Sapwood

“ 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 ”

“ More than 20 such rings may be counted in the sapwood of a log such as we have mentioned, and more than 30 in the heartwood. The pithless centre is usually out of the axis. The medullary rays are not visible to the naked eye, but may be seen by a lens to be very numerous and equidistant. The pores of the heartwood may be distinguished as containing a brownish resin, while those of the outermost layer of sapwood are empty. ”

“ The wood of mature trees is reddish-brown; but young and middle aged trunks are all sapwood, and are white from bark to center. When sapwood is exposed to the air a considerable time it changes color and becomes very dark brown. The medullary rays of this oak are broad, fairly numerous, and are darker than the surrounding wood. When the log is quarter-sawed, the exposed flecks of bright surface are the darkest parts. ”

“ Sapwood is comparatively new wood. There is a time in the early history of every tree when its wood is all sapwood. Its principal functions are to conduct water from the roots to the leaves and to store up and give back according to the season the food prepared in the leaves. The more leaves a tree bears and the more thrifty its growth, the larger the volume of sapwood required, hence trees making rapid growth in the open have thicker sapwood for their size than trees of the same species growing in dense forests. ”

“ 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 ”

“ Some, species begin to form heartwood very early in life, while in others the change comes slowly. Thin sapwood is characteristic of such trees as chestnut, black locust, mulberry, Osage orange, and sassafras, while in maple, ash, gum, hickory, hackberry, beech, and loblolly pine, thick sapwood is the rule. ”

“ 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. ”

“ The sap in the tree descends through the bark, and except in early spring is not present in the wood of the tree except in the medullary rays and living tissues in the "sapwood."
What flows through the "sapwood" is chiefly water brought from the soil. It is not pure water, but contains many substances in solution, such as mineral salts, and in certain species—maple, birch, etc., it also contains at certain times a small percentage of sugar and other organic matter. ”

“ In general appearance the wood resembles white ash, but it is usually considered stronger and more springy. The trunks of young trees are largely or entirely sapwood. Sometimes no heartwood is formed until an age of [418] seventy or eighty years is reached. Many manufacturers of ash tool handles prefer this species to any other ash, because of its thick, white sapwood. It is often made into handles for hoes, rakes, shovels, pitchforks, spades, and snaths for scythes. Makers of vehicles draw liberally upon this wood within its range, as do furniture makers and the manufacturers of flooring. ”

“ The unaided eye seldom notices them. The sapwood is white in all species of hickory, and is usually very thick. The heartwood is reddish. Common opinion has long held that sapwood is tougher and more elastic than heartwood, and therefore to be preferred for most purposes. Tests made a few years ago by the United States Forest Service ran counter to the long-established opinion of users, by showing that in most respects the redwood of the heart was as good as the white sapwood. However, where resiliency is the chief requisite, as in slender handles, many manufacturers still prefer sapwood. ”

“ The heartwood is distinctly red, and the sapwood white, this color combination making very striking effects when finished for cedar chests, closets, and interior woodwork. The wood is aromatic, soft, strong, and of even texture, and these qualities make it most desirable for lead pencils. It is very durable in contact with the soil, and on that account is in great demand for posts, poles and rustic work. ”

“ Subsequent growth of wood may completely conceal the stubs which, however, will remain as knots. No matter how smooth and clear a log is on the outside, it is more or less knotty near the middle. Consequently the sapwood of an old tree, and particularly of a forest-grown tree, will be freer from knots than the heartwood. Since in most uses of wood, knots are defects that weaken the timber and interfere with its ease of working and other properties, it follows that sapwood, because of its position in the tree, may have certain advantages over heartwood. ”

“ In fact, in the case of large and old hickory trees, the sapwood nearest the bark is comparatively weak, and the best wood is in the heart, though in young trees of thrifty growth the best wood is in the sap."23 The results of tests from selected pieces lying side by side in the same tree, and also the average values for heartwood and sapwood in shipments of the commercial hickories without selection, show conclusively that "the transformation of sapwood into heartwood does not affect either the strength or toughness of the wood.... ”

“ Wood light, soft, not strong, close-grained, difficult to split, light brown or often nearly white, with thick sapwood sometimes composed of more than 100 layers of annual growth; used in the manufacture of wooden-ware, broom-handles, and wooden shoes, and largely for fruit and vegetable boxes. The wood of the roots is sometimes employed instead of cork for the floats of nets. ”

“ The wood is easily worked, satiny, susceptible of a beautiful polish, and possesses an agreeable resinous odor. The heartwood is bright, clear yellow, and the thin sapwood is a little lighter in color. In common with all other cedars, yellow cedar resists decay many years. Logs which have lain in damp woods half a century remain sound inside the sapwood. Sometimes fallen timber in that region is quickly buried under deep beds of moss which preserves it from decay much longer than if the logs lie exposed to alternate dampness and dryness. ”

“ It is of looser texture than the heartwood and floats on water, whereas the latter sinks. Both sapwood and heartwood owe their tenacity to an extremely peculiar zigzag arrangement [408] of the woody bundles. The sapwood is tasteless. The heartwood has a faintly aromatic and slightly irritating taste, and when heated or rubbed emits a weak agreeable odour.
The bark which was formerly officinal but is now almost obsolete, is very rich in oxalate of calcium and affords upon incineration not less than 23 per cent. ”

“ The rays are visible, not all continuous, some broader than others, evenly spaced with room for the pores between, showing in radial section as brown bands, so conspicuous on the sapwood as to colour it. In vertical section the pores are light coloured in the heartwood and dark in the sapwood, in which the resinous pore contents darken the wood in rings, showing as lines in the vertical section. The wood is tough and hard and not easy to work, though it has a slight sheen and takes a polish. The weight is 55 lbs. ”

“ One can tell the age of a tree by counting the number of annual rings. Sometimes, because of the interruption of normal growth, two false rings may be produced instead of a single true ring. However, such blemishes are easy for the trained eye to recognize. Heartwood does not occur in all varieties of trees. In some cases, where both heartwood and sapwood appear, it is difficult to distinguish between them as their colors are so nearly alike. Because it takes up so much moisture and plant food, sapwood rots much more quickly than heartwood. ”

“ Both the fibers and the cells of the sapwood are filled with water or sap, which may be removed by seasoning, but the sapwood of most trees used for building purposes is not as good lumber as the heartwood, as it is always susceptible to moisture. ”

“ Sometimes the folds of bark within the creases almost reach the center of the tree. The sapwood is thin, the heartwood irregular in color. Some is darker than the heartwood of southern red cedar, other is clouded and mottled, pale yellow, cream-colored, the shade of slate, or streaked with various tints. The wood can be economically worked only as small pieces. It takes a soft and pleasing finish. It is a lathe wood and shows to best advantage as balusters, ornaments, grill spindles and small posts, Indian clubs, dumb-bells, balls, and lodge gavels. ”

“ 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 sapwood is not distinguishable from the heart. Baltic white deal is recognised chiefly by its small hard and dark knots, by its woolliness on leaving the saw, and by its weathering to a greyish tint. When fresh cut, the grain may be more or less pronounced than that of yellow deal. It is subject to streaks of resin in long cavities, and to loose dead knots. ”

“ Every broken limb or root, or deep wound from fire, insects, or falling timber, may afford an entrance for decay, which, once started, may penetrate to all parts of the trunk. The larvæ of many insects bore into the trees and their tunnels remain indefinitely as sources of weakness. Whatever advantages, however, that sapwood may have in this connection are due solely to its relative age and position.
If a tree grows all its life in the open and the conditions of soil and site remain unchanged, it will make its most rapid growth in youth, and gradually decline. ”

“ The weight of sapwood or the sappy, peripheral part of our common lumber woods is always great, whether cut in winter or summer. It rarely falls much below forty-five pounds, and commonly exceeds fifty-five pounds to the cubic foot, even in our lighter wooded species. ”

“ They were formerly very abundant near the mouth of the Susquehanna river in Maryland and Pennsylvania, and northward through New Jersey; but the traffic in the flowers has destroyed the growth in many places where once plentiful. It is not important as a timber resource, but it is employed for a number of useful purposes where logs of fair size may be had. The sapwood is creamy-white, but the heart is nearly as dark as mahogany, and in Texas it is used to imitate that wood. ”

“ As a tree increases in age and diameter an inner portion of the sapwood becomes inactive and finally ceases to function. This inert or dead portion is called heartwood, deriving its name solely from its position and not from any vital importance to the tree, as is shown by the fact that a tree can thrive with its heart completely decayed. ”

“ Trees or rarely shrubs, with deeply furrowed and sometimes laminate or with thin and scaly bark, hard or often soft heartwood often conspicuously marked by dark bands of summer cells impregnated with resin, pale nearly white sapwood, and large branch-buds formed during summer and composed of minute buds in the axils of bud-scales, becoming the bracts of the spring shoot. ”

“ The Wood.—The heartwood is a light, clean yellow. The sapwood is a dirty white. Frequently the whole wood is a dirty white or grey, but this is due to discolourations from mould and the wood should always be seasoned in dry air and not allowed to get wet. ”

“ Thaw and Rain and Freshet and Wind, the whole pack in full cry, toward the Orono Mills. Every log is marked with the owner's name, cut in the sapwood with an axe or bored with an auger, so deep as not to be worn off in the driving, and yet not so as to injure the timber; and it requires considerable ingenuity to invent new and simple marks where there are so many owners. They have quite an alphabet of their own, which only the practised can read. ”

“ 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 ”

“ The heartwood of wahoo is white, with a slight tinge of orange. The sapwood, scarcely distinguishable from the heartwood, is more nearly white in tone. The wood is heavy and close-grained but not very hard. It weighs when seasoned a little less than forty pounds to the cubic foot. Such of this wood as is sawed into lumber, which is but a small quantity, sells commercially with poplar saps, thus masquerading like its forest fellow, the cucumber tree. The character of the wood is such that it will not stand exposure to the weather any length of time. ”