Part 2

Wood warps in the process of drying unless it seasons equally on all sides. It curls or bends toward the side which dries most rapidly. Dry wood may warp if exposed to dampness, if one side is more exposed and receives more moisture than another. It curls or bends toward the dryer side.

Warping is primarily due to the more rapid contraction or expansion of wood cells on one side of the piece than on the other. Saturated cells are larger than dry ones.

Moisture in wood affects its strength, the dryer the stronger, at least within certain limits. Architects and builders carefully study the seasoning of timber, because it is a most important factor in their business. The moisture which most affects a wood’s strength is that absorbed in the cell walls, rather than that contained in the cell cavities themselves.

Some woods check or split badly in seasoning unless attended with constant care. Checking is due chiefly to lack of uniformity in seasoning. One part of the stick dries faster than another, the dryer fibers contract, and the pull splits the wood. The checks may be small, even microscopic, or they may develop yawning cracks such as sometimes appear in the ends of hickory and black walnut logs. Greenwood checks worse in summer than in winter, because the weather is warmer, the wood’s surface dries faster, and the strain on the fibers is greater. Phases of the moon have no influence on the seasoning, checking, warping, or lasting properties of timber.

_Stiffness, Elasticity, and Strength_--Rules for measuring the stiffness of timber are involved in mathematical formulas; but the practical quality of stiffness is not difficult to understand. Wood which does not bend easily is stiff. If it springs back to its original position after the removal of the force which bends it, the wood is elastic. The greatest load it can sustain without breaking, is the measure of its strength. The load required to produce a certain amount of bending is the measure of its stiffness. Flexibility, a term much used by certain classes of workers in wood, is the opposite of stiffness. A brittle wood is not necessarily weak. It may sustain a heavy load without breaking, but when it fails, the break is sudden and complete. A tough wood behaves differently, though it may not be as strong as a brittle one. When a tough wood breaks, the parts are inclined to adhere after they have ceased to sustain the load. Hickory is tough, and in breaking, the wood crushes and splinters. Mesquite is brittle, and a clean snap severs the stick at once.

Builders of houses and bridges, and the manufacturers of articles of wood, study with the greatest care the stiffness, elasticity, strength, toughness, and brittleness of timber. Its chief value may depend upon the presence or absence of one or more of these properties. Take away hickory’s toughness and elasticity and it would cease to be a great vehicle and handle material. Reduce the stiffness and strength of longleaf pine and Douglas fir and they would drop at once from the high esteem in which they are held as structural timbers. Destroy the brittleness of red cedar and it would lose one of the chief qualities which make it the leading lead pencil wood of the world.

There are recognized methods of measuring these important physical properties of woods, but they are expressed in language so technical that it means little to persons who are not specialists. For ordinary purposes, it is unnecessary to be more explicit than to state a certain wood is or is not strong, stiff, tough and elastic. Some species possess one or more of these properties to double the degree that others possess them. Different trees of the same species differ greatly, and even different parts of the same tree. Most tables of figures which show the various physical properties of woods, give averages only, not absolute values.

_Hardness_--In some woods hardness is considered an advantage, but not in others. If sugar maple were as soft as white pine, it would not be the great floor material it is; and if white pine were as hard as maple, pattern makers would not want it, door and sash manufacturers would get along with less, and it would not be the leading packing box material in so wide a region.

It is generally the summer growth in the annual rings which makes a wood hard. The summerwood is dense. A given bulk of it contains more actual wood substance and less air and water than the springwood. For the same reason, summerwood gives weight, and a relationship between hardness and weight holds generally. It may be added that strength goes with weight and hardness, but it is not a rule without apparent exceptions.

Some woods possess twice or three times the hardness of others. Among some of the hardest in the United States are hickory, sugar maple, mesquite, the Florida ironwoods, Osage orange, locust, persimmon, and the best oak and elm. Among the softest species are buckeye, basswood, cedar, redwood, some of the pines, spruce, hemlock, and chestnut.

The hardness of wood is tested with a machine which records the pressure required to indent the surface. The condition of the specimen, as to dryness, has much to do with its hardness. So many other factors exercise influence that nothing less than an actual test will determine the hardness of a sample. A table of figures can show it only approximately and by averages.

_Cleavability_--Wood users generally demand a material which does not split easily, but the reverse is sometimes required. Rived staves must come from timbers which split easily. Many handles are from billets which are split in rough form and are afterwards dressed to the required size and shape. In these instances, splitting is preferable to sawing, because a rived billet is free from cross grain.

The cleavability of woods differs greatly. Some can scarcely be split. Black gum is in that list, and sycamore to a less extent. Young trees of some species split more readily than old, while with others, the advantage is with the old. Young sycamore may generally be split with ease, but old trunks seem to develop interlocked fibers which defy the wedge. A white oak pole is hard to split, but the old tree yields readily. Few woods are more easily split than chestnut. With most timbers cleavage is easiest along the radial lines, that is, from the heart to the bark. The flat sides of the medullary rays lie in that plane. Cleavage along tangential lines is easy with some woods. The line of cleavage follows the soft springwood. Green timber is generally, but not always, more easily split than dry. As a rule, the more elastic a wood is, the more readily it may be split.

_Durability_--In Egypt where climatic conditions are highly favorable, Lebanon cedar, North African acacia, East African persimmon, and oriental sycamore have remained sound during three or four thousand years. In the moist forests of the northwestern Pacific coast, an alder log six or eight inches in diameter will decay through and through in a single year. No wood is immune to decay if exposed to influences which induce it, but some resist for long periods. Osage orange and locust fence posts may stand half a century. Timber from which air is excluded, as when deeply buried in wet earth or under water, will last indefinitely; but if it is exposed to alternate dampness and dryness, decay will destroy it in a few years.

It is apparent that resistance to decay is not a property inherent in the wood, but depends on circumstances. However, the ability to resist decay varies greatly with different species, under similar circumstances. Buckeye and red cedar fence posts, situated alike, will not last alike. The buckeye may be expected to fall in two or three years, and the cedar will stand twenty. Timbers light in weight and light in color are, as a class, quick-decaying when exposed to the weather.

The rule holds in most cases that sapwood decays more quickly than heart when both are subject to similar exposure. The matter of decay is not important when lumber and other products intended for use are in dry situations. Furniture and interior house finish do not decay under ordinary circumstances, no matter what the species of wood may be; but resistance to decay overshadows almost any other consideration in choosing mine timbers, crossties, fence posts, and tanks and silos.

Decay in timber is not simply a chemical process, but is due primarily to the activities of a low order of plants known as fungi, sometimes bacteria. The fungi produce thread-like filaments which penetrate the body of the wood, ramifying in and passing from cell to cell, absorbing certain materials therein, and ultimately breaking down and destroying the structure of the wood. Both air and dampness are essential to the growth of fungus. That is the reason why timbers deep beneath ground or water do not decay. Air is absent, though moisture is abundant; while in the dry Egyptian tombs, air is abundant but moisture is wanting, fungus cannot exist, and consequently decay of the wood does not occur. Nothing is needed to render timber immune to decay except to keep fungus out of the cells. Some of the fungus concerned in wood rotting is microscopic, while other appears in forms and sizes easily seen and recognized.

Timber may be protected for a time against the agencies of decay by covering the surface with paint, thereby preventing the entrance of fungus. By another process, certain oils or other materials which are poisonous to the insinuating threads of fungus, are forced into the pores of the wood. Creosote is often used for this purpose. Attacks are thus warded off, and decay is hindered. The preservative fluid will not remain permanently in wood exposed to weather conditions, but the period during which it affords protection and immunity extends over some years; but different woods vary greatly in their ability to receive and retain preservative mixtures.

The better seasoned, the less liable is timber to decay, because it contains less moisture to support fungi. It is generally supposed that timber cut in the fall of the year is less subject to decay than if felled in summer. If it is so, the reason for it lies in the fact that fungus is inactive during winter, and before the coming of warm weather the timber has partly dried near the surface, and fungi cannot pass through the dry outside to reach the interior. Timber cut in warm weather may be attacked at once, and before cold weather stops the

## activities of fungus it has reached the interior of the wood and the

process of rotting is under way. When the agents of decay have begun to grow in the wood, destruction will go on as long as air and moisture conditions are favorable.

The bluing of wood is an incipient decay and is generally due to fungus. Some kinds of wood are more susceptible to bluing than others. Though boards may quickly season sufficiently to put a stop to the bluing process before it has actually weakened the material, the result is more or less injurious. The wood’s natural color and luster undergo deterioration; it does not reflect light as formerly, and seems dead and flat.

Decay affects sapwood more readily than heart. The reason may be that sapwood contains more food for fungus, thereby inducing greater

## activity. The sapwood is on the outside of timbers and is often more

exposed than the heart. In some instances greater decay may be due to greater exposure. Another reason for more rapid decay of sapwood than heart is the fact that the pores of the heartwood are more or less filled with coloring matter deposited while the growth of the tree was in progress. The coloring matter, in many cases, acts as a preservative; it shuts the threads of fungus out. Sometimes the sapwood of a dead tree or a log is totally destroyed while the heart remains sound. This often happens with red cedar and sometimes with black walnut, yellow poplar, and cherry. Occasionally a tree’s bark is more resistant to decay than its wood. Paper birch and yellow birch logs in damp situations occasionally show this. What appears to be a solid fallen trunk, proves to be nothing more than a shell of bark with a soft, pulpy mass of decayed wood within.

WHITE PINE

[Illustration: WHITE PINE]

WHITE PINE[1]

(_Pinus Strobus_)

[1] The following 12 species are usually classed soft pines: White Pine (_Pinus strobus_); Sugar Pine (_Pinus lambertiana_); Western White Pine (_Pinus monticola_); Mexican White Pine (_Pinus strobiformis_); Limber Pine (_Pinus flexilis_); Whitebark Pine (_Pinus albicaulis_); Foxtail Pine (_Pinus balfouriana_); Parry Pine (_Pinus quadrifolia_); Mexican Pinon (_Pinus cembroides_); Pinon (_Pinus edulis_); Singleleaf Pinon (_Pinus monophylla_); Bristlecone Pine (_Pinus aristata_).

The best known wood of the United States has never been burdened with a multitude of names, as many minor species have. It is commonly known as white pine in every region where it grows, and in many where the living tree is never seen, except when planted for ornament. The light color of the wood suggests the name. The bark and the foliage are of somber hue, though not as dark as hemlock and many of the pines. The name Weymouth pine is occasionally heard, but it is more used in books than by lumbermen. It is commonly supposed that the name refers to Lord Weymouth who interested himself in the tree at an early period, but this has been disputed. In Pennsylvania it is occasionally called soft pine to distinguish it from the harder and inferior pitch pine and table mountain pine with which it is sometimes associated. It is the softest of the pines, and the name is not inappropriate. In some regions of the South, where it is well known, it is called northern spruce pine in recognition of the fact that it is a northern species which has followed the Appalachian mountain ranges some hundreds of miles southward. There is no good reason for this name when applied to white pine. It should be remembered, however, that no less than a dozen tree species in the United States are sometimes called spruce pine. Cork pine is a trade name applied more frequently to the wood than to the living tree. It is the wood of old, mature, first class trunks, as nearly perfect as can be found. Pumpkin pine is another name given to the same class of wood. It is so named because the grain is homogeneous, like a pumpkin, and may be readily cut and carved in any direction. It is the ideal wood for the pattern maker, but it is now hard to get because the venerable white pines, many hundred years old, are practically gone.

The northern limit of the range of white pine stretches from Newfoundland to Manitoba, more than 1800 miles east and west across the Dominion of Canada, and southward to northern Georgia, 1200 miles in a north and south direction. But white pine does not grow in all parts of the territory thus delimited. It attained magnificent development in certain large regions before lumbering began, and in others it was scarce or totally wanting. Its ability to maintain itself on land too thin for vigorous hardwood growth gave it a monopoly of enormous stretches of sandy country, particularly in the Lake States. It occupied large areas in New England and southern Canada; developed splendid stands in New York and Pennsylvania; and it covered certain mountains and uplands southward along the mountain ranges across Maryland, West Virginia, and the elevated regions two or three hundred miles farther south.

A dozen or more varieties of white pine have been developed under cultivation, but they interest the nurseryman, not the lumberman. In all the wide extension of its range, and during all past time, nature was never able to develop a single variety of white pine which departed from the typical species. For that reason it is one of the most interesting objects of study in the tree kingdom. True, the white pine in the southern mountains differs slightly from the northern tree, but botanically it is the same. Its wood is a little heavier, its branches are more resinous and consequently adhere a longer time to the trunk after they die, resulting in lumber with more knots. The southern wood is more tinged with red, the knots are redder and usually sounder than in the North.

It is unfortunately necessary in speaking of white pine forests to use the past tense, for most of the primeval stands have disappeared. The range is as extensive as ever, because wherever a forest once grew, a few trees remain; but the merchantable timber has been cut in most regions. The tree bears winged seeds which quickly scatter over vacant spaces, and new growth would long ago, in most cases, have taken the place of the old, had not fires persistently destroyed the seedlings. In parts of New England where fire protection is afforded, dense stands of white pine are coming on, and in numerous instances profitable lumber operations are carried on in second growth forests. That condition does not exist generally in white pine regions. Primeval stands were seldom absolutely pure, but sometimes, in bodies of thousands of acres, there was little but white pine. Generally hardwoods or other softwoods grew with the pine. At its best, it is the largest pine of the United States, except the sugar pine of California. The largest trees grew in New England where diameters of six or more feet and heights exceeding 200 feet were found. A diameter of four and five feet and a height of 150 feet are about the size limits in the Lake States and the southern mountains. Trees two or three feet through and ninety and 120 tall are a fair average for mature timber.

The wood of white pine is among the lightest of the commercial timbers of this country, and among the softest. While it is not strong, it compares favorably, weight for weight, with most others. It is of rather rapid growth, and the rings of annual increase are clearly defined, and they contain comparatively few resin ducts. For that reason it may be classed as a close, compact wood. It polishes well, may be cut with great ease, and after it is seasoned it holds its form better than most woods. That property fits it admirably for doors and sash and for backing of veneer, where a little warping or twisting would do much harm.

The medullary rays are numerous but are too small to be easily seen separately, and do not figure much in the appearance of the wood. The resin passages are few and small, but the wood contains enough resin to give it a characteristic odor, which is not usually considered injurious to merchandise shipped in pine boxes. The white color of the wood gives it much of its value. Though rather weak, white pine is stiff, rather low in elasticity, is practically wanting in toughness, has little figure, and when exposed to alternate dryness and dampness it is rated poor in lasting properties; yet shingles and weather boarding of this wood have been known to stand half a century. The sapwood is lighter in color than the heart, and decays more quickly.

As long as white pine was abundant it surpassed all other woods of this country in the amount used. It was one of the earliest exports from New England, and it went to the West Indies and to Europe. England attempted to control the cutting and export of white pine, but was unsuccessful. At an early period the rivers were utilized for transporting the logs and the lumber to market, and that method has continued until the present time. Spectacular log drives were common in early times in New England, later in New York and Pennsylvania, and still later in Michigan and the other Lake States. Many billions of feet of faultless logs have gone down flooded rivers. The scenes in the woods and the life in lumber camps have been written in novels and romances, and the central figure of it all was white pine.

There are a few things for which this wood is not suitable; otherwise its use has been nearly universal in some parts of this country. It went into masts and matches, which are the largest and smallest commodities, and into almost every shape and size of product between. Most of the early houses and barns in the pine region were built of it. Hewed pine was the foundation, and the shingles were of split and shaved pine. It formed floors, doors, sash, and shutters. It was the ceiling within and the weather boarding without. It fenced the fields and bridged the streams. It went to market as rough lumber, and planing mills turned it out as dressed stock in various forms. It has probably been more extensively employed by box makers than any other wood, and though it is scarcer than formerly, hundreds of millions of feet of it are still used annually by box makers. Scores of millions of feet yearly are demanded by the manufacturers of window shade rollers, though individually the roller is a very small commodity. In this, as for patterns and many other things, no satisfactory substitute for white pine has been found.

As a timber tree, it will not disappear from this country, though the days of its greatest importance are past. Enormous tracts where it once grew will apparently never again produce a white pine sawlog. The prospect is more encouraging in other regions, and there will always be a considerable quantity of this lumber in the American market, though the high percentage of good grades which prevailed in the past will not continue in the future.

White pine belongs in the five needle group, that is, five leaves grow in a bundle. They turn yellow and fall in the autumn of the second year. The cones are slender, are from five to eleven inches in length, and ripen and disperse their seeds in the autumn of the second year.

[Illustration]

WESTERN WHITE PINE

[Illustration: WESTERN WHITE PINE]

WESTERN WHITE PINE

(_Pinus Monticola_)

The silvery luster of the needles of this tree gives it the name silver pine, by which many people know it. It appears in literature as mountain Weymouth pine, the reference being to the eastern white pine (_Pinus strobus_), which is sometimes called Weymouth pine. Finger-cone pine is a California name; so are mountain pine and soft pine. In the same state it is called little sugar pine, to distinguish it from sugar pine (_Pinus lambertiana_), which it resembles in some particulars but not in all. It is thus seen that California is generous in bestowing names on this tree, notwithstanding it is not abundant in any part of that state and is unknown in most parts.

The botanical name means “mountain pine,” and that describes the species. It does best among the mountains, and it ranges from an altitude of from 4,000 feet to 10,000 on the Sierra Nevada mountains. Sometimes trees of very large size are found near the upper limits of its range, but the best stands are in valleys and on slopes at lower altitudes. Its range lies in British Columbia, Montana, Idaho, Washington, Oregon, and California. In the latter state it follows the Sierra Nevada mountains southward to the San Joaquin river.