SEASONING OF WOOD

A TREATISE ON THE NATURAL AND ARTIFICIAL PROCESSES EMPLOYED IN THE PREPARATION OF LUMBER FOR MANUFACTURE, WITH DETAILED EXPLANATIONS OF ITS USES, CHARACTERISTICS AND PROPERTIES

ILLUSTRATIONS

BY
JOSEPH B. WAGNER
AUTHOR OF "COOPERAGE"

NEW YORK
D. VAN NOSTRAND COMPANY
25 PARK PLACE
1917

COPYRIGHT, 1917, BY
D. VAN NOSTRAND COMPANY
THE·PLIMPTON·PRESS
NORWOOD·MASS·U·S·A

PREFACE

The seasoning and kiln-drying of wood is such an important process in the manufacture of woods that a need for fuller information regarding it, based upon scientific study of the behavior of various species at different mechanical temperatures, and under different drying processes is keenly felt. Everyone connected with the woodworking industry, or its use in manufactured products, is well aware of the difficulties encountered in properly seasoning or removing the moisture content without injury to the timber, and of its susceptibility to atmospheric conditions after it has been thoroughly seasoned. There is perhaps no material or substance that gives up its moisture with more resistance than wood does. It vigorously defies the efforts of human ingenuity to take away from it, without injury or destruction, that with which nature has so generously supplied it.

In the past but little has been known of this matter further than the fact that wood contained moisture which had to be removed before the wood could be made use of for commercial purposes. Within recent years, however, considerable interest has been awakened among wood-users in the operation of kiln-drying. The losses occasioned in air-drying and improper kiln-drying, and the necessity for getting the material dry as quickly as possible after it has come from the saw, in order to prepare it for manufacturing purposes, are bringing about a realization of the importance of a technical knowledge of the subject.

Since this particular subject has never before been represented by any technical work, and appears to have been neglected, it is hoped that the trade will appreciate the endeavor in bringing this book before them, as well as the difficulties encountered in compiling it, as it is the first of its kind in existence. The author trusts that his efforts will present some information that may be applied with advantage, or serve at least as a matter of consideration or investigation.

In every case the aim has been to give the facts, and wherever a machine or appliance has been illustrated or commented upon, or the name of the maker has been mentioned, it has not been with the intention either of recommending or disparaging his or their work, but has been made use of merely to illustrate the text.

The preparation of the following pages has been a work of pleasure to the author. If they prove beneficial and of service to his fellow-workmen he will have been amply repaid.

THE AUTHOR.

September, 1917

CONTENTS

LIST OF ILLUSTRATIONS

SEASONING OF WOOD

SECTION I

TIMBER

Characteristics and Properties

Timber was probably one of the earliest, if not the earliest, of materials used by man for constructional purposes. With it he built for himself a shelter from the elements; it provided him with fuel and oft-times food, and the tree cut down and let across a stream formed the first bridge. From it, too, he made his "dug-out" to travel along and across the rivers of the district in which he dwelt; so on down through the ages, for shipbuilding and constructive purposes, timber has continued to our own time to be one of the most largely used of nature's products.

Although wood has been in use so long and so universally, there still exists a remarkable lack of knowledge regarding its nature, not only among ordinary workmen, but among those who might be expected to know its properties. Consequently it is often used in a faulty and wasteful manner. Experience has been almost the only teacher, and theories—sometimes right, sometimes wrong—rather than well substantiated facts, lead the workman.

One reason for this imperfect knowledge lies in the fact that wood is not a homogeneous material, but a complicated structure, and so variable, that one piece will behave very differently from another, although cut from the same tree. Not only does the wood of one species differ from that of another, but the butt cut differs from that of the top log, the heartwood from the sapwood; the wood of quickly-grown sapling of the abandoned field, from that of the slowly-grown, old monarch of the forest. Even the manner in which the tree was cut and kept influences its behavior and quality. It is therefore extremely difficult to study the material for the purpose of establishing general laws.

The experienced woodsman will look for straight-grained, long-fibred woods, with the absence of disturbing resinous and coloring matter, knots, etc., and will quickly distinguish the more porous red or black oaks from the less porous white species, Quercus alba. That the inspection should have regard to defects and unhealthy conditions (often indicated by color) goes without saying, and such inspection is usually practised. That knots, even the smallest, are defects, which for some uses condemn the material entirely, need hardly be mentioned. But that "season-checks," even those that have closed by subsequent shrinkage, remain elements of weakness is not so readily appreciated; yet there cannot be any doubt of this, since these, the intimate connections of the wood fibres, when once interrupted are never reestablished.

Careful woods-foremen and manufacturers, therefore, are concerned as to the manner in which their timber is treated after the felling, for, according to the more or less careful seasoning of it, the season checks—not altogether avoidable—are more or less abundant.

There is no country where wood is more lavishly used or criminally neglected than in the United States, and none in which nature has more bountifully provided for all reasonable requirements.

In the absence of proper efforts to secure reproduction, the most valuable kinds are rapidly being decimated, and the necessity of a more rational and careful use of what remains is clearly apparent. By greater care in selection, however, not only will the duration of the supply be extended, but more satisfactory results will accrue from its practice.

There are few more extensive and wide-reaching subjects on which to treat than timber, which in this book refers to dead timber—the timber of commerce—as distinct from the living tree. Such a great number of different kinds of wood are now being brought from various parts of the world, so many new kinds are continually being added, and the subject is more difficult to explain because timber of practically the same character which comes from different localities goes under different names, that if one were always to adhere to the botanical name there would be less confusion, although even botanists differ in some cases as to names. Except in the cases of the older and better known timbers, one rarely takes up two books dealing with timber and finds the botanical names the same; moreover, trees of the same species may produce a much poorer quality of timber when obtained from different localities in the same country, so that botanical knowledge will not always allow us to dispense with other tests.

The structure of wood affords the only reliable means of distinguishing the different kinds. Color, weight, smell, and other appearances, which are often direct or indirect results of structure, may be helpful in this distinction, but cannot be relied upon entirely. Furthermore, structure underlies nearly all the technical properties of this important product, and furnishes an explanation why one piece differs in these properties from another. Structure explains why oak is heavier, stronger, and tougher than pine; why it is harder to saw and plane, and why it is so much more difficult to season without injury. From its less porous structure alone it is evident that a piece of young and thrifty oak is stronger than the porous wood of an old or stunted tree, or that a Georgia or long-leaf pine excels white pine in weight and strength.

Keeping especially in mind the arrangement and direction of the fibres of wood, it is clear at once why knots and "cross-grain" interfere with the strength of timber. It is due to the structural peculiarities that "honeycombing" occurs in rapid seasoning, that checks or cracks extend radially and follow pith rays, that tangent or "bastard" cut stock shrinks and warps more than that which is quarter-sawn. These same peculiarities enable oak to take a better finish than basswood or coarse-grained pine.

Structure of Wood

The softwoods are made up chiefly of tracheids, or vertical cells closed at the ends, and of the relatively short parenchyma cells of the medullary rays which extend radially from the heart of the tree. The course of the tracheids and the rays are at right angles to each other. Although the tracheids have their permeable portions or pits in their walls, liquids cannot pass through them with the greatest ease. The softwoods do not contain "pores" or vessels and are therefore called "non-porous" woods.

The hardwoods are not so simple in structure as softwoods. They contain not only rays, and in many cases tracheids, but also thick-walled cells called fibres and wood parenchyma for the storage of such foods as starches and sugars. The principal structural features of the hardwoods are the pores or vessels. These are long tubes, the segments of which are made up of cells which have lost their end walls and joined end to end, forming continuous "pipe lines" from the roots to the leaves in the tree. Since they possess pores or vessels, the hardwoods are called "porous" woods.

Red oak is an excellent example of a porous wood. In white oak the vessels of the heartwood especially are closed, very generally by ingrowths called tyloses. This probably explains why red oak dries more easily and rapidly than white oak.

The red and black gums are perhaps the simplest of the hardwoods in structure. They are termed "diffuse porous" woods because of the numerous scattered pores they contain. They have only vessels, wood fibres, and a few parenchyma cells. The medullary rays, although present, are scarcely visible in most instances. The vessels are in many cases open, and might be expected to offer relatively little resistance to drying.

Properties of Wood

Certain general properties of wood may be discussed briefly. We know that wood substance has the property of taking in moisture from the air until some balance is reached between the humidity of the air and the moisture in the wood. This moisture which goes into the cell walls hygroscopic moisture, and the property which the wood substance has of taking on hygroscopic moisture is termed hygroscopicity. Usually wood contains not only hygroscopic moisture but also more or less free water in the cell cavities. Especially is this true of sapwood. The free water usually dries out quite rapidly with little or no shrinkage or other physical change.

In certain woods—for example, Eucalyptus globulus and possibly some oaks—shrinkage begins almost at once, thus introducing a factor at the very start of the seasoning process which makes these woods very refractory.

The cell walls of some species, including the two already mentioned, such as Western red cedar and redwood, become soft and plastic when hot and moist. If the fibres are hot enough and very wet, they are not strong enough to withstand the resulting force of the atmospheric pressure and the tensile force exerted by the departing free water, and the result is that the cells actually collapse.

In general, however, the hygroscopic moisture necessary to saturate the cell walls is termed the "fibre saturation point." This amount has been found to be from 25 to 30 per cent of the dry wood weight. Unlike Eucalyptus globulus and certain oaks, the gums do not begin to shrink until the moisture content has been reduced to about 30 per cent of the dry wood weight. These woods are not subject to collapse, although their fibres become very plastic while hot and moist.

Upon the peculiar properties of each wood depends the difficulty or ease of the seasoning process.

Classes of Trees

The timber of the United States is furnished by three well-defined classes of trees: (1) The needle-leaved, naked-seeded conifers, such as pine, cedar, etc., (2) the broad-leaved trees such as oak poplar, etc., and (3) to an inferior extent by the (one-seed leaf) palms, yuccas, and their allies, which are confined to the most southern parts of the country.

Broad-leaved trees are also known as deciduous trees, although, especially in warm countries, many of them are evergreen, while the needle-leaved trees (conifers) are commonly termed "evergreens," although the larch, bald cypress, and others shed their leaves every fall, and even the names "broad-leaved" and "coniferous," though perhaps the most satisfactory, are not at all exact, for the conifer "ginkgo" has broad leaves and bears no cones.

Among the woodsmen, the woods of broad-leaved trees are known as "hardwoods," though poplar is as soft as pine, and the "coniferous woods" are known as "softwoods," notwithstanding the fact that yew ranks high in hardness even when compared with "hardwoods."

Both in the number of different kinds of trees or species and still more in the importance of their product, the conifers and broad-leaved trees far excel the palms and their relatives.

In the manner of their growth both the conifers and broad-leaved trees behave alike, adding each year a new layer of wood, which covers the old wood in all parts of the stem and limbs. Thus the trunk continues to grow in thickness throughout the life of the tree by additions (annual rings), which in temperate climates are, barring accidents, accurate records of the tree. With the palms and their relatives the stem remains generally of the same diameter, the tree of a hundred years old being as thick as it was at ten years, the growth of these being only at the top. Even where a peripheral increase takes place, as in the yuccas, the wood is not laid on in well-defined layers for the structure remains irregular throughout. Though alike in the manner of their growth, and therefore similar in their general make-up, conifers and broad-leaved trees differ markedly in the details of their structure and the character of their wood.

The wood of all conifers is very simple in its structure, the fibres composing the main part of the wood all being alike and their arrangement regular. The wood of the broad-leaved trees is complex in structure; it is made up of different kinds of cells and fibres and lacks the regularity of arrangement so noticeable in the conifers. This difference is so great that in a study of wood structure it is best to consider the two kinds separately.

In this country the great variety of woods, and especially of useful woods, often makes the mere distinction of the kind or species of tree most difficult. Thus there are at least eight pines of the thirty-five native ones in the market, some of which so closely resemble each other in their minute structure that one can hardly tell them apart, and yet they differ in quality and are often mixed or confounded in the trade. Of the thirty-six oaks, of which probably not less than six or eight are marketed, we can readily recognize by means of their minute anatomy at least two tribes—the white and black oaks. The same is true of the eleven kinds of hickory, the six kinds of ash, etc., etc.

The list of names of all trees indigenous to the United States, as enumerated by the United States Forest Service, is 495 in number, the designation of "tree" being applied to all woody plants which produce naturally in their native habitat one main, erect stem, bearing a definite crown, no matter what size they attain.

Timber is produced only by the Spermatophyta, or seed-bearing plants, which are subdivided into the Gymnosperms (conifers), and Angiosperms (broad-leaved). The conifer or cone-bearing tree, to which belong the pines, larches, and firs, is one of the three natural orders of Gymnosperms. These are generally classed as "softwoods," and are more extensively scattered and more generally used than any other class of timber, and are simple and regular in structure. The so-called "hardwoods" are "Dicotyledons" or broad-leaved trees, a subdivision of the Angiosperms. They are generally of slower growth, and produce harder timber than the conifers, but not necessarily so. Basswood, poplar, sycamore, and some of the gums, though classed with the hardwoods, are not nearly as hard as some of the pines.

SECTION II

CONIFEROUS TREES

WOOD OF THE CONIFEROUS TREES

Examining a smooth cross-section or end face of a well-grown log of Georgia pine, we distinguish an envelope of reddish, scaly bark, a small, whitish pith at the center, and between these the wood in a great number of concentric rings.

Bark and Pith

The bark of a pine stem is thickest and roughest near the base, decreases rapidly in thickness from one to one-half inches at the stump to one-tenth inch near the top of the tree, and forms in general about ten to fifteen per cent of the entire trunk. The pith is quite thick, usually one-eighth to one-fifth inch in southern species, though much less so in white pine, and is very thin, one-fifteenth to one twenty-fifth inch in cypress, cedar, and larch.

In woods with a thick pith, the pith is finest at the stump, grows rapidly thicker toward the top, and becomes thinner again in the crown and limbs, the first one to five rings adjoining it behaving similarly.

What is called the pith was once the seedling tree, and in many of the pines and firs, especially after they have been seasoning for a good while, this is distinctly noticeable in the center of the log, and detaches itself from the surrounding wood.

Sap and Heartwood

Wood is composed of duramen or heartwood, and alburnum or sapwood, and when dry consists approximately of 49 per cent by weight of carbon, 6 per cent of hydrogen, 44 per cent of oxygen, and 1 per cent of ash, which is fairly uniform for all species. The sapwood is the external and youngest portion of the tree, and often constitutes a very considerable proportion of it. It lies next the bark, and after a course of years, sometimes many, as in the case of oaks, sometimes few, as in the case of firs, it becomes hardened and ultimately forms the duramen or heartwood. Sapwood is generally of a white or light color, almost invariably lighter in color than the heartwood, and is very conspicuous in the darker-colored woods, as for instance the yellow sapwood of mahogany and similiar colored woods, and the reddish brown heartwood; or the yellow sapwood of Lignum-vitae and the dark green heartwood. Sapwood forms a much larger proportion of some trees than others, but being on the outer circumference it always forms a large proportion of the timber, and even in sound, hard pine will be from 40 per cent to 60 per cent of the tree and in some cases much more. It is really imperfect wood, while the duramen or heartwood is the perfect wood; the heartwood of the mature tree was the sapwood of its earlier years. Young trees when cut down are almost all sapwood, and practically useless as good, sound timber; it is, however, through the sapwood that the life-giving juices which sustain the tree arise from the soil, and if the sapwood be cut through, as is done when "girdling," the tree quickly dies, as it can derive no further nourishment from the soil. Although absolutely necessary to the growing tree, sapwood is often objectionable to the user, as it is the first part to decay. In this sapwood many cells are active, store up starch, and otherwise assist in the life processes of the tree, although only the last or outer layer of cells forms the growing part, and the true life of the tree.

The duramen or heartwood is the inner, darker part of the log. In the heartwood all the cells are lifeless cases, and serve only the mechanical function of keeping the tree from breaking under its own great weight or from being laid low by the winds. The darker color of the heartwood is due to infiltration of chemical substances into the cell walls, but the cavities of the cells in pine are not filled up, as is sometimes believed, nor do their walls grow thicker, nor are the walls any more liquified than in the sapwood.

Sapwood varies in width and in the number of rings which it contains even in different parts of the same tree. The same year's growth which is sapwood in one part of a disk may be heartwood in another. Sapwood is widest in the main part of the stem and often varies within considerable limits and without apparent regularity. Generally, it becomes narrower toward the top and in the limbs, its width varying with the diameter, and being the least in a given disk on the side which has the shortest radius. Sapwood of old and stunted pines is composed of more rings than that of young and thrifty specimens. Thus in a pine two hundred and fifty years old a layer of wood or an annual ring does not change from sapwood to heartwood until seventy or eighty years after it is formed, while in a tree one hundred years old or less it remains sapwood only from thirty to sixty years.

The width of the sapwood varies considerably for different kinds of pine. It is small for long-leaf and white pine and great for loblolly and Norway pines. Occupying the peripheral part of the trunk, the proportion which it forms of the entire mass of the stem is always great. Thus even in old long-leaf pines, the sapwood forms 40 per cent of the merchantable log, while in the loblolly and in all young trees the sapwood forms the bulk of the wood.

The Annual or Yearly Rings

The concentric annual or yearly rings which appear on the end face of a log are cross-sections of so many thin layers of wood. Each such layer forms an envelope around its inner neighbor, and is in turn covered by the adjoining layer without, so that the whole stem is built up of a series of thin, hollow cylinders, or rather cones.

A new layer of wood is formed each season, covering the entire stem, as well as all the living branches. The thickness of this layer or the width of the yearly ring varies greatly in different trees, and also in different parts of the same tree.

In a normally-grown, thrifty pine log the rings are widest near the pith, growing more and more narrow toward the bark. Thus the central twenty rings in a disk of an old long-leaf pine may each be one-eighth to one-sixth inch wide, while the twenty rings next to the bark may average only one-thirtieth inch.

In our forest trees, rings of one-half inch in width occur only near the center in disks of very thrifty trees, of both conifers and hardwoods. One-twelfth inch represents good, thrifty growth, and the minimum width of one two hundred inch is often seen in stunted spruce and pine. The average width of rings in well-grown, old white pine will vary from one-twelfth to one-eighteenth inch, while in the slower growing long-leaf pine it may be one twenty-fifth to one-thirtieth of an inch. The same layer of wood is widest near the stump in very thrifty young trees, especially if grown in the open park; but in old forest trees the same year's growth is wider at the upper part of the tree, being narrowest near the stump, and often also near the very tip of the stem. Generally the rings are widest near the center, growing narrower toward the bark.

In logs from stunted trees the order is often reversed, the interior rings being thin and the outer rings widest. Frequently, too, zones or bands of very narrow rings, representing unfavorable periods of growth, disturb the general regularity.

Few trees, even among pines, furnish a log with truly circular cross-section. Usually it is an oval, and at the stump commonly quite an irregular figure. Moreover, even in very regular or circular disks the pith is rarely in the center, and frequently one radius is conspicuously longer than its opposite, the width of some rings, if not all, being greater on one side than on the other. This is nearly always so in the limbs, the lower radius exceeding the upper. In extreme cases, especially in the limbs, a ring is frequently conspicuous on one side, and almost or entirely lost to view on the other. Where the rings are extremely narrow, the dark portion of the ring is often wanting, the color being quite uniform and light. The greater regularity or irregularity of the annual rings has much to do with the technical qualities of the timber.

Spring- and Summer-Wood

Examining the rings more closely, it is noticed that each ring is made up of an inner, softer, light-colored and an outer, or peripheral, firmer and darker-colored portion. Being formed in the forepart of the season, the inner, light-colored part is termed spring-wood, the outer, darker-portioned being the summer-wood of the ring. Since the latter is very heavy and firm it determines to a very large extent the weight and strength of the wood, and as its darker color influences the shade of color of the entire piece of wood, this color effect becomes a valuable aid in distinguishing heavy and strong from light and soft pine wood.

In most hard pines, like the long-leaf, the dark summer-wood appears as a distinct band, so that the yearly ring is composed of two sharply defined bands—an inner, the spring-wood, and an outer, the summer-wood. But in some cases, even in hard pines, and normally in the woods of white pines, the spring-wood passes gradually into the darker summer-wood, so that a darkly defined line occurs only where the spring-wood of one ring abuts against the summer-wood of its neighbor. It is this clearly defined line which enables the eye to distinguish even the very narrow lines in old pines and spruces.

Fig. 1. Board of Pine. CS, cross-section; RS, radial section; TS, tangential section; sw, summer-wood; spw, spring-wood.

In some cases, especially in the trunks of Southern pines, and normally on the lower side of pine limbs, there occur dark bands of wood in the spring-wood portion of the ring, giving rise to false rings, which mislead in a superficial counting of rings. In the disks cut from limbs these dark bands often occupy the greater part of the ring, and appear as "lunes," or sickle-shaped figures. The wood of these dark bands is similar to that of the true summer-wood. The cells have thick walls, but usually the compressed or flattened form. Normally, the summer-wood forms a greater proportion of the rings in the part of the tree formed during the period of thriftiest growth. In an old tree this proportion is very small in the first two to five rings about the pith, and also in the part next to the bark, the intermediate part showing a greater proportion of summer-wood. It is also greatest in a disk taken from near the stump, and decreases upward in the stem, thus fully accounting for the difference in weight and firmness of the wood of these different parts.

In the long-leaf pine the summer-wood often forms scarcely ten per cent of the wood in the central five rings; forty to fifty per cent of the next one hundred rings, about thirty per cent of the next fifty, and only about twenty per cent in the fifty rings next to the bark. It averages forty-five per cent of the wood of the stump and only twenty-four per cent of that of the top.

Sawing the log into boards, the yearly rings are represented on the board faces of the middle board (radial sections) by narrow parallel strips ([see Fig. 1]), an inner, lighter stripe and its outer, darker neighbor always corresponding to one annual ring.

On the faces of the boards nearest the slab (tangential or bastard boards) the several years' growth should also appear as parallel, but much broader stripes. This they do if the log is short and very perfect. Usually a variety of pleasing patterns is displayed on the boards, depending on the position of the saw cut and on the regularity of growth of the log ([see Fig. 1]). Where the cut passes through a prominence (bump or crook) of the log, irregular, concentric circlets and ovals are produced, and on almost all tangent boards arrow or V-shaped forms occur.

Anatomical Structure

Holding a well-smoothed disk or cross-section one-eighth inch thick toward the light, it is readily seen that pine wood is a very porous structure. If viewed with a strong magnifier, the little tubes, especially in the spring-wood of the rings, are easily distinguished, and their arrangement in regular, straight, radial rows is apparent.

Fig. 2. Wood of Spruce. 1, natural size; 2, small part of one ring magnified 100 times. The vertical tubes are wood fibres, in this case all "tracheids." m, medullary or pith ray; n, transverse tracheids of ray; a, b, and c, bordered pits of the tracheids, more enlarged.

Scattered through the summer-wood portion of the rings, numerous irregular grayish dots (the resin ducts) disturb the uniformity and regularity of the structure. Magnified one hundred times, a piece of spruce, which is similar to pine, presents a picture like that shown in [Fig. 2]. Only short pieces of the tubes or cells of which the wood is composed are represented in the picture. The total length of these fibres is from one-twentieth to one-fifth inch, being the smallest near the pith, and is fifty to one hundred times as great as their width (see [Fig. 3]). They are tapered and closed at their ends, polygonal or rounded and thin-walled, with large cavity, lumen or internal space in the spring-wood, and thick-walled and flattened radially, with the internal space or lumen much reduced in the summer-wood (see right-hand portion of [Fig. 2]). This flattening, together with the thicker walls of the cells, which reduces the lumen, causes the greater firmness and darker color of the summer-wood. There is more material in the same volume. As shown in the figure, the tubes, cells or "tracheids" are decorated on their walls by circlet-like structures, the "bordered pits," sections of which are seen more magnified as a, b, and c, [Fig. 2]. These pits are in the nature of pores, covered by very thin membranes, and serve as waterways between the cells or tracheids. The dark lines on the side of the smaller piece (1, [Fig. 2]) appear when magnified (in 2, [Fig. 2]) as tiers of eight to ten rows of cells, which run radially (parallel to the rows of tubes or tracheids), and are seen as bands on the radial face and as rows of pores on the tangential face. These bands or tiers of cell rows are the medullary rays or pith rays, and are common to all our lumber woods.

In the pines and other conifers they are quite small, but they can readily be seen even without a magnifier. If a radial surface of split-wood (not smoothed) is examined, the entire radial face will be seen almost covered with these tiny structures, which appear as fine but conspicuous cross-lines. As shown in [Fig. 2], the cells of the medullary or pith are smaller and very much shorter than the wood fibre or tracheids, and their long axis is at right angles to that of the fiber.

In pines and spruces the cells of the upper and lower rows of each tier or pith ray have "bordered" pits, like those of the wood fibre or tracheids proper, but the cells of the intermediate rows in the rays of cedars, etc., have only "simple" pits, i.e., pits devoid of the saucer-like "border" or rim. In pine, many of the pith rays are larger than the majority, each containing a whitish line, the horizontal resin duct, which, though much smaller, resembles the vertical ducts on the cross-section. The larger vertical resin ducts are best observed on removal of the bark from a fresh piece of white pine cut in the winter where they appear as conspicuous white lines, extending often for many inches up and down the stem. Neither the horizontal nor the vertical resin ducts are vessels or cells, but are openings between cells, i.e., intercellular spaces, in which the resin accumulates, freely oozing out when the ducts of a fresh piece of sapwood are cut. They are present only in our coniferous woods, and even here they are restricted to pine, spruce, and larch, and are normally absent in fir, cedar, cypress, and yew. Altogether, the structure of coniferous woods is very simple and regular, the bulk being made up of the small fibres called tracheids, the disturbing elements of pith rays and resin ducts being insignificant, and hence the great uniformity and great technical value of coniferous woods.

Fig. 3. Group of Fibres from Pine Wood. Partly schematic. The little circles are "border pits" (see [Fig. 2], a-c). The transverse rows of square pits indicate the places of contact of these fibres and the cells of the neighboring pith rays. Magnified about 25 times.

LIST OF IMPORTANT CONIFEROUS WOODS

CEDAR

Light soft, stiff, not strong, of fine texture. Sap- and heartwood distinct, the former lighter, the latter a dull grayish brown or red. The wood seasons rapidly, shrinks and checks but little, and is very durable in contact with the soil. Used like soft pine, but owing to its great durability preferred for shingles, etc. Cedars usually occur scattered, but they form in certain localities forests of considerable extent.

(a) White Cedars

1. White Cedar (Thuya occidentalis) (Arborvitæ, Tree of Life). Heartwood light yellowish brown, sapwood nearly white. Wood light, soft, not strong, of fine texture, very durable in contact with the soil, very fragrant. Scattered along streams and lakes, frequently covering extensive swamps; rarely large enough for lumber, but commonly used for fence posts, rails, railway ties, and shingles. This species has been extensively cultivated as an ornamental tree for at least a century. Maine to Minnesota and northward.

2. Canoe Cedar (Thuya gigantea) (Red Cedar of the West). In Oregon and Washington a very large tree, covering extensive swamps; in the mountains much smaller, skirting the water courses. An important lumber tree. The wood takes a fine polish; suitable for interior finishing, as there is much variety of shading in the color. Washington to northern California and eastward to Montana.

3. White Cedar (Chamæcyparis thyoides). Medium-sized tree. Heartwood light brown with rose tinge, sapwood paler. Wood light, soft, not strong, close-grained, easily worked, very durable in contact with the soil and very fragrant. Used in boatbuilding cooperage, interior finish, fence posts, railway ties, etc. Along the coast from Maine to Mississippi.

4. White Cedar (Chamæcyparis Lawsoniana) (Port Orford Cedar, Oregon Cedar, Lawson's Cypress, Ginger Pine). A very large tree. A fine, close-grained, yellowish-white, durable timber, elastic, easily worked, free of knots, and fragrant. Extensively cut for lumber; heavier and stronger than any of the preceding. Along the coast line of Oregon.

5. White Cedar (Libocedrus decurrens) (Incense Cedar). A large tree, abundantly scattered among pine and fir. Wood fine-grained. Cascades and Sierra Nevada Mountains of Oregon and California.

6. Yellow Cedar (Cupressus nootkatensis) (Alaska Cedar, Alaska Cypress). A very large tree, much used for panelling and furniture. A fine, close-grained, yellowish white, durable timber, easily worked. Along the coast line of Oregon north.

(b) Red Cedars

7. Red Cedar (Juniperus Virginiana) (Savin Juniper, Juniper, Red Juniper, Juniper Bush, Pencil Cedar). Heartwood dull red color, thin sapwood nearly white. Close even grain, compact structure. Wood light, soft, weak, brittle, easily worked, durable in contact with the soil, and fragrant. Used for ties, posts, interior finish, pencil cases, cigar boxes, silos, tanks, and especially for lead pencils, for which purpose alone several million feet are cut each year. A small to medium-sized tree scattered through the forests, or in the West sparsely covering extensive areas (cedar brakes). The red cedar is the most widely distributed conifer of the United States, occurring from the Atlantic to the Pacific, and from Florida to Minnesota. Attains a suitable size for lumber only in the Southern, and more especially the Gulf States.

8. Red Cedar (Juniperus communis) (Ground Cedar). Small-sized tree, its maximum height being about 25 feet. It is found widely distributed throughout the Northern hemisphere. Wood in its quality similar to the preceding. The fruit of this species is gathered in large quantities and used in the manufacture of gin; whose peculiar flavor and medicinal properties are due to the oil of Juniper berries, which is secured by adding the crushed fruit to undistilled grain spirit, or by allowing the vapor to pass over it before condensation. Used locally for construction purposes, fence posts, etc. Ranges from Greenland to Alaska, in the East, southward to Pennsylvania and northern Nebraska; in the Rocky Mountains to Texas, Mexico, and Arizona.

9. Redwood (Sequoia sempervirens) (Sequoia, California Redwood, Coast Redwood). Wood in its quality and uses like white cedar. Thick, red heartwood, changing to reddish brown when seasoned. Thin sapwood, nearly white, coarse, straight grain, compact structure. Light, not strong, soft, very durable in contact with the soil, not resinous, easily worked, does not burn easily, receives high polish. Used for timber, shingles, flumes, fence posts, coffins, railway ties, water pipes, interior decorations, and cabinetmaking. A very large tree, limited to the coast ranges of California, and forming considerable forests, which are rapidly being converted into lumber.

CYPRESS

10. Cypress (Taxodium distinchum) (Bald Cypress, Black, White, and Red Cypress, Pecky Cypress). Wood in its appearance, quality, and uses similar to white cedar. "Black" and "White Cypress" are heavy and light forms of the same species. Heartwood brownish; sapwood nearly white. Wood close, straight-grain, frequently full of small holes caused by disease known as "pecky cypress." Greasy appearance and feeling. Wood light, soft, not strong, durable in contact with the soil, takes a fine polish. Green wood often very heavy. Used for carpentry, building construction, shingles, cooperage, railway ties, silos, tanks, vehicles, and washing machines. The cypress is a large, deciduous tree, inhabiting swampy lands, and along rivers and coasts of the Southern parts of the United States. Grows to a height of 150 feet and 12 feet in diameter.

FIR

This name is frequently applied to wood and to trees which are not fir; most commonly to spruce, but also, especially in English markets, to pine. It resembles spruce, but is easily distinguished from it, as well as from pine and larch, by the absence of resin ducts. Quality, uses, and habits similar to spruce.

11. Balsam Fir (Abies balsamea) (Balsam, Fir Tree, Balm of Gilead Fir). Heartwood white to brownish; sapwood lighter color; coarse-grained, compact structure, satiny. Wood light, not durable or strong, resinous, easily split. Used for boxes, crates, doors, millwork, cheap lumber, paper pulp. Inferior to white pine or spruce, yet often mixed and sold with these species in the lumber market. A medium-sized tree scattered throughout the northern pineries, and cut in lumber operations whenever of sufficient size. Minnesota to Maine and northward.

12. White Fir (Abies grandis and Abies concolor). Medium- to very large-sized tree, forming an important part of most of the Western mountain forests, and furnishes much of the lumber of the respective regions. The former occurs from Vancouver to California, and the latter from Oregon to Arizona and eastward to Colorado and Mexico. The wood is soft and light, coarse-grained, not unlike the "Swiss pine" of Europe, but darker and firmer, and is not suitable for any purpose requiring strength. It is used for boxes, barrels, and to a small extent for wood pulp.

13. White Fir (Abies amabalis). Good-sized tree, often forming extensive mountain forests. Wood similar in quality and uses to Abies grandis. Cascade Mountains of Washington and Oregon.

14. Red Fir (Abies nobilis) (Noble Fir) (not to be confounded with Douglas spruce. See No. 40). Large to very large-sized tree, forming extensive forests on the slope of the mountains between 3,000 and 4,000 feet elevation. Cascade Mountains of Oregon.

15. Red Fir (Abies magnifica). Very large-sized tree, forming forests about the base of Mount Shasta. Sierra Nevada Mountains of California, from Mount Shasta southward.

HEMLOCK

Light to medium weight, soft, stiff, but brittle, commonly cross-grained, rough and splintery. Sapwood and heartwood not well defined. The wood of a light reddish-gray color, free from resin ducts, moderately durable, shrinks and warps considerably in drying, wears rough, retains nails firmly. Used principally for dimension stuff and timbers. Hemlocks are medium- to large-sized trees, commonly scattered among broad-leaved trees and conifers, but often forming forests of almost pure growth.

16. Hemlock (Tsuga canadensis) (Hemlock Spruce, Peruche). Medium-sized tree, furnishes almost all the hemlock of the Eastern market. Maine to Wisconsin, also following the Alleghanies southward to Georgia and Alabama.

17. Hemlock (Tsuga mertensiana). Large-sized tree, wood claimed to be heavier and harder than the Eastern species and of superior quality. Used for pulp wood, floors, panels, and newels. It is not suitable for heavy construction, especially where exposed to the weather, it is straight in grain and will take a good polish. Not adapted for use partly in and partly out of the ground; in fresh water as piles will last about ten years, but as it is softer than fir it is less able to stand driving successfully. Washington to California and eastward to Montana.

LARCH or TAMARACK

Wood like the best of hard pine both in appearance, quality, and uses, and owing to its great durability somewhat preferred in shipbuilding, for telegraph poles, and railway ties. In its structure it resembles spruce. The larches are deciduous trees, occasionally covering considerable areas, but usually scattered among other conifers.

18. Tamarack (Larix laricina var. Americana) (Larch, Black Larch, American Larch, Hacmatac). Heartwood light brown in color, sapwood nearly white, coarse conspicuous grain, compact structure, annual rings pronounced. Wood heavy, hard, very strong, durable in contact with the soil. Used for railway ties, fence posts, sills, ship timbers, telegraph poles, flagstaffs. Medium-sized tree, often covering swamps, in which case it is smaller and of poor quality. Maine to Minnesota, and southward to Pennsylvania.

19. Tamarack (Larix occidentalis) (Western Larch, Larch). Large-sized trees, scattered, locally abundant. Is little inferior to oak in strength and durability. Heartwood of a light brown color with lighter sapwood, has a fine, slightly satiny grain, and is fairly free from knots; the annual rings are distant. Used for railway ties and shipbuilding. Washington and Oregon to Montana.

PINE

Very variable, very light and soft in "soft" pine, such as white pine; of medium weight to heavy and quite hard in "hard" pine, of which the long-leaf or Georgia pine is the extreme form. Usually it is stiff, quite strong, of even texture, and more or less resinous. The sapwood is yellowish white; the heartwood orange brown. Pine shrinks moderately, seasons rapidly and without much injury; it works easily, is never too hard to nail (unlike oak or hickory); it is mostly quite durable when in contact with the soil, and if well seasoned is not subject to the attacks of boring insects. The heavier the wood, the darker, stronger, and harder it is, and the more it shrinks and checks when seasoning. Pine is used more extensively than any other wood. It is the principal wood in carpentry, as well as in all heavy construction, bridges, trestles, etc. It is also used in almost every other wood industry; for spars, masts, planks, and timbers in shipbuilding, in car and wagon construction, in cooperage and woodenware; for crates and boxes, in furniture work, for toys and patterns, water pipes, excelsior, etc. Pines are usually large-sized trees with few branches, the straight, cylindrical, useful stem forming by far the greatest part of the tree. They occur gregariously, forming vast forests, a fact which greatly facilitates their exploitation. Of the many special terms applied to pine as lumber, denoting sometimes differences in quality, the following deserve attention: "White pine," "pumpkin pine," "soft pine," in the Eastern markets refer to the wood of the white pine (Pinus strobus), and on the Pacific Coast to that of the sugar pine (Pinus lambertiana). "Yellow pine" is applied in the trade to all the Southern lumber pines; in the Northwest it is also applied to the pitch pine (Pinus regida); in the West it refers mostly to the bull pine (Pinus ponderosa). "Yellow long-leaf pine" (Georgia pine), chiefly used in advertisements, refers to the long-leaf Pine (Pinus palustris).

(a) Soft Pines

20. White Pine (Pinus strobus) (Soft Pine, Pumpkin Pine, Weymouth Pine, Yellow Deal). Large to very large-sized tree, reaching a height of 80 to 100 feet or more, and in some instances 7 or 8 feet in diameter. For the last fifty years the most important timber tree of the United States, furnishing the best quality of soft pine. Heartwood cream white; sapwood nearly white. Close straight grain, compact structure; comparatively free from knots and resin. Soft, uniform; seasons well; easy to work; nails without splitting; fairly durable in contact with the soil; and shrinks less than other species of pine. Paints well. Used for carpentry, construction, building, spars, masts, matches, boxes, etc., etc., etc.

21. Sugar Pine (Pinus lambertiana) (White Pine, Pumpkin Pine, Soft Pine). A very large tree, forming extensive forests in the Rocky Mountains and furnishing most of the timber of the western United States. It is confined to Oregon and California, and grows at from 1,500 to 8,000 feet above sea level. Has an average height of 150 to 175 feet and a diameter of 4 to 5 feet, with a maximum height of 235 feet and 12 feet in diameter. The wood is soft, durable, straight-grained, easily worked, very resinous, and has a satiny luster which makes it appreciated for interior work. It is extensively used for doors, blinds, sashes, and interior finish, also for druggists' drawers, owing to its freedom from odor, for oars, mouldings, shipbuilding, cooperage, shingles, and fruit boxes. Oregon and California.

22. White Pine (Pinus monticolo). A large tree, at home in Montana, Idaho, and the Pacific States. Most common and locally used in northern Idaho.

23. White Pine (Pinus flexilis). A small-sized tree, forming mountain forests of considerable extent and locally used. Eastern Rocky Mountain slopes, Montana to New Mexico.

(b) Hard Pines

24. Long-Leaf Pine (Pinus palustris) (Georgia Pine, Southern Pine, Yellow Pine, Southern Hard Pine, Long-straw Pine, etc.). Large-sized tree. This species furnishes the hardest and most durable as well as one of the strongest pine timbers in the market. Heartwood orange, sapwood lighter color, the annual rings are strongly marked, and it is full of resinous matter, making it very durable, but difficult to work. It is hard, dense, and strong, fairly free from knots, straight-grained, and one of the best timbers for heavy engineering work where great strength, long span, and durability are required. Used for heavy construction, shipbuilding, cars, docks, beams, ties, flooring, and interior decoration. Coast region from North Carolina to Texas.

25. Bull Pine (Pinus ponderosa) (Yellow Pine, Western Yellow Pine, Western Pine, Western White Pine, California White Pine). Medium- to very large-sized tree, forming extensive forests in the Pacific and Rocky Mountain regions. Heartwood reddish brown, sapwood yellowish white, and there is often a good deal of it. The resinous smell of the wood is very remarkable. It is extensively used for beams, flooring, ceilings, and building work generally.

26. Bull Pine (Pinus Jeffreyi) (Black Pine). Large-sized tree, wood resembles Pinus ponderosa and replacing same at high altitudes. Used locally in California.

27. Loblolly Pine (Pinus tæda) (Slash Pine, Old Field Pine, Rosemary Pine, Sap Pine, Short-straw Pine). A large-sized tree, forms extensive forests. Wider-ringed, coarser, lighter, softer, with more sapwood than the long-leaf pine, but the two are often confounded in the market. The more Northern tree produces lumber which is weak, brittle, coarse-grained, and not durable, the Southern tree produces a better quality wood. Both are very resinous. This is the common lumber pine from Virginia to South Carolina, and is found extensively in Arkansas and Texas. Southern States, Virginia to Texas and Arkansas.

28. Norway Pine (Pinus resinosa) (American Red Pine, Canadian Pine). Large-sized tree, never forming forests, usually scattered or in small groves, together with white pine. Largely sapwood and hence not durable. Heartwood reddish white, with fine, clear grain, fairly tough and elastic, not liable to warp and split. Used for building construction, bridges, piles, masts, and spars. Minnesota to Michigan; also in New England to Pennsylvania.

29. Short-Leaf Pine (Pinus echinata) (Slash Pine, Spruce Pine, Carolina Pine, Yellow Pine, Old Field Pine, Hard Pine). A medium- to large-sized tree, resembling loblolly pine, often approaches in its wood the Norway pine. Heartwood orange, sapwood lighter; compact structure, apt to be variable in appearance in cross-section. Wood usually hard, tough, strong, durable, resinous. A valuable timber tree, sometimes worked for turpentine. Used for heavy construction, shipbuilding, cars, docks, beams, ties, flooring, and house trim. Pinus echinata, palustris, and tæda are very similar in character, of thin wood and very difficult to distinguish one from another. As a rule, however, palustris (Long-leaf Pine) has the smallest and most uniform growth rings, and Pinus tæda (Loblolly Pine) has the largest. All are apt to be bunched together in the lumber market as Southern Hard Pine. All are used for the same purposes. Short-leaf is the common lumber pine of Missouri and Arkansas. North Carolina to Texas and Missouri.

30. Cuban Pine (Pinus cubensis) (Slash Pine, Swamp Pine, Bastard Pine, Meadow Pine). Resembles long-leaf pine, but commonly has a wider sapwood and coarser grain. Does not enter the markets to any extent. Along the coast from South Carolina to Louisiana.

31. Pitch Pine (Pinus rigida) (Torch Pine). A small to medium-sized tree. Heartwood light brown or red, sapwood yellowish white. Wood light, soft, not strong, coarse-grained, durable, very resinous. Used locally for lumber, fuel, and charcoal. Coast regions from New York to Georgia, and along the mountains to Kentucky.

32. Black Pine (Pinus murryana) (Lodge-pole Pine, Tamarack). Small-sized tree. Rocky Mountains and Pacific regions.

33. Jersey Pine (Pinus inops var. Virginiana) (Scrub Pine). Small-sized tree. Along the coast from New York to Georgia and along the mountains to Kentucky.

34. Gray Pine (Pinus divaricata var. banksiana) (Scrub Pine, Jack Pine). Medium- to large-sized tree. Heartwood pale brown, rarely yellow; sapwood nearly white. Wood light, soft, not strong, close-grained. Used for fuel, railway ties, and fence posts. In days gone by the Indians preferred this species for frames of canoes. Maine, Vermont, and Michigan to Minnesota.

REDWOOD (See Cedar)

SPRUCE

Resembles soft pine, is light, very soft, stiff, moderately strong, less resinous than pine; has no distinct heartwood, and is of whitish color. Used like soft pine, but also employed as resonance wood in musical instruments and preferred for paper pulp. Spruces, like pines, form extensive forests. They are more frugal, thrive on thinner soils, and bear more shade, but usually require a more humid climate. "Black" and "White" spruce as applied by lumbermen usually refer to narrow and wide-ringed forms of black spruce (Picea nigra).

35. Black Spruce (Picea nigra var. mariana). Medium-sized tree, forms extensive forests in northwestern United States and in British America; occurs scattered or in groves, especially in low lands throughout the northern pineries. Important lumber tree in eastern United States. Heartwood pale, often with reddish tinge; sapwood pure white. Wood light, soft, not strong. Chiefly used for manufacture of paper pulp, and great quantities of this as well as Picea alba are used for this purpose. Used also for sounding boards for pianos, violins, etc. Maine to Minnesota, British America, and in the Alleghanies to North Carolina.

36. White Spruce (Picea canadensis var. alba). Medium- to large-sized tree. Heartwood light yellow; sapwood nearly white. Generally associated with the preceding. Most abundant along streams and lakes, grows largest in Montana and forms the most important tree of the sub-arctic forest of British America. Used largely for floors, joists, doors, sashes, mouldings, and panel work, rapidly superceding Pinus strobus for building purposes. It is very similar to Norway pine, excels it in toughness, is rather less durable and dense, and more liable to warp in seasoning. Northern United States from Maine to Minnesota, also from Montana to Pacific, British America.

37. White Spruce (Picea engelmanni). Medium- to large-sized tree, forming extensive forests at elevations from 5,000 to 10,000 feet above sea level; resembles the preceding, but occupies a different station. A very important timber tree in the central and southern parts of the Rocky Mountains. Rocky Mountains from Mexico to Montana.

38. Tide-Land Spruce (Picea sitchensis) (Sitka Spruce). A large-sized tree, forming an extensive coast-belt forest. Used extensively for all classes of cooperage and woodenware on the Pacific Coast. Along the sea-coast from Alaska to central California.

39. Red Spruce (Picea rubens). Medium-sized tree, generally associated with Picea nigra and occurs scattered throughout the northern pineries. Heartwood reddish; sapwood lighter color, straight-grained, compact structure. Wood light, soft, not strong, elastic, resonant, not durable when exposed. Used for flooring, carpentry, shipbuilding, piles, posts, railway ties, paddles, oars, sounding boards, paper pulp, and musical instruments. Montana to Pacific, British America.

BASTARD SPRUCE

Spruce or fir in name, but resembling hard pine or larch in appearance, quality and uses of its wood.

40. Douglas Spruce (Pseudotsuga douglasii) (Yellow Fir, Red Fir, Oregon Pine). One of the most important trees of the western United States; grows very large in the Pacific States, to fair size in all parts of the mountains, in Colorado up to about 10,000 feet above sea level; forms extensive forests, often of pure growth, it is really neither a pine nor a fir. Wood very variable, usually coarse-grained and heavy, with very pronounced summer-wood. Hard and strong ("red" fir), but often fine-grained and light ("yellow" fir). It is the chief tree of Washington and Oregon, and most abundant and most valuable in British Columbia, where it attains its greatest size. From the plains to the Pacific Ocean, and from Mexico to British Columbia.

41. Red Fir (Pseudotsuga taxifolia) (Oregon Pine, Puget Sound Pine, Yellow Fir, Douglas Spruce, Red Pine). Heartwood light red or yellow in color, sapwood narrow, nearly white, comparatively free from resins, variable annual rings. Wood usually hard, strong, difficult to work, durable, splinters easily. Used for heavy construction, dimension timber, railway ties, doors, blinds, interior finish, piles, etc. One of the most important of Western trees. From the plains to the Pacific Ocean, and from Mexico to British America.

TAMARACK (See Larch)

YEW

Wood heavy, hard, extremely stiff and strong, of fine texture with a pale yellow sapwood, and an orange-red heartwood; seasons well and is quite durable. Extensively used for archery bows, turner's ware, etc. The yews form no forests, but occur scattered with other conifers.

42. Yew (Taxus brevifolia). A small to medium-sized tree of the Pacific region.

SECTION III

BROAD-LEAVED TREES

WOOD OF BROAD-LEAVED TREES

Fig. 4. Block of Oak. CS, cross-section; RS, radial section; TS, tangential section; mr, medullary or pith ray; a, height; b, width; and e, length of pith ray.

On a cross-section of oak, the same arrangement of pith and bark, of sapwood and heartwood, and the same disposition of the wood in well-defined concentric or annual rings occur, but the rings are marked by lines or rows of conspicuous pores or openings, which occupy the greater part of the spring-wood for each ring (see [Fig. 4], also 6), and are, in fact the hollows of vessels through which the cut has been made. On the radial section or quarter-sawn board the several layers appear as so many stripes (see [Fig. 5]); on the tangential section or "bastard" face patterns similar to those mentioned for pine wood are observed. But while the patterns in hard pine are marked by the darker summer-wood, and are composed of plain, alternating stripes of darker and lighter wood, the figures in oak (and other broad-leaved woods) are due chiefly to the vessels, those of the spring-wood in oak being the most conspicuous (see [Fig. 5]). So that in an oak table, the darker, shaded parts are the spring-wood, the lighter unicolored parts the summer-wood. On closer examination of the smooth cross-section of oak, the spring-wood part of the ring is found to be formed in great part of pores; large, round, or oval openings made by the cut through long vessels. These are separated by a grayish and quite porous tissue (see [Fig. 6], A), which continues here and there in the form of radial, often branched, patches (not the pith rays) into and through the summer-wood to the spring-wood of the next ring. The large vessels of the spring-wood, occupying six to ten per cent of the volume of a log in very good oak, and twenty-five per cent or more in inferior and narrow-ringed timber, are a very important feature, since it is evident that the greater their share in the volume, the lighter and weaker the wood. They are smallest near the pith, and grow wider outward. They are wider in the stem than limb, and seem to be of indefinite length, forming open channels, in some cases probably as long as the tree itself. Scattered through the radiating gray patches of porous wood are vessels similar to those of the spring-wood, but decidedly smaller. These vessels are usually fewer and larger near the outer portions of the ring. Their number and size can be utilized to distinguish the oaks classed as white oaks from those classed as black and red oaks. They are fewer and larger in red oaks, smaller but much more numerous in white oaks. The summer-wood, except for these radial, grayish patches, is dark colored and firm. This firm portion, divided into bodies or strands by these patches of porous wood, and also by fine, wavy, concentric lines of short, thin-walled cells (see [Fig. 6], A), consists of thin-walled fibres (see [Fig. 7], B), and is the chief element of strength in oak wood. In good white oak it forms one-half or more of the wood, if it cuts like horn, and the cut surface is shiny, and of a deep chocolate brown color. In very narrow-ringed wood and in inferior red oak it is usually much reduced in quantity as well as quality. The pith rays of the oak, unlike those of the coniferous woods, are at least in part very large and conspicuous. (See [Fig. 4]; their height indicated by the letter a, and their width by the letter b.) The large medullary rays of oak are often twenty and more cells wide, and several hundred cell rows in height, which amount commonly to one or more inches. These large rays are conspicuous on all sections. They appear as long, sharp, grayish lines on the cross-sections; as short, thick lines, tapering at each end, on the tangential or "bastard" face, and as broad, shiny bands, "the mirrors," on the radial section. In addition to these coarse rays, there is also a large number of small pith rays, which can be seen only when magnified. On the whole, the pith rays form a much larger part of the wood than might be supposed. In specimens of good white oak it has been found that they form about sixteen to twenty-five per cent of the wood.

Fig. 5. Board of Oak. CS, cross-section; RS, radial section; TS, tangential section; v, vessels or pores, cut through.; A, slight curve in log which appears in section as an islet.

Fig. 6. Cross-section of Oak (Magnified about 5 times).

Fig. 7. Portion of the Firm Bodies of Fibres with Two Cells of a Small Pith Ray mr (Highly Magnified).

Fig. 8. Isolated Fibres and Cells, a, four cells of wood, parenchyma; b, two cells from a pith ray; c, a single joint or cell of a vessel, the openings x leading into its upper and lower neighbors; d, tracheid; e, wood fibre proper.

Minute Structure

Fig. 9. Cross-section of Basswood (Magnified). v, vessels; mr, pith rays.

If a well-smoothed thin disk or cross-section of oak (say one-sixteenth inch thick) is held up to the light, it looks very much like a sieve, the pores or vessels appearing as clean-cut holes. The spring-wood and gray patches are seen to be quite porous, but the firm bodies of fibres between them are dense and opaque. Examined with a magnifier it will be noticed that there is no such regularity of arrangement in straight rows as is conspicuous in pine. On the contrary, great irregularity prevails. At the same time, while the pores are as large as pin holes, the cells of the denser wood, unlike those of pine wood, are too small to be distinguished. Studied with the microscope, each vessel is found to be a vertical row of a great number of short, wide tubes, joined end to end (see [Fig. 8], c). The porous spring-wood and radial gray tracts are partly composed of smaller vessels, but chiefly of tracheids, like those of pine, and of shorter cells, the "wood parenchyma," resembling the cells of the medullary rays. These latter, as well as the fine concentric lines mentioned as occurring in the summer-wood, are composed entirely of short tube-like parenchyma cells, with square or oblique ends (see [Fig. 8], a and b). The wood fibres proper, which form the dark, firm bodies referred to, are very fine, thread-like cells, one twenty-fifth to one-tenth inch long, with a wall commonly so thick that scarcely any empty internal space or lumen remains (see [Figs. 8], e, and [7], B). If, instead of oak, a piece of poplar or basswood (see [Fig. 9]) had been used in this study, the structure would have been found to be quite different. The same kinds of cell-elements, vessels, etc., are, to be sure, present, but their combination and arrangement are different, and thus from the great variety of possible combinations results the great variety of structure and, in consequence, of the qualities which distinguish the wood of broad-leaved trees. The sharp distinction of sap wood and heartwood is wanting; the rings are not so clearly defined; the vessels of the wood are small, very numerous, and rather evenly scattered through the wood of the annual rings, so that the distinction of the ring almost vanishes and the medullary or pith rays in poplar can be seen, without being magnified, only on the radial section.

LIST OF MOST IMPORTANT BROAD-LEAVED TREES (HARDWOODS)

Woods of complex and very variable structure, and therefore differing widely in quality, behavior, and consequently in applicability to the arts.

AILANTHUS

1. Ailanthus (Ailanthus glandulosa). Medium to large-sized tree. Wood pale yellow, hard, fine-grained, and satiny. This species originally came from China, where it is known as the Tree of "Heaven," was introduced into the United States and planted near Philadelphia during the 18th century, and is more ornamental than useful. It is used to some extent in cabinet work. Western Pennsylvania and Long Island, New York.

ASH

Wood heavy, hard, stiff, quite tough, not durable in contact with the soil, straight-grained, rough on the split surfaces and coarse in texture. The wood shrinks moderately, seasons with little injury, stands well, and takes a good polish. In carpentry, ash is used for stairways, panels, etc. It is used in shipbuilding, in the construction of cars, wagons, etc., in the manufacture of all kinds of farm implements, machinery, and especially of all kinds of furniture; for cooperage, baskets, oars, tool handles, hoops, etc., etc. The trees of the several species of ash are rapid growers, of small to medium height with stout trunks. They form no forests, but occur scattered in almost all our broad-leaved forests.

2. White Ash (Fraxinus Americana). Medium-, sometimes large-sized tree. Heartwood reddish brown, usually mottled; sapwood lighter color, nearly white. Wood heavy, hard, tough, elastic, coarse-grained, compact structure. Annual rings clearly marked by large open pores, not durable in contact with the soil, is straight-grained, and the best material for oars, etc. Used for agricultural implements, tool handles, automobile (rim boards), vehicle bodies and parts, baseball bats, interior finish, cabinet work, etc., etc. Basin of the Ohio, but found from Maine to Minnesota and Texas.

3. Red Ash (Fraxinus pubescens var. Pennsylvanica). Medium-sized tree, a timber very similar to, but smaller than Fraxinus Americana. Heartwood light brown, sapwood lighter color. Wood heavy, hard, strong, and coarse-grained. Ranges from New Brunswick to Florida, and westward to Dakota, Nebraska, and Kansas.

4. Black Ash (Fraxinus nigra var. sambucifolia) (Hoop Ash, Ground Ash). Medium-sized tree, very common, is more widely distributed than the Fraxinus Americana; the wood is not so hard, but is well suited for hoops and basketwork. Heartwood dark brown, sapwood light brown or white. Wood heavy, rather soft, tough and coarse-grained. Used for barrel hoops, basketwork, cabinetwork and interior of houses. Maine to Minnesota and southward to Alabama.

5. Blue Ash (Fraxinus quadrangulata). Small to medium-sized tree. Heartwood yellow, streaked with brown, sapwood a lighter color. Wood heavy, hard, and coarse-grained. Not common. Indiana and Illinois; occurs from Michigan to Minnesota and southward to Alabama.

6. Green Ash (Fraxinus viridis). Small-sized tree. Occurs from New York to the Rocky Mountains, and southward to Florida and Arizona.

7. Oregon Ash (Fraxinus Oregana). Small to medium-sized tree. Occurs from western Washington to California.

8. Carolina Ash (Fraxinus Caroliniana). Medium-sized tree. Occurs in the Carolinas and the coast regions southward.

ASPEN (See Poplar)

BASSWOOD

9. Basswood (Tilia Americana) (Linden, Lime Tree, American Linden, Lin, Bee Tree). Medium- to large-sized tree. Wood light, soft, stiff, but not strong, of fine texture, straight and close-grained, and white to light brown color, but not durable in contact with the soil. The wood shrinks considerably in drying, works well and stands well in interior work. It is used for cooperage, in carpentry, in the manufacture of furniture and woodenware (both turned and carved), for toys, also for panelling of car and carriage bodies, for agricultural implements, automobiles, sides and backs of drawers, cigar boxes, excelsior, refrigerators, trunks, and paper pulp. It is also largely cut for veneer and used as "three-ply" for boxes and chair seats. It is used for sounding boards in pianos and organs. If well seasoned and painted it stands fairly well for outside work. Common in all northern broad-leaved forests. Found throughout the eastern United States, but reaches its greatest size in the Valley of the Ohio, becoming often 130 feet in height, but its usual height is about 70 feet.

10. White Basswood (Tilia heterophylla) (Whitewood). A small-sized tree. Wood in its quality and uses similar to the preceding, only it is lighter in color. Most abundant in the Alleghany region.

11. White Basswood (Tilia pubescens) (Downy Linden, Small-leaved Basswood). Small-sized tree. Wood in its quality and uses similar to Tilia Americana. This is a Southern species which makes it way as far north as Long Island. Is found at its best in South Carolina.

BEECH

12. Beech (Fagus ferruginea) (Red Beech, White Beech). Medium-sized tree, common, sometimes forming forests of pure growth. Wood heavy, hard, stiff, strong, of rather coarse texture, white to light brown color, not durable in contact with the soil, and subject to the inroads of boring insects. Rather close-grained, conspicuous medullary rays, and when quarter-sawn and well smoothed is very beautiful. The wood shrinks and checks considerably in drying, works well and stands well, and takes a fine polish. Beech is comparatively free from objectionable taste, and finds a place in the manufacture of commodities which come in contact with foodstuffs, such as lard tubs, butter boxes and pails, and the beaters of ice cream freezers; for the latter the persistent hardness of the wood when subjected to attrition and abrasion, while wet gives it peculiar fitness. It is an excellent material for churns. Sugar hogsheads are made of beech, partly because it is a tasteless wood and partly because it has great strength. A large class of woodenware, including veneer plates, dishes, boxes, paddles, scoops, spoons, and beaters, which belong to the kitchen and pantry, are made of this species of wood. Beech picnic plates are made by the million, a single machine turning out 75,000 a day. The wood has a long list of miscellaneous uses and enters in a great variety of commodities. In every region where it grows in commercial quantities it is made into boxes, baskets, and crating. Beech baskets are chiefly employed in shipping fruit, berries, and vegetables. In Maine thin veneer of beech is made specially for the Sicily orange and lemon trade. This is shipped in bulk and the boxes are made abroad. Beech is also an important handle wood, although not in the same class with hickory. It is not selected because of toughness and resiliency, as hickory is, and generally goes into plane, handsaw, pail, chisel, and flatiron handles. Recent statistics show that in the production of slack cooperage staves, only two woods, red gum and pine, stood above beech in quantity, while for heading, pine alone exceeded it. It is also used in turnery, for shoe lasts, butcher blocks, ladder rounds, etc. Abroad it is very extensively used by the carpenter, millwright, and wagon maker, in turnery and wood carving. Most abundant in the Ohio and Mississippi basin, but found from Maine to Wisconsin and southward to Florida.

BIRCH

13. Cherry Birch (Betula lenta) (Black Birch, Sweet Birch, Mahogany Birch, Wintergreen Birch). Medium-sized tree, very common. Wood of beautiful reddish or yellowish brown, and much of it nicely figured, of compact structure, is straight in grain, heavy, hard, strong, takes a fine polish, and considerably used as imitation of mahogany. The wood shrinks considerably in drying, works well and stands well, but is not durable in contact with the soil. The medullary rays in birch are very fine and close and not easily seen. The sweet birch is very handsome, with satiny luster, equalling cherry, and is too costly a wood to be profitably used for ordinary purposes, but there are both high and low grades of birch, the latter consisting chiefly of sapwood and pieces too knotty for first class commodities. This cheap material swells the supply of box lumber, and a little of it is found wherever birch passes through sawmills. The frequent objections against sweet birch as box lumber and crating material are that it is hard to nail and is inclined to split. It is also used for veneer picnic plates and butter dishes, although it is not as popular for this class of commodity as are yellow and paper birch, maple and beech. The best grades are largely used for furniture and cabinet work, and also for interior finish. Maine to Michigan and to Tennessee.

14. White Birch (Betula populifolia) (Gray Birch, Old Field Birch, Aspen-leaved Birch). Small to medium-sized tree, least common of all the birches. Short-lived, twenty to thirty feet high, grows very rapidly. Heartwood light brown, sapwood lighter color. Wood light, soft, close-grained, not strong, checks badly in drying, decays quickly, not durable in contact with the soil, takes a good polish. Used for spools, shoepegs, wood pulp, and barrel hoops. Fuel, value not high, but burns with bright flame. Ranges from Nova Scotia and lower St. Lawrence River, southward, mostly in the coast region to Delaware, and westward through northern New England and New York to southern shore of Lake Ontario.

15. Yellow Birch (Betula lutea) (Gray Birch, Silver Birch). Medium- to large-sized tree, very common. Heartwood light reddish brown, sapwood nearly white, close-grained, compact structure, with a satiny luster. Wood heavy, very strong, hard, tough, susceptible of high polish, not durable when exposed. Is similar to Betula lenta, and finds a place in practically all kinds of woodenware. A large percentage of broom handles on the market are made of this species of wood, though nearly every other birch contributes something. It is used for veneer plates and dishes made for pies, butter, lard, and many other commodities. Tubs and pails are sometimes made of yellow birch provided weight is not objectionable. The wood is twice as heavy as some of the pines and cedars. Many small handles for such articles as flatirons, gimlets, augers, screw drivers, chisels, varnish and paint brushes, butcher and carving knives, etc. It is also widely used for shipping boxes, baskets, and crates, and it is one of the stiffest, strongest woods procurable, but on account of its excessive weight it is sometimes discriminated against. It is excellent for veneer boxes, and that is probably one of the most important places it fills. Citrus fruit from northern Africa and the islands and countries of the Mediterranean is often shipped to market in boxes made of yellow birch from veneer cut in New England. The better grades are also used for furniture and cabinet work, and the "burls" found on this species are highly valued for making fancy articles, gavels, etc. It is extensively used for turnery, buttons, spools, bobbins, wheel hubs, etc. Maine to Minnesota and southward to Tennessee.

16. Red Birch (Betula rubra var. nigra) (River Birch). Small to medium-sized tree, very common. Lighter and less valuable than the preceding. Heartwood light brown, sapwood pale. Wood light, fairly strong and close-grained. Red birch is best developed in the middle South, and usually grows near the banks of rivers. Its bark hangs in tatters, even worse than that of paper birch, but it is darker. In Tennessee the slack coopers have found that red birch makes excellent barrel heads and it is sometimes employed in preference to other woods. In eastern Maryland the manufacturers of peach baskets draw their supplies from this wood, and substitute it for white elm in making the hoops or bands which stiffen the top of the basket, and provide a fastening for the veneer which forms the sides. Red birch bends in a very satisfactory manner, which is an important point. This wood enters pretty generally into the manufacture of woodenware within its range, but statistics do not mention it by name. It is also used in the manufacture of veneer picnic plates, pie plates, butter dishes, washboards, small handles, kitchen and pantry utensils, and ironing boards. New England to Texas and Missouri.

17. Canoe Birch (Betula paprifera) (White Birch, Paper Birch). Small to medium-sized tree, sometimes forming forests, very common. Heartwood light brown tinged with red, sapwood lighter color. Wood of good quality, but light, fairly hard and strong, tough, close-grained. Sap flows freely in spring and by boiling can be made into syrup. Not as valuable as any of the preceding. Canoe birch is a northern tree, easily identified by its white trunk and its ragged bark. Large numbers of small wooden boxes are made by boring out blocks of this wood, shaping them in lathes, and fitting lids on them. Canoe birch is one of the best woods for this class of commodities, because it can be worked very thin, does not split readily, and is of pleasing color. Such boxes, or two-piece diminutive kegs, are used as containers for articles shipped and sold in small bulk, such as tacks, small nails, and brads. Such containers are generally cylindrical and of considerably greater depth than diameter. Many others of nearly similar form are made to contain ink bottles, bottles of perfumery, drugs, liquids, salves, lotions, and powders of many kinds. Many boxes of this pattern are used by manufacturers of pencils and crayons for packing and shipping their wares. Such boxes are made in numerous numbers by automatic machinery. A single machine of the most improved pattern will turn out 1,400 boxes an hour. After the boring and turning are done, they are smoothed by placing them into a tumbling barrel with soapstone. It is also used for one-piece shallow trays or boxes, without lids, and used as card receivers, pin receptacles, butter boxes, fruit platters, and contribution plates in churches. It is also the principal wood used for spools, bobbins, bowls, shoe lasts, pegs, and turnery, and is also much used in the furniture trade. All along the northern boundary of the United States and northward, from the Atlantic to the Pacific.

BLACK WALNUT (See Walnut)

BLUE BEECH

18. Blue Beech (Carpinus Caroliniana) (Hornbeam, Water Beech, Ironwood). Small-sized tree. Heartwood light brown, sapwood nearly white. Wood very hard, heavy, strong, very stiff, of rather fine texture, not durable in contact with the soil, shrinks and checks considerably in drying, but works well and stands well, and takes a fine polish. Used chiefly in turnery, for tool handles, etc. Abroad much used by mill- and wheelwrights. A small tree, largest in the Southwest, but found in nearly all parts of the eastern United States.

BOIS D'ARC (See Osage Orange)

BUCKEYE

Wood light, soft, not strong, often quite tough, of fine, uniform texture and creamy white color. It shrinks considerably in drying, but works well and stands well. Used for woodenware, artificial limbs, paper pulp, and locally also for building construction.

19. Ohio Buckeye (Æsculus glabra) (Horse Chestnut, Fetid Buckeye). Small-sized tree, scattered, never forming forests. Heartwood white, sapwood pale brown. Wood light, soft, not strong, often quite tough and close-grained. Alleghanies, Pennsylvania to Oklahoma.

20. Sweet Buckeye (Æsculus octandra var. flava) (Horse Chestnut). Small-sized tree, scattered, never forming forests. Wood in its quality and uses similar to the preceding. Alleghanies, Pennsylvania to Texas.

BUCKTHORNE

21. Buckthorne (Rhanmus Caroliniana) (Indian Cherry). Small-sized tree. Heartwood light brown, sapwood almost white. Wood light, hard, close-grained. Does not enter the markets to any great extent. Found along the borders of streams in rich bottom lands. Its northern limits is Long Island, where it is only a shrub; it becomes a tree only in southern Arkansas and adjoining regions.

BUTTERNUT

22. Butternut (Juglans cinerea) (White Walnut, White Mahogany, Walnut). Medium-sized tree, scattered, never forming forests. Wood very similar to black walnut, but light, quite soft, and not strong. Heartwood light gray-brown, darkening with exposure; sapwood nearly white, coarse-grained, compact structure, easily worked, and susceptible to high polish. Has similar grain to black walnut and when stained is a very good imitation. Is much used for inside work, and very durable. Used chiefly for finishing lumber, cabinet work, boat finish and fixtures, and for furniture. Butternut furniture is often sold as circassian walnut. Largest and most common in the Ohio basin. Maine to Minnesota and southward to Georgia and Alabama.

CATALPA

The catalpa is a tree which was planted about 25 years ago as a commercial speculation in Iowa, Kansas, and Nebraska. Its native habitat was along the rivers Ohio and lower Wabash, and a century ago it gained a reputation for rapid growth and durability, but did not grow in large quantities. As a railway tie, experiments have left no doubt as to its resistance to decay; it stands abrasion as well as the white oak (Quercus alba), and is superior to it in longevity. Catalpa is a tree singularly free from destructive diseases. Wood cut from the living tree is one of the most durable timbers known. In spite of its light porous structure it resists the weathering influences and the attacks of wood-destroying fungi to a remarkable degree. No fungus has yet been found which will grow in the dead timber, and for fence posts this wood has no equal, lasting longer than almost any other species of timber. The wood is rather soft and coarse in texture, the tree is of slow growth, and the brown colored heartwood, even of very young trees, forms nearly three-quarters of their volume. There is only about one-quarter inch of sapwood in a 9-inch tree.

23. Catalpa (Catalpa speciosa var. bignonioides) (Indian Bean). Medium-sized tree. Heartwood light brown, sapwood nearly white. Wood light, soft, not strong, brittle, very durable in contact with the soil, of coarse texture. Used chiefly for railway ties, telegraph poles, and fence posts, but well suited for a great variety of uses. Lower basin of the Ohio River, locally common. Extensively planted, and therefore promising to become of some importance.

CHERRY

24. Cherry (Prunus serotina) (Wild Cherry, Black Cherry, Rum Cherry). Wood heavy, hard, strong, of fine texture. Sapwood yellowish white, heartwood reddish to brown. The wood shrinks considerably in drying, works well and stands well, has a fine satin-like luster, and takes a fine polish which somewhat resembles mahogany, and is much esteemed for its beauty. Cherry is chiefly used as a decorative interior finishing lumber, for buildings, cars and boats, also for furniture and in turnery, for musical instruments, walking sticks, last blocks, and woodenware. It is becoming too costly for many purposes for which it is naturally well suited. The lumber-furnishing cherry of the United States, the wild black cherry, is a small to medium-sized tree, scattered through many of the broad-leaved trees of the western slope of the Alleghanies, but found from Michigan to Florida, and west to Texas. Other species of this genus, as well as the hawthornes (Prunus cratoegus) and wild apple (Pyrus), are not commonly offered in the markets. Their wood is of the same character as cherry, often finer, but in smaller dimensions.

25. Red Cherry (Prunus Pennsylvanica) (Wild Red Cherry, Bird Cherry). Small-sized tree. Heartwood light brown, sapwood pale yellow. Wood light, soft, and close-grained. Uses similiar to the preceding, common throughout the Northern States, reaching its greatest size on the mountains of Tennessee.

CHESTNUT

The chestnut is a long-lived tree, attaining an age of from 400 to 600 years, but trees over 100 years are usually hollow. It grows quickly, and sprouts from a chestnut stump (Coppice Chestnut) often attain a height of 8 feet in the first year. It has a fairly cylindrical stem, and often grows to a height of 100 feet and over. Coppice chestnut, that is, chestnut grown on an old stump, furnishes better timber for working than chestnut grown from the nut, it is heavier, less spongy, straighter in grain, easier to split, and stands exposure longer.

26. Chestnut (Castanea vulgaris var. Americana). Medium- to large-sized tree, never forming forests. Wood is light, moderately hard, stiff, elastic, not strong, but very durable when in contact with the soil, of coarse texture. Sapwood light, heartwood darker brown, and is readily distinguishable from the sapwood, which very early turns into heartwood. It shrinks and checks considerably in drying, works easily, stands well. The annual rings are very distinct, medullary rays very minute and not visible to the naked eye. Used in cooperage, for cabinetwork, agricultural implements, railway ties, telegraph poles, fence posts, sills, boxes, crates, coffins, furniture, fixtures, foundation for veneer, and locally in heavy construction. Very common in the Alleghanies. Occurs from Maine to Michigan and southward to Alabama.

27. Chestnut (Castanea dentata var. vesca). Medium-sized tree, never forming forests, not common. Heartwood brown color, sapwood lighter shade, coarse-grained. Wood and uses similar to the preceding. Occurs scattered along the St. Lawrence River, and even there is met with only in small quantities.

28. Chinquapin (Castanea pumila). Medium- to small-sized tree, with wood slightly heavier, but otherwise similiar to the preceding. Most common in Arkansas, but with nearly the same range as Castanea vulgaris.

29. Chinquapin (Castanea chrysophylla). A medium-sized tree of the western ranges of California and Oregon.

COFFEE TREE

30. Coffee Tree (Gymnocladus dioicus) (Coffee Nut, Stump Tree). A medium- to large-sized tree, not common. Wood heavy, hard, strong, very stiff, of coarse texture, and durable. Sapwood yellow, heartwood reddish brown, shrinks and checks considerably in drying, works well and stands well, and takes a fine polish. It is used to a limited extent in cabinetwork and interior finish. Pennsylvania to Minnesota and Arkansas.

COTTONWOOD (See Poplar)

CRAB APPLE

31. Crab Apple (Pyrus coronaria) (Wild Apple, Fragrant Crab). Small-sized tree. Heartwood reddish brown, sapwood yellow. Wood heavy, hard, not strong, close-grained. Used principally for tool handles and small domestic articles. Most abundant in the middle and western states, reaches its greatest size in the valleys of the lower Ohio basin.

CUCUMBER TREE (See Magnolia)

DOGWOOD

32. Dogwood (Cornus florida) (American Box). Small to medium-sized tree. Attains a height of about 30 feet and about 12 inches in diameter. The heartwood is a red or pinkish color, the sapwood, which is considerable, is a creamy white. The wood has a dull surface and very fine grain. It is valuable for turnery, tool handles, and mallets, and being so free from silex, watchmakers use small splinters of it for cleaning out the pivot holes of watches, and opticians for removing dust from deep-seated lenses. It is also used for butchers' skewers, and shuttle blocks and wheel stock, and is suitable for turnery and inlaid work. Occurs scattered in all the broad-leaved forests of our country; very common.

ELM

Wood heavy, hard, strong, elastic, very tough, moderately durable in contact with the soil, commonly cross-grained, difficult to split and shape, warps and checks considerably in drying, but stands well if properly seasoned. The broad sapwood whitish, heartwood light brown, both with shades of gray and red. On split surfaces rough, texture coarse to fine, capable of high polish. Elm for years has been the principal wood used in slack cooperage for barrel staves, also in the construction of cars, wagons, etc., in boat building, agricultural implements and machinery, in saddlery and harness work, and particularly in the manufacture of all kinds of furniture, where the beautiful figures, especially those of the tangential or bastard section, are just beginning to be appreciated. The elms are medium- to large-sized trees, of fairly rapid growth, with stout trunks; they form no forests of pure growth, but are found scattered in all the broad-leaved woods of our country, sometimes forming a considerable portion of the arborescent growth.

33. White Elm (Ulmus Americana) (American Elm, Water Elm). Medium- to large-sized tree. Wood in its quality and uses as stated above. Common. Maine to Minnesota, southward to Florida and Texas.

34. Rock Elm (Ulmus racemosa) (Cork Elm, Hickory Elm, White Elm, Cliff Elm). Medium- to large-sized tree of rapid growth. Heartwood light brown, often tinged with red, sapwood yellowish or greenish white, compact structure, fibres interlaced. Wood heavy, hard, very tough, strong, elastic, difficult to split, takes a fine polish. Used for agricultural implements, automobiles, crating, boxes, cooperage, tool handles, wheel stock, bridge timbers, sills, interior finish, and maul heads. Fairly free from knots and has only a small quantity of sapwood. Michigan, Ohio, from Vermont to Iowa, and southward to Kentucky.

35. Red Elm (Ulmus fulva var. pubescens) (Slippery Elm, Moose Elm). The red or slippery elm is not as large a tree as the white elm (Ulmus Americana), though it occasionally attains a height of 135 feet and a diameter of 4 feet. It grows tall and straight, and thrives in river valleys. The wood is heavy, hard, strong, tough, elastic, commonly cross-grained, moderately durable in contact with the soil, splits easily when green, works fairly well, and stands well if properly handled. Careful seasoning and handling are essential for the best results. Trees can be utilized for posts when very small. When green the wood rots very quickly in contact with the soil. Poles for posts should be cut in summer and peeled and dried before setting. The wood becomes very tough and pliable when steamed, and is of value for sleigh runners and for ribs of canoes and skiffs. Together with white elm (Ulmus Americana) it is extensively used for barrel staves in slack cooperage and also for furniture. The thick, viscous inner bark, which gives the tree its descriptive name, is quite palatable, slightly nutritious, and has a medicinal value. Found chiefly along water courses. New York to Minnesota, and southward to Florida and Texas.

36. Cedar Elm (Ulmus crassifolia). Medium- to small-sized tree, locally quite common. Arkansas and Texas.

37. Winged Elm (Ulmus alata) (Wahoo). Small-sized tree, locally quite common. Heartwood light brown, sapwood yellowish white. Wood heavy, hard, tough, strong, and close-grained. Arkansas, Missouri, and eastern Virginia.

Fig. 10. A Large Red Gum.

GUM

This general term applies to three important species of gum in the South, the principal one usually being distinguished as "red" or "sweet" gum (see [Fig. 10]). The next in importance being the "tupelo" or "bay poplar," and the least of the trio is designated as "black" or "sour" gum (see [Fig. 11]). Up to the year 1900 little was known of gum as a wood for cooperage purposes, but by the continued advance in price of the woods used, a few of the most progressive manufacturers, looking into the future, saw that the supply of the various woods in use was limited, that new woods would have to be sought, and gum was looked upon as a possible substitute, owing to its cheapness and abundant supply. No doubt in the future this wood will be used to a considerable extent in the manufacture of both "tight" and "slack" cooperage. In the manufacture of the gum, unless the knives and saws are kept very sharp, the wood has a tendency to break out, the corners splitting off; and also, much difficulty has been experienced in seasoning and kiln-drying.

Fig. 11. A Tupelo Gum Slough.

In the past, gum, having no marketable value, has been left standing after logging operations, or, where the land has been cleared for farming, the trees have been "girdled" and allowed to rot, and then felled and burned as trash. Now, however, that there is a market for this species of timber, it will be profitable to cut the gum with the other hardwoods, and this species of wood will come in for a greater share of attention than ever before.

38. Red Gum (Liquidamber styraciflua) (Sweet Gum, Hazel Pine, Satin Walnut, Liquidamber, Bilsted). The wood is about as stiff and as strong as chestnut, rather heavy, it splits easily and is quite brash, commonly cross-grained, of fine texture, and has a large proportion of whitish sapwood, which decays rapidly when exposed to the weather; but the reddish brown heartwood is quite durable, even in the ground. The external appearance of the wood is of fine grain and smooth, close texture, but when broken the lines of fracture do not run with apparent direction of the growth; possibly it is this unevenness of grain which renders the wood so difficult to dry without twisting and warping. It has little resiliency; can be easily bent when steamed, and when properly dried will hold its shape. The annual rings are not distinctly marked, medullary rays fine and numerous. The green wood contains much water, and consequently is heavy and difficult to float, but when dry it is as light as basswood. The great amount of water in the green wood, particularly in the sap, makes it difficult to season by ordinary methods without warping and twisting. It does not check badly, is tasteless and odorless, and when once seasoned, swells and shrinks but little unless exposed to the weather. Used for boat finish, veneers, cabinet work, furniture, fixtures, interior decoration, shingles, paving blocks, woodenware, cooperage, machinery frames, refrigerators, and trunk slats.

Range of Red Gum

Red gum is distributed from Fairfield County, Conn., to southeastern Missouri, through Arkansas and Oklahoma to the valley of the Trinity River in Texas, and eastward to the Atlantic coast. Its commercial range is restricted, however, to the moist lands of the lower Ohio and Mississippi basins and of the Southeastern coast. It is one of the commonest timber trees in the hardwood bottoms and drier swamps of the South. It grows in mixture with ash, cottonwood and oak (see [Fig. 12]). It is also found to a considerable extent on the lower ridges and slopes of the southern Appalachians, but there it does not reach merchantable value and is of little importance. Considerable difference is found between the growth in the upper Mississippi bottoms and that along the rivers on the Atlantic coast and on the Gulf. In the latter regions the bottoms are lower, and consequently more subject to floods and to continued overflows (see [Fig. 11]). The alluvial deposit is also greater, and the trees grow considerably faster. Trees of the same diameter show a larger percentage of sapwood there than in the upper portions of the Mississippi Valley. The Mississippi Valley hardwood trees are for the most part considerably older, and reach larger dimensions than the timber along the coast.

Form of the Red Gum

In the best situations red gum reaches a height of 150 feet, and a diameter of 5 feet. These dimensions, however are unusual. The stem is straight and cylindrical, with dark, deeply-furrowed bark, and branches often winged with corky ridges. In youth, while growing vigorously under normal conditions, it assumes a long, regular, conical crown, much resembling the form of a conifer (see [Fig. 12]). After the tree has attained its height growth, however, the crown becomes rounded, spreading and rather ovate in shape. When growing in the forest the tree prunes itself readily at an early period, and forms a good length of clear stem, but it branches strongly after making most of its height growth. The mature tree is usually forked, and the place where the forking commences determines the number of logs in the tree or its merchantable length, by preventing cutting to a small diameter in the top. On large trees the stem is often not less than eighteen inches in diameter where the branching begins. The over-mature tree is usually broken and dry topped, with a very spreading crown, in consequence of new branches being sent out.

Tolerance of Red Gum

Throughout its entire life red gum is intolerant in shade, there are practically no red seedlings under the dense forest cover of the bottom land, and while a good many may come up under the pine forest on the drier uplands, they seldom develop into large trees. As a rule seedlings appear only in clearings or in open spots in the forest. It is seldom that an over-topped tree is found, for the gum dies quickly if suppressed, and is consequently nearly always a dominant or intermediate tree. In a hardwood bottom forest the timber trees are all of nearly the same age over considerable areas, and there is little young growth to be found in the older stands. The reason for this is the intolerance of most of the swamp species. A scale of intolerance containing the important species, and beginning with the most light-demanding, would run as follows: Cottonwood, sycamore, red gum, white elm, white ash, and red maple.

Demands upon Soil and Moisture

While the red gum grows in various situations, it prefers the deep, rich soil of the hardwood bottoms, and there reaches its best development (see [Fig. 10]). It requires considerable soil moisture, though it does not grow in the wetter swamps, and does not thrive on dry pine land. Seedlings, however, are often found in large numbers on the edges of the uplands and even on the sandy pine land, but they seldom live beyond the pole stage. When they do, they form small, scrubby trees that are of little value. Where the soil is dry the tree has a long tap root. In the swamps, where the roots can obtain water easily, the development of the tap root is poor, and it is only moderate on the glade bottom lands, where there is considerable moisture throughout the year, but no standing water in the summer months.

Reproduction of Red Gum

Fig. 12. Second Growth Red Gum, Ash, Cottonwood, and Sycamore.

Red gum reproduces both by seed and by sprouts (see [Fig. 12]). It produces seed fairly abundantly every year, but about once in three years there is an extremely heavy production. The tree begins to bear seed when twenty-five to thirty years old, and seeds vigorously up to an age of one hundred and fifty years, when its productive power begins to diminish. A great part of the seed, however, is abortive. Red gum is not fastidious in regard to its germinating bed; it comes up readily on sod in old fields and meadows, on decomposing humus in the forest, or on bare clay-loam or loamy sand soil. It requires a considerable degree of light, however, and prefers a moist seed bed. The natural distribution of the seed takes place for several hundred feet from the seed trees, the dissemination depending almost entirely on the wind. A great part of the seed falls on the hardwood bottom when the land is flooded, and is either washed away or, if already in the ground and germinating, is destroyed by the long-continued overflow. After germinating, the red gum seedling demands, above everything else, abundant light for its survival and development. It is for this reason that there is very little growth of red gum, either in the unculled forest or on culled land, where, as is usually the case, a dense undergrowth of cane, briers, and rattan is present. Under the dense underbrush of cane and briers throughout much of the virgin forest, reproduction of any of the merchantable species is of course impossible. And even where the land has been logged over, the forest is seldom open enough to allow reproduction of cottonwood and red gum. Where, however, seed trees are contiguous to pastures or cleared land, scattered seedlings are found springing up in the open, and where openings occur in the forest, there are often large numbers of red gum seedlings, the reproduction generally occurring in groups. But over the greater part of the Southern hardwood bottom land forest reproduction is very poor. The growth of red gum during the early part of its life, and up to the time it reaches a diameter of eight inches breast-high, is extremely rapid, and, like most of the intolerant species, it attains its height growth at an early period. Gum sprouts readily from the stump, and the sprouts surpass the seedlings in rate of height growth for the first few years, but they seldom form large timber trees. Those over fifty years of age seldom sprout. For this reason sprout reproduction is of little importance in the forest. The principal requirements of red gum, then, are a moist, fairly rich soil and good exposure to light. Without these it will not reach its best development.

Fig. 13. A Cypress Slough in the Dry Season.

Second-Growth Red Gum

Second-growth red gum occurs to any considerable extent only on land which has been thoroughly cleared. Throughout the South there is a great deal of land which was in cultivation before the Civil War, but which during the subsequent period of industrial depression was abandoned and allowed to revert to forest. These old fields now mostly covered with second-growth forest, of which red gum forms an important part (see [Fig. 12]). Frequently over fifty per cent of the stand consists of this species, but more often, and especially on the Atlantic coast, the greater part is of cottonwood or ash. These stands are very dense, and the growth is extremely rapid. Small stands of young growth are also often found along the edges of cultivated fields. In the Mississippi Valley the abandoned fields on which young stands have sprung up are for the most part being rapidly cleared again. The second growth here is considered of little value in comparison with the value of the land for agricultural purposes. In many cases, however, the farm value of the land is not at present sufficient to make it profitable to clear it, unless the timber cut will at least pay for the operation. There is considerable land upon which the second growth will become valuable timber within a few years. Such land should not be cleared until it is possible to utilize the timber.

39. Tupelo Gum (Nyssa aquatica) (Bay Poplar, Swamp Poplar, Cotton Gum, Hazel Pine, Circassian Walnut, Pepperidge, Nyssa). The close similarity which exists between red and tupelo gum, together with the fact that tupelo is often cut along with red gum, and marketed with the sapwood of the latter, makes it not out of place to give consideration to this timber. The wood has a fine, uniform texture, is moderately hard and strong, is stiff, not elastic, very tough and hard to split, but easy to work with tools. Tupelo takes glue, paint, or varnish well, and absorbs very little of the material. In this respect it is equal to yellow poplar and superior to cottonwood. The wood is not durable in contact with ground, and requires much care in seasoning. The distinction between the heartwood and sapwood of this species is marked. The former varies in color from a dull gray to a dull brown; the latter is whitish or light yellow like that of poplar. The wood is of medium weight, about thirty-two pounds per cubic foot when dry, or nearly that of red gum and loblolly pine. After seasoning it is difficult to distinguish the better grades of sapwood from poplar. Owing to the prejudice against tupelo gum, it was until recently marketed under such names as bay poplar, swamp poplar, nyssa, cotton gum, circassian walnut, and hazel pine. Since it has become evident that the properties of the wood fit it for many uses, the demand for tupelo has largely increased, and it is now taking rank with other standard woods under its rightful name. Heretofore the quality and usefulness of this wood were greatly underestimated, and the difficulty of handling it was magnified. Poor success in seasoning and kiln-drying was laid to defects of the wood itself, when, as a matter of fact, the failures were largely due to the absence of proper methods in handling. The passing of this prejudice against tupelo is due to a better understanding of the characteristics and uses of the wood. Handled in the way in which its particular character demands, tupelo is a wood of much value.

Uses of Tupelo Gum

Tupelo gum is now used in slack cooperage, principally for heading. It is used extensively for house flooring and inside finishing, such as mouldings, door jambs, and casings. A great deal is now shipped to European countries, where it is highly valued for different classes of manufacture. Much of the wood is used in the manufacture of boxes, since it works well upon rotary veneer machines. There is also an increasing demand for tupelo for laths, wooden pumps, violin and organ sounding boards, coffins, mantelwork, conduits and novelties. It is also used in the furniture trade for backing, drawers, and panels.

Range of Tupelo Gum

Tupelo occurs throughout the coastal region of the Atlantic States, from southern Virginia to northern Florida, through the Gulf States to the valley of the Nueces River in Texas, through Arkansas and southern Missouri to western Kentucky and Tennessee, and to the valley of the lower Wabash River. Tupelo is being extensively milled at present only in the region adjacent to Mobile Ala., and in southern and central Louisiana, where it occurs in large merchantable quantities, attaining its best development in the former locality. The country in this locality is very swampy (see [Fig. 11]), and within a radius of one hundred miles tupelo gum is one of the principal timber trees. It grows only in the swamps and wetter situations (see [Fig. 11]), often in mixture with cypress, and in the rainy season it stands in from two to twenty feet of water.

40. Black Gum (Nyssa sylvatica) (Sour Gum). Black gum is not cut to much extent, owing to its less abundant supply and poorer quality, but is used for repair work on wagons, for boxes, crates, wagon hubs, rollers, bowls, woodenware, and for cattle yokes and other purposes which require a strong, non-splitting wood. Heartwood is light brown in color, often nearly white; sapwood hardly distinguishable, fine grain, fibres interwoven. Wood is heavy, not hard, difficult to work, strong, very tough, checks and warps considerably in drying, not durable. It is distributed from Maine to southern Ontario, through central Michigan to southeastern Missouri, southward to the valley of the Brazos River in Texas, and eastward to the Kissimmee River and Tampa Bay in Florida. It is found in the swamps and hardwood bottoms, but is more abundant and of better size on the slightly higher ridges and hummocks in these swamps, and on the mountain slopes in the southern Alleghany region. Though its range is greater than that of either red or tupelo gum, it nowhere forms an important part of the forest.

HACKBERRY

41. Hackberry (Celtis occidentalis) (Sugar Berry, Nettle Tree). The wood is handsome, heavy, hard, strong, quite tough, of moderately fine texture, and greenish or yellowish color, shrinks moderately, works well and stands well, and takes a good polish. Used to some extent in cooperage, and in the manufacture of cheap furniture. Medium- to large-sized tree, locally quite common, largest in the lower Mississippi Valley. Occurs in nearly all parts of the eastern United States.

HICKORY

The hickories of commerce are exclusively North American and some of them are large and beautiful trees of 60 to 70 feet or more in height. They are closely allied to the walnut, and the wood is very like walnut in grain and color, though of a somewhat darker brown. It is one of the finest of American hardwoods in point of strength; in toughness it is superior to ash, rather coarse in texture, smooth and of straight grain, very heavy and strong as well as elastic and tenacious, but decays rapidly, especially the sapwood when exposed to damp and moisture, and is very liable to attack from worms and boring insects. The cross-section of hickory is peculiar, the annual rings appear like fine lines instead of like the usual pores, and the medullary rays, which are also very fine but distinct, in crossing these form a peculiar web-like pattern which is one of the characteristic differences between hickory and ash. Hickory is rarely subjected to artificial treatment, but there is this curious fact in connection with the wood, that, contrary to most other woods, creosote is only with difficulty injected into the sap, although there is no difficulty in getting it into the heartwood. It dries slowly, shrinks and checks considerably in seasoning; is not durable in contact with the soil or if exposed. Hickory excels as wagon and carriage stock, for hoops in cooperage, and is extensively used in the manufacture of implements and machinery, for tool handles, timber pins, harness work, dowel pins, golf clubs, and fishing rods. The hickories are tall trees with slender stems, never forming forests, occasionally small groves, but usually occur scattered among other broad-leaved trees in suitable localities. The following species all contribute more or less to the hickory of the markets:

42. Shagbark Hickory (Hicoria ovata) (Shellbark Hickory, Scalybark Hickory). A medium- to large-sized tree, quite common; the favorite among the hickories. Heartwood light brown, sapwood ivory or cream-colored. Wood close-grained, compact structure, annual rings clearly marked. Very hard, heavy, strong, tough, and flexible, but not durable in contact with the soil or when exposed. Used for agricultural implements, wheel runners, tool handles, vehicle parts, baskets, dowel pins, harness work, golf clubs, fishing rods, etc. Best developed in the Ohio and Mississippi basins; from Lake Ontario to Texas, Minnesota to Florida.

43. Mockernut Hickory (Hicoria alba) (Black Nut Hickory, Black Hickory, Bull Nut Hickory, Big Bud Hickory, White Heart Hickory). A medium- to large-sized tree. Wood in its quality and uses similar to the preceding. Its range is the same as that of Hicoria ovata. Common, especially in the South.

44. Pignut Hickory (Hicoria glabra) (Brown Hickory, Black Hickory, Switchbud Hickory). A medium- to large-sized tree. Heavier and stronger than any of the preceding. Heartwood light to dark brown, sapwood nearly white. Abundant, all eastern United States.

45. Bitternut Hickory (Hicoria minima) (Swamp Hickory). A medium-sized tree, favoring wet localities. Heartwood light brown, sapwood lighter color. Wood in its quality and uses not so valuable as Hicoria ovata, but is used for the same purposes. Abundant, all eastern United States.

46. Pecan (Hicoria pecan) (Illinois Nut). A large tree, very common in the fertile bottoms of the western streams. Indiana to Nebraska and southward to Louisiana and Texas.

HOLLY

47. Holly (Ilex opaca). Small to medium-sized tree. Wood of medium weight, hard, strong, tough, of exceedingly fine grain, closer in texture than most woods, of white color, sometimes almost as white as ivory; requires great care in its treatment to preserve the whiteness of the wood. It does not readily absorb foreign matter. Much used by turners and for all parts of musical instruments, for handles on whips and fancy articles, draught-boards, engraving blocks, cabinet work, etc. The wood is often dyed black and sold as ebony; works well and stands well. Most abundant in the lower Mississippi Valley and Gulf States, but occurring eastward to Massachusetts and north to Indiana.

48. Holly (Ilex monticolo) (Mountain Holly). Small-sized tree. Wood in its quality and uses similar to the preceding, but is not very generally known. It is found in the Catskill Mountains and extends southward along the Alleghanies as far as Alabama.

HORSE CHESTNUT (See Buckeye)

IRONWOOD

49. Ironwood (Ostrya Virginiana) (Hop Hornbeam, Lever Wood). Small-sized tree, common. Heartwood light brown tinged with red, sapwood nearly white. Wood heavy, tough, exceedingly close-grained, very strong and hard, durable in contact with the soil, and will take a fine polish. Used for small articles like levers, handles of tools, mallets, etc. Ranges throughout the United States east of the Rocky Mountains.

LAUREL