot air timber can be hastened by steaming or boiling it, or, in the case of planks and thin cut wood, by placing it in hot air chambers. Natural seasoning is, however, by far the best. For cabinet work and the better kinds of joinery the natur- ally seasoned wood is, just before being used, usually put for a week or 10 days in a stove heated to about 120° F. The thorough seasoning of wood is of great importance, but too frequently is only partially effe effected. partially effected. ternal woodwork of buildings oil paint is usually employed, and the painting should be renewed every four or five years.
Wooden ships and boats are is usually employed, and the painting years. with bichloride coated with tar or pitch. But for such purposes as pavement, sleepers, piles, etc., treatment with certain chemicals which penetrate the wood more deeply has been proposed. Three methods of doing this have been chiefly tried, and of these the impregnation wit of mercury is called kyanising; when 16 TIMBER sulphate of zinc is used the process is termed burnettising; and the third method-the only one extensively practiced in Great Britain-is creosoting. The latter consists in steeping the wood in creosote oil, from 8 to 12 pounds being required for every cubic foot of timber.
Since 1882 a new process introduced by H. Aitken, of Falkirk, has been under trial-namely, the soaking of timber, according to its bulk, from 2 to 12 hours in melted naphthaline. This is a volatile substance, which must so far be against its efficiency, but the results of the experiments are said to give good promise of success.