The Principal Species of Wood: Their Characteristic Properties / First Edition

Locality.

Features of Tree.

Color, Appearance, or Grain of Wood.

Structural Qualities of Wood.

Representative Uses of Wood.

Weight of Seasoned Wood in Pounds per Cubic Foot.

Modulus of Elasticity.

Modulus of Rupture.

Remarks.

TEAK (Tectona.). GREENHEART (Nectandra.).

There are two Teaks; the principal one (Tectona grandis), a native of Asia, has been called the "Oak" of the Indian forests, the other (Oldfieldia africana) is an African tree.[60] The Greenheart (Nectandra rodiali) is of the laurel family and grows in South America. The woods, although foreign, are of such nature as to have widely established reputations, and each has at some time been used in construction.

Teak suggests oak, save that it is lighter and has a more uniform structure. It is very durable, and an oily secretion repels insects and preserves iron fastenings. During the supremacy of wooden vessels it was regarded as one of the best ship-building woods in existence. The grain fits it for carvings, and it is now known in North America chiefly because of this fact. Indian teak is the wood usually referred to.

Greenheart was early placed among the first class of ship-building woods by Lloyd's Register, and is yet taken to Europe to some extent for dock-and ship-building and for implements, but is seldom found and but little known in the United States. It is strong, hard, durable, and extremely heavy, the latter quality being so pronounced as to limit its field of usefulness. [p116]

Teak. Tectona grandis.

Greenheart. Nectandra rodiali.

MAHOGANY. (Swietenia, Khaya, Soymida, Cedrela, etc.)

There are three principal mahogany trees: the Central American or true mahogany (Swietenia mahogani), the African mahogany (Khaya senegalensis), and the Indian mahogany (Soymida febrifuga). There are also minor species called mahoganies.[61] American mahogany was originally divided by dealers into Spanish and Honduras wood, the former from the then Spanish-American possessions. A considerable supply now comes from Mexico, taking name from port of shipment; as, Frontera, Laguna, Santa Ana, Tecolutla, Minatitlan, and Tonala, desirability being much in the order named. The African field is the latest and probably most important, very large quantities of its wood being distributed through English markets.

Mahogany, placed among the second class of ship-building woods by Lloyd's Register, was once used to some extent in place of oak in naval architecture, but is now so greatly valued for decoration as to be employed for little else, save occasionally the hulls of small pleasure craft. The decorative value is due to a combination of beauty, working qualities, and durability. Beauty is influenced by both grain and warm red color. The latter is generally light, and although it subsequently darkens, in most cases, to a characteristic and rich reddish-brown, is usually induced immediately by stains. The grain is not only beautiful of itself, but is such as to receive those stains and finishing processes thus demanded. Different localities produce woods varying in tint and grain. Individual [p119] trees also differ in desirability. No two are alike. Beautiful grain effects are often obtained in "crotches" or junctions between trunk and branch, and such pieces bring high prices. Mahogany is generally used as a veneer. Layers are glued either to some central piece or "core" or else to one another. The layers are arranged so as to cross one another's grain, and results are usually thought to be more desirable than those obtained from solid wood. Few woods glue better, and few shrink or distort less when in place.

"Spanish Cedar" (Cedrela odorata) is a broadleaf wood, and not a conifer as is usually supposed. It is nearly related to, and usually found and cut with, true mahogany. Lindley[62] divides Cedrelecæ into two sub-orders: Swieteniæ, including the true mahoganies, and Cedrelæ, with nine genera and twenty-five species distributed over tropical Asia and America.

Prima vera or white mahogany belongs to Bignoniaceæ, which also includes the catalpas. [p120]

Mahogany. Swietenia mahogani Jacq.

White Mahogany. Prima vera. Tabeuia Donnell-Smithii (Rose).

Spanish Cedar, Mexican Cedar. Cedrela odorata Linn.

Representative Uses of Wood.

Weight of Seasoned Wood in Pounds per Cubic Foot.

Modulus of Elasticity.

Modulus of Rupture.

Remarks.

EUCALYPTUS. (Eucalyptus.)

These trees, locally known as Stringy-barks, Iron-barks, and Gum-trees, are natives of Australia and the neighboring islands. Some of the nearly four hundred species have been widely transplanted, although none have thus far succeeded in this country outside of Florida and California.[63] The Blue Gum (E. globulus) is the species commonly referred to when Eucalyptus is mentioned in North America.

The Eucalypts are noted for their great size, rapid growth, tough, durable wood, and alleged effect upon health. Size is illustrated by the species Eucalyptus amygdalina, specimens of which have reached a height of four hundred and eighty feet and are thus the tallest, although not the largest, trees known to man. Growth is shown by specimens of the Eucalyptus gunnii, which have grown in excess of two feet a month during the first year.[64] The working qualities of Jarrah, Karri, and Tuart woods (E. marginata, E. diversicolor, and E. gomphocephala) are such as to cause them to take high rank in local construction. The first two have been preferred beyond all other species for paving the streets of London and of Paris. Some improvement in health is said to have followed the introduction of the Blue Gum (Eucalyptus globulus) in malarial districts, such as those around Rome. It is not certain whether these results are due to the presence of essences in the foliage, although medicinal properties are ascribed to them and they are used in the preparation of listerine and similar compounds, or [p124] whether they are due to the fact that the leaves evaporate unusual quantities of water drawn by the roots from the soil.[65]

The trees are characterized by leathery evergreen foliage of many shades, such as blue, gray, and green. The leaves of young and old trees differ widely in some species. Those of young blue gums are bright blue, oval, and stalkless, while leaves of older trees have stems, are dark green and sickle-shaped. The characteristic odor is the only point in common between the foliage of the old and young of this species. There are, as stated, nearly four hundred species. [p125]

Jarrah. Eucalyptus marginata.

Modulus of Elasticity.

Modulus of Rupture.

Remarks.

Karri. Eucalyptus diversicolor.

Modulus of Elasticity.

Modulus of Rupture.

Remarks.

Tuart. Eucalyptus gomphocephala.

Modulus of Elasticity.

Modulus of Rupture.

Remarks.

Blue Gum, Fever Tree. Eucalyptus globulus.

Color, Appearance, or Grain of Wood.

Structural Qualities of Wood.

Representative Uses of Wood.

Weight of Seasoned Wood in Pounds per Cubic Foot.

Modulus of Elasticity.

Modulus of Rupture.

Remarks.

NEEDLELEAF WOODS.

The trees affording these woods cover large areas in the natural forests of the Northern Hemisphere. They exist, but to an unimportant extent, in the South. Cedar, larch, and cypress figure in ancient history, but woods generally were not employed until recent times.[71] Pine, spruce, hemlock, and other so-called soft woods are of this group.

Needle-leaved woods are characterized by uniform fibre-conditions, presence of resins, and lighter weights. The vertical structure consists of simple, similar, elongated tubes or cells, tapering and finally closing at their ends, known as tracheids. These are arranged with more or less regularity, and woods are correspondingly easy to work. Pith-rays are scarcely visible, and sections do not show pores. Cavities known as resin-ducts, and which are not real vessels but rather simple intercellular spaces, secrete resins so important in making these woods durable and elastic. Trees afford large, straight pieces. Woods are used in carpentry and heavy constructions. The total requirement greatly exceeds that for hard woods.

The resinous, usually evergreen, leaves and the cones are sufficient to identify these trees. Needleleaf, softwood, conifer, and evergreen trees are the same. [p130]

PINE. (Pinus.)

The pines have smooth, straight, solid trunks, usually destitute of branches for many feet from the ground. There are needle-shaped, more or less cylindrical, evergreen leaves from one to many inches in length, gathered in clusters of two, three, or five, their number and the fact that they are thus clustered being important bases of classification. There are also cones of woody overlapping scales. They reproduce with difficulty,[72] and mature so slowly that ultimate survival of modern conditions must probably be as cultivated trees.

Thirty-nine of the seventy known species of pine are found in the United States. These with their woods are separated into two groups known as hard and soft pines. The Dantzic or Northern pine (Pinus silvestris) is the principal European species. [p131]

SOFT PINE.

White pine (Pinus strobus) grows in the north, central, and eastern United States and was formerly the important tree of North America. It emphasized the forest industries of Maine and of Michigan, and methods connected with harvesting it have influenced logging practices in many fields. It was long the only softwood seriously considered by Northern lumbermen. Thirty per cent of the sawn timber and lumber used in this country in 1899 was drawn from this species.[73] White pine is diminishing so rapidly as to be already practically unobtainable in many places.

The Sugar Pine (Pinus lambertiana) of the Western States is a tree growing at high elevations and is so large as to take rank with the redwoods and other of the world's greatest trees. Some material is derived from the Western white pine (Pinus flexilis) and one or more minor species. Sugar pine resembles, but is not as desirable as, white pine. The sweetish exudations from this tree are sometimes used in medicine. [p132]

HARD PINE.

The longleaf pine (Pinus palustris) is distinctly the most important of its group. The wood is ideal for heavy constructions. Beams, docks, trestles, and frames of cars are formed of it. The trees afford the greater bulk of turpentine, tar, and resin, or "naval stores," produced in this country.[74] Cuban, shortleaf, and loblolly pine woods (P. heterophylla, P. echinata, and P. tæda) are nearly similar. Longleaf and Cuban pines are seldom separated, while shortleaf and loblolly pines are also mixed. Longleaf pine usually affords finer structure and more heartwood than Cuban pine. Strength and weight averages of both woods are in excess of those of shortleaf and loblolly pines. No method of invariably telling these four woods apart has as yet been determined. (Roth.) Any or all of them are practically liable to be delivered in response to a demand for Southern pine. Johnson considers shortleaf pine as good as longleaf pine of equal weight, and suggests environment as a means of identification.

Palustris, signifying "swampy," is misleading, since long leaf pine prefers dry, sandy soil and tracts known as "pine barrens." Mitis refers to the soft, delicate foliage of shortleaf pine. Tæda signifies "torch." The trees may be told by differences in their leaves and cones. [p133]

A confusion exists in the naming of the pines. American white pine is known as yellow or Weymouth pine in Europe, and all American hard pines are there often known as pitch pines. The European, Dantzic, or Northern pine has also many names, principally depending on port of shipment. Georgia, Southern, Yellow, Hard, and even Pitch pine, are interchangeable names in this country. The species palustris has thirty local names. [p134]