Chapter XXV: Introduction (1)

A tree has been defined as a woody plant that produces naturally and in its native place one principal erect stem with a definite crown of foliage. A plant thus attaining to the dignity of a tree is said to be arborescent.[1]

There are nearly five hundred distinct species of trees growing in the United States,[2] as well as many others peculiar to other countries, yet the great mass of wood everywhere utilized is derived from comparatively few of them.[3] Many woods will be more generally employed as their valuable properties become more familiar or as the supplies of wood now utilized continue to diminish.

The same tree is often called by different common names in different places. Nearly thirty names are thus applied to the longleaf pine (_Pinus palustris_). Such confusion can be avoided only by regarding the recognized botanical nomenclature.

The botanical name of a plant consists of two principal terms denoting genus and species. Quercus, for example, is [p002] the generic name including all species of oak. Alba, rubra, and others are specific names denoting the said species. Quercus alba and Quercus rubra are completed terms. Genera are not fixed but differ with authorities, so that the abbreviated name of the botanist responsible for the classification adopted is often added, as Quercus alba Linn. and Ulmus fulva Michx.

A species is a collection of individuals that might well have sprung from some single root. A genus is a collection of related species. Genera are gathered into families. Families and genera differ with authorities. A variety includes individuals differing slightly from accepted species. Its name when existing is part of the specific name. "Quercus robur var. pedunculata" specifies a variety (pedunculata) of "red" or strong (robur) oak (Quercus). A variety of one botanist is sometimes a distinct species of another.

The size and character of the trunk, and the range, locality, or distribution of the tree, have much to do with the utility of the wood, since large or perfect timbers cannot be derived from species characterized by small or crooked trees, and since wood is always more used if it is widely distributed so as to be easily available.[4]

Wood is made up of cell-structures; as, the true fibre, which originates from several cells; the tracheid (tra-ke-id), which originates from one; the vessel, which is a short, wide tube joined vertically end to end with others of its kind; the pith-ray; the resin-duct, and others,--all of which are often popularly referred to as fibres. [p003]

The character and the arrangement of cell-structures differ with species. Wood is hard, soft, light, heavy, tough, porous, elastic, or otherwise, because of these differences. Appearance is affected, and woods may be distinguished from one another, because of this fact.[5]

Most wood is used in "construction," that is, in mines, railways, houses, and ships, where demand is for size or quantity, and where finish and appearance amount to but little. Much wood is used in decoration and furniture, where appearance, appropriateness, and finish are called for; but these woods, although much in evidence, are infinitely less in quantity than those employed in construction. Some wood is required for implements, turnery, carvings, and small-piece work, where size is secondary and where qualities such as hardness, fine grain, and uniformity, controllable in small pieces, are primary. Some wood is used indirectly, as in the manufacture of paper-pulp, gunpowder, and chemicals. There are also by-products of trees, such as tanbark, turpentine, resin, nuts, and sugar.

The weight, strength, and other measurable properties of wood are variable. Weight varies from day to day as water is absorbed and evaporated. Strength differs with grain, age, moisture, specific gravity, and many other things. Two pieces from different portions of the same tree differ from each other. The proportions of sap and heart wood are seldom constant. Results from small specimens may differ from those obtained from larger ones.[6] The botanical accuracy of a specimen is not always certain, therefore figures relating to the physical properties of wood should be employed with greater caution than those relating to the more homogeneous metals.

Many of the experiments conducted to establish statements regarding the physical properties of wood have been defective [p004] in that while the conclusions were correct as applied to the specimens immediately studied, such specimens did not stand for the species at large. The recognition of difficulties, the selection of specimens, the scientific standardizing of methods so that results could be generally utilized, as distinct from the simple manipulation of specimens in testing-machines, have not been exhaustively attempted until recently.[7]

The experiments that have been made to determine the strength of woods may be grouped into the four following divisions:

(1) Experiments conducted by the U. S. Division of Forestry (Dr. B. E. Fernow, Chief), under the direction of Professor J. B. Johnson. About forty thousand tests were made, distributed over thirty-one American species, the results, so far as obtained, being undoubtedly the most valuable in existence. The detail considered and methods evolved have in a way reclassed the testing of woods and must influence all future efforts, but results are disappointing in that they have been obtained for so few species, and some of these of commercially secondary importance. These experiments are characterized as follows:

Completeness and Reliability of Records. Large and Small Test Pieces. Moisture Conditions Standardized at 12% Dry Weight. Samples from Representative Portions of Tree. Selection of Representative Trees. Uniformity of Methods. Large Number of Individual and Total Tests. Small Number of Species Covered. Specific Gravity Determinations. Soil and Forest Conditions Indicated. Botanical Accuracy Assured.

These experiments are originally described in Circular No. 15 and other publications of the U. S. Forestry Division, also in "Materials of Construction," by Professor J. B. Johnson.

(2) Experiments conducted for the Tenth U. S. Census by Mr. J. P. Sharpless at the Watertown (Mass.) Arsenal upon specimens botanically selected by Professor Sargent. These experiments are less complete in detail, and averages are based upon infinitely [p005] fewer tests for each species. So far as known most specimens were from butts. Nothing is known of moisture conditions save that specimens were "carefully seasoned." Tests were upon about twelve hundred specimens divided over four hundred and twelve species, allowing but a small number for each. The series is most valuable in that the species attempted were so numerous as to present an almost complete American series; in that the botanical identity of the specimens was beyond question, and because it gives a general idea of relative values. The results are frequently quoted and appear on the accompanying pages in spaces immediately following those occupied by, or set apart for, "Forestry" figures or their alternates. The tests are characterized as follows:

Botanical Accuracy Assured. Specific Gravity Determinations. Uniformity of Methods. Limited Number of Individuals and Total Tests. Large Number of Species Covered. Small Test Pieces Only. Selection and Moisture Conditions Indefinite.

They are originally described in Vol. IX, Tenth U. S. Census; Executive Document No. 5, Forty-eighth Congress, First Session; in Catalogue of the "Jesup Collection," by Professor C. S. Sargent, and elsewhere.

(3) Experiments conducted upon full-sized pieces. The most reliable investigations under this head were either conducted by Professor Lanza, of the Massachusetts Institute of Technology, or else are noted by him in his work, "Applied Mechanics" (ed. 1895, pp. 673-711). They are valuable in that specimens were selected on a commercial rather than on a scientific basis. Professor Lanza claims that such actual pieces are less perfect and show approximately one half the unit strength developed by the more carefully selected smaller specimens. These experiments are characterized as follows:

Life-sized Specimens. Miscellaneous Selections as if for Practical Construction. Moisture and Other Data Indefinite.

(4) All other experiments. Many experiments have been made from time to time which, while valuable, are not distinguished by any particular method or principle, such as separate the investigations noted in the preceding articles. Data as to selection of specimens, moisture, and other conditions are either incomplete or else absolutely lacking. Such tests are referred to as are noted in works of Hatfield, Trautwein, Lazlett, Rankine, Thurston, and others. Some of these series are exceedingly valuable comparatively. Professor Rankine and Mr. Lazlett experimented principally upon foreign woods. [p006]

The figures established by the United States Division of Forestry and alluded to in item 1, page 4, appear, so far as they exist, upon the following pages. Where they do not exist, the leading spaces set apart for them are left vacant for other insertions as preferred. All coefficients are in pounds per square inch. Fractions of pounds in weight and lower figures in coefficients have been omitted as superfluous.

It is not always easy to determine the species of living trees, because forms in the forest differ from those in the open, because bark varies with age, and because fruit and leaves of many trees are lacking in the winter. It is easier to tell genus than species--that a tree is an oak, than whether it is a red or a pin oak. Experience is required in this connection.

Trees are divided into two general divisions known as Exogens and Endogens.[8] [p007]

FOOTNOTES

[Footnote 1: Fernow, Introduction to U. S. Forestry Bul. No. 17.]

[Footnote 2: Dr. Fernow credits 495 trees to United States (Introduction to U. S. Forestry Bul. No. 17); Prof. Sargent, counting species only and excluding varieties, gives 422 (Silva of North America).]

[Footnote 3: "The principal timbers of commerce in the United States are the species known popularly as pine, fir, oak, hickory, hemlock, ash, poplar, maple, cypress, spruce, cedar, and walnut." ("The Lumber Trade of the United States," Treas. Dept., Bureau of Statistics.)]

[Footnote 4: Fossils show that many species covered wider ranges than at present.]

[Footnote 5: Roth, U. S. Forestry Bul. No. 10, pp. 64-71. Also von Schrenk, U. S. Dept. Agriculture, Bureau Plant Industry Bul. No. 14, pp. 12-16.]

[Footnote 6: Only because imperfections are more likely in larger pieces. Large and small pieces of equally perfect wood are equally strong. (See Publications U. S. Forestry Div. and J. B. Johnson's "Materials of Construction," p. 462.)]

[Footnote 7: It should be noted that the selection and preparation of specimens require the exercise of more judgment than the simple testing of specimens, if the conclusions are to be such that they can be generalized from.]

[Footnote 8: This division coincides with that by which they are separated into Dicotyledons and Monocotyledons.]

EXOGENOUS TREES. (_Dicotyledons_.)

Exogenous trees are those the trunks of which are built up by rings or layers, each deposited consecutively upon the outside of the others. A section exhibits first a central point or canal known as a pith-cavity, next and consecutively the annual layers, and finally the bark. The woods of this series are familiar to all. The oaks, pines, and practically all of the merchantable lumbers are among them. The forests are widely distributed, and the species are so numerous as to present an almost infinite range of possibilities.

The young wood of exogenous trees is porous. It permits the passage of sap and is known as sapwood (Alburnum). As a layer is enclosed by others and retreats from the surface of the tree, it becomes denser, its canals are filled with gums or tannin, color changes, and the result is heartwood (Duramen). This change goes forward rapidly in some trees, such as locusts, so that their sections appear to be almost wholly heartwood; other species require longer time, and sapwood then predominates.

Heartwood gives stability to the tree, but is not needed in its physiological processes. It is tougher, heavier, stronger, and more valued in construction. Sapwood is vitally essential to the life of the tree, but is lighter, weaker, less durable, and less valued in construction. Sapwood is pliable, and the sapwoods of several trees are valued for this reason.

Wood-making varies as it takes place in the springtime and in the summer. Consequent differences in the densities [p008] of the deposits serve to mark the limits of the yearly rings. Some species, as the oaks and hickories, show pores throughout their spring woods which thus contrast with denser summer growths. Others, as Southern pines, change sharply, and their spring and summer growths appear as solid bands. In even climates, where seasons are not pronounced, growth is more regular and layers correspondingly less definite.[9]

The cellular structure of wood is principally vertical, a fact that explains the ease with which wood is split up and down. Beside the vertical, there are horizontal cells, that cross the tree, strengthen and bind the vertical cells, and assist in the life-processes of the tree. These horizontal cells form what are known as medullary or pith-rays and appear as simple lines or glistening plates according to the way in which the wood is cut. Woods differ in the size and number of these rays, which are by no means always visible to the eye (see plate 3).

Woods are easy or difficult to work in proportion as their fibres are arranged in a simple or a complicated manner. This is shown in the figures on plate 4. A knife pressed upon the oak must crush or cut into the fibres themselves, whereas with the pine it finds some natural passage between the cells. Wood may be cut so as to develop cross-sections (_C_, Fig. 3), radial sections (_R_), or tangential sections (_T_). The respective [p009] markings are in a general way indicated on the boards in the figure.

Two yearly layers of White Oak. The larger pores were formed in
spring, the smaller ones in summer. The small circles are ends of
fibres. A knife pressed upon this surface would crush or cut into
the cells. The mass would not split or separate evenly.

Two yearly layers of White Pine. The space in the outer or darker
one is a resin-duct; the circles are ends of fibres (tracheids);
pith rays are noticeable. A knife pressed upon this surface would
find easy passage. The mass would separate easily.]

Logs are sometimes sawn into quarters and then into pieces crossing and exposing the yearly rings. (See Fig. 4.) These "quarter-sawn" surfaces are structurally stronger and better, but are, by reason of waste or small pieces, more costly than others. The pith-rays of some woods, such as oaks, are very prominent when split as they are in "quarter-sawing," and the appearance of such woods is consequently improved.[10]

Exogenous trees are divided into broad-leaved trees and needle-leaved conifers. The broad, flat leaves of trees such as oaks and chestnuts gave rise to the former term, while the narrow resinous leaves of the pine and hemlock gave rise to the latter. The woods of the former group are usually referred to as hard woods, although some of them are very soft; those of the latter group are referred to as soft woods, although some of them are very hard. Most, but not all, of the broadleaf trees are deciduous, that is, they change their foliage every year; and most, but not all, of the needleleaf trees are evergreen, that is, the foliage is persistent. Needleleaf trees are also known as conifers, that is, cone-bearers.

It is usual to associate the terms broadleaf, deciduous, and hard wood; and likewise the terms needleleaf, conifer, evergreen, and soft wood. While generally correct, this is, as seen, not always so. A better division is into broadleaf trees or woods, and needleleaf conifers. [p010]

BROADLEAF WOODS.

The trees affording these woods are found in natural forests and under cultivation in nearly every portion of the globe. The histories of some of them extend back to very remote periods. Their woods were the principal ones in construction until the advent of American soft woods. The oaks, elms, maples, and other so-called hard woods are of this group.

Broadleaf woods are characterized by complex fibre conditions, absence of resins, and greater weights.[11] They are composed of several kinds of cells and fibres, arranged without the regularity so noticeable in the conifers. Cross-sections exhibit numerous, often easily visible pores, arranged in zones or scattered throughout the rings (see plate 2). Pith-rays are numerous and more or less conspicuous, save in softer hard woods such as poplar. Woods are difficult to work in proportion as they are complicated in structure. The numerous members of the group vary from one another and present an extensive range of properties. Trees do not usually afford large pieces. Woods for cabinet work, implements, and other fine purposes are from this group. The total requirement is less than for needleleaf woods.

The leaves of broadleaf trees are easily distinguished from the resinous, usually evergreen ones of the conifers. Most of them are deciduous, that is, shed every season, although some are persistent, that is, "evergreen." "Broadleaf," "deciduous," and "hardwood" trees are the same. [p011]

FOOTNOTES

[Footnote 9: Circular No. 16, U. S. Forestry Division.]

[Footnote 10: Some woods, as birdseye maple, are well developed by the rotary cut. A revolving log is advanced against a tool which pares a broad thin ribbon suitable for veneered work.]

[Footnote 11: Neither resin-ducts nor resin exists in these woods, save sometimes in buds and leaves.]

OAK. (_Quercus_.)

The oaks are found on all of the continents of the northern hemisphere, as well as at high altitudes just south of the equator. Their woods stand pre-eminent among those of the broadleaf series and have been highly prized from early periods. Formerly relied upon for all purposes of house and naval architecture, they did not give way to the so-called "soft woods" for houses, and to iron for vessels, until comparatively recent periods. They were supplanted for the former purposes upon the opening of the soft-wood forests of North America and of the Baltic, and for vessels subsequent to the conclusions of the American Civil War.

The historical importance of oak is founded upon the reputation of the English Oak as derived from two trees, Quercus robur var. pedunculata and Quercus robur var. sessiliflora, usually taken as sub-species of Quercus robur.[12] It is said that these trees once formed large forests over Northern and Central Europe. Live-oak has always been highly esteemed, but is now very scarce. It is one of the hardest, heaviest, and most durable of constructive woods and was once largely employed in ship-building. The wood of the White Oak (_Quercus alba_) is at present preferred for most purposes for which oak is now employed, and is one of the most valuable of the American hard woods.

Oak is tough, durable, easily obtained, liable to warp and check in seasoning, often hard to nail without splitting, susceptible of high polish, and not greatly liable to attack by insects. It contains gallic acid, causing peculiar taste and odor and attacking iron, the solutions staining the wood. Experiments[13] indicate that iron fastenings are shortly protected by an insoluble scale of resulting salt, and that the wood, although [p012] darkened, remains practically uninjured. The later oaken vessels were iron-fastened,[14] and cabinet-makers now employ that metal in joining oak. The barks of all species are also so charged with acid as to be used in the tanning of leather. The several kinds of oak are commercially divisible into three general groups, white oak, red or black oak, and live oak.[15] The principal species affording woods under each head are as follows:

White Oak. White Oak (Q. alba). Cow Oak (Q. michauxii). Chestnut Oak (Q. prinus). Post Oak (Q. minor). Bur Oak (Q. macrocarpa). Pacific Post Oak (Q. garryanna).

Red or Black Oak. Red Oak (Q. rubra). Pin Oak (Q. palustris). Spanish Oak (Q. digitata). Yellow or Black Oak (Q. velutina).

Live Oak. Live Oak (Q. virginiana). California Live Oak (Q. agrifolia). Live Oak (Q. chrysolepis)

Oak trees are characterized by oblong, thin-shelled kernels, protruding from hard scaly cups and called acorns. The foliage is sometimes deciduous and sometimes evergreen. Most oaks require many years to reach maturity, but are then long-lived. Fifty of the nearly three hundred known species of oak are natives of the United States and Canada; all but four become trees under favorable conditions. Quercus is from two Celtic words, _quer_, signifying fine, and _cuex_, a tree. [p013]

FOOTNOTES

[Footnote 12: Thought by some botanists to be distinct species, namely, Quercus pedunculata and Quercus sessiliflora.]

[Footnote 13: Havemeyer Chemical Laboratory, N. Y. University.]

[Footnote 14: Communication. Mr. Chas. H. Cramp, President Cramp Ship-building Co., Philadelphia.]

[Footnote 15: This division is also a botanical one based not only on differences in anatomical structure of the wood itself, but on the time required by fruit in attaining maturity, and on persistence of foliage (evergreen or deciduous), etc.]

WHITE OAK. _Quercus alba Linn._

Nomenclature.

White Oak (general).

Stave Oak (Ark.).

Locality.

Widespread, north-central and eastern United States.

Features of Tree.

Seventy-five to one hundred feet in height. Three to six feet in diameter, fine shape and appearance. Grayish-white bark. Comparatively sweet ovoid oblong acorns in rough shallow cups. Rounded lobes or projections to leaves.

Color, Grain, or Appearance of Wood.

Heartwood brown with sapwood lighter. Annual layers well marked.

Medullary rays broad and prominent.

Structural Qualities of Wood.

Tough, strong, heavy, hard, liable to check unless seasoned with care. Durable in contact with the soil. Receives a high polish.

Representative Uses of Wood.

Ship-building, construction, cooperage, cabinet-making, railway ties, fuel, etc. Bark is rich in tannin.

Weight of Seasoned Wood in Pounds per Cubic Foot.

50 (U. S. Forestry Div.).[16]

46.

Modulus of Elasticity.

2,090,000 (average of 218 tests by U. S. Forestry Div.).[16]

1,380,000.

Modulus of Rupture.

13,100 (average of 218 tests by U. S. Forestry Div.).[16]

12,800.

Remarks.

A tree of the first economic importance. The most widely employed of all American oaks. Name refers to appearance of bark. The supply diminishing because of value of timber, also the sweetness of nuts cause them to be eaten by animals. [p014]

FOOTNOTE

[Footnote 16: See page 6.]

COW OAK. _Quercus michauxii Nutt._

Nomenclature. (Sudworth.)

Cow Oak (local and common name).

Basket Oak (Ala., Miss., La., Tex., Ark.).

Swamp White Oak (Del., Ala.).

Swamp Chestnut Oak (Fla.).

Locality.

Southeastern United States, Delaware and Florida, westward along Gulf to Texas. Also southern Indiana and Illinois to Gulf. Best on rich bottoms in Arkansas and Louisiana.

Features of Tree.

Seventy-five to one hundred feet in height. Three to six feet in diameter, rough, light-gray bark with loose scaly ridges.

Color, Appearance, or Grain of Wood.

Heartwood light brown, light buff sapwood, conspicuous medullary rays, close-grained.

Structural Qualities of Wood.

Hard, heavy, very strong, tough, durable, easily split.

Representative Uses of Wood.

Construction, agricultural implements, wheel stock.

Weight of Seasoned Wood in Pounds per Cubic Foot.

46 (U. S. Forestry Div.).[17]

50.

Modulus of Elasticity.

1,610,000 (average of 256 tests by U. S. Forestry Div.).[17]

1,370,000.

Modulus of Rupture.

11,500 (average of 256 tests by U. S. Forestry Div.).[17]

15,800.

Remarks.

The principal white oak of Southern States; edible acorns devoured by cattle, whence its name. [p015]

FOOTNOTE

[Footnote 17: See page 6.]

CHESTNUT OAK. _Quercus prinus Linn._

Nomenclature. (Sudworth.)

Chestnut Oak (local and common name).

Rock Oak (N. Y., Del., Pa.).

Rock Chestnut Oak (Mass., R. I., Pa., Del., Ala.).

Tanbark Oak (N. C.).

Swamp Chestnut Oak (N. C).

Mountain Oak (Ala.).

Locality.

Maine to Georgia, westward intermittently to Kentucky and Alabama. Best development in southern Alleghany Mountain region.

Features of Tree.

Seventy-five to eighty feet in height, three or four feet in diameter. Leaves resemble those of chestnut.

Color, Appearance, or Grain of Wood.

Heartwood dark brown, sapwood lighter, close-grained, medullary rays conspicuous.

Structural Qualities of Wood.

Heavy, tough, hard, strong, and durable in contact with soil.

Representative Uses of Wood.

Largely used for railway ties. Bark rich in tannin.

Weight of Seasoned Wood in Pounds per Cubic Foot.

46.

Modulus of Elasticity.

1,780,000.

Modulus of Rupture.

14,600.

Remarks.

Prinus is a Greek name applied to a species of oak. [p016]

POST OAK. _Quercus minor Sargent_, _Quercus obtusiloba Michx._

Nomenclature. (Sudworth.)

Post Oak (local and common name).

Iron Oak (Del., Miss., Neb.).

Box White Oak (R. I.).

Chêne étoilé (Quebec).

Overcup Oak (Fla.).

White Oak (Ky., Ind.).

Box Oak (Md.).

Brash Oak (Md.).

Locality.

East of Rocky Mountains--Massachusetts to northern Florida, westward intermittently to Nebraska and Gulf States.

Features of Tree.

Fifty to seventy feet in height, two to three feet in diameter. Low shrub in Florida. Blunt lobes or projections to leaves. Leaves clustered at ends of branches. Fine tree with rounded top.

Color, Appearance, or Grain of Wood.

Heartwood light or dark brown with lighter sapwood. Close-grained, annual rings well marked. Numerous and conspicuous medullary rays.

Structural Qualities of Wood.

Heavy, hard, strong, checks badly in drying. Durable in contact with soil.

Representative Uses of Wood.

Largely used, particularly in Southwest, for fencing, railway ties, and fuel; also for cooperage, construction, etc.

Weight of Seasoned Wood in Pounds per Cubic Foot.

50 (U. S. Forestry Div.).[18]

52.

Modulus of Elasticity.

2,030,000 (average of 49 tests by U. S. Forestry Div.).[18]

1,180,000.

Modulus of Rupture.

12,300 (average of 49 tests by U. S. Forestry Div.).[18]

12,900.

Remarks.

Most common and widely distributed oak in Gulf States west of the Mississippi River. Obtusiloba, the Latin for blunt-lobed, refers to the shapes of the leaves. Wood seldom commercially distinguished from white oak. [p017]

FOOTNOTE

[Footnote 18: See page 6.]

BUR OAK. _Quercus macrocarpa Michx._

Nomenclature. (Sudworth.)

Bur Oak (local and common name).

Overcup Oak (R. I., Del., Pa., Miss., La., Ill., Minn.).

Mossycup White Oak (Minn.).

Mossycup Oak (Mass., Pa., Del., Miss., La., Tex., Ark., Ill., Iowa, Neb., Kan.).

Scrub Oak (Neb., Minn.).

Overcup White Oak (Vt.).

Locality.

New Brunswick, New England, westward intermittently to Montana and Texas.

Features of Tree.

Seventy to one hundred and thirty feet in height, five to seven feet in diameter. Deep opposite depressions to leaves. Mossy, fringed border at top of acorn-cup. Corky wings on young branches.

Color, Appearance, or Grain of Wood.

Heartwood rich brown, sapwood lighter, close-grained, broad conspicuous medullary rays.

Structural Qualities of Wood.

Heavy, hard, strong, tough, very durable in contact with ground.

Representative Uses of Wood.

Similar to those of Quercus alba.

Weight of Seasoned Wood in Pounds per Cubic Foot.

46.00.

Modulus of Elasticity.

1,320,000.

Modulus of Rupture.

13,900.

Remarks.

Extends farthest west and northwest of any other Eastern oak. Especially recommended for prairie planting. [p018]

WHITE OAK. _Quercus garryana Douglas._

Nomenclature. (Sudworth.)

White Oak (Cal., Oreg.).

Pacific Post Oak (Oreg.).

Western White Oak (Oreg.).

Oregon White Oak (Cal.).

California Post Oak.

Locality.

Pacific coast, British Columbia into California.

Features of Tree.

Sixty to ninety feet high, one and one half to two and one half feet in diameter. A small shrub at high elevations.

Color, Appearance, or Grain of Wood.

Heartwood light brown or yellow. Sapwood lighter, often nearly white. Compact structure. Distinctly marked annual rings. Medullary rays often conspicuous.

Structural Qualities of Wood.

Heavy, strong, hard, tough.

Representative Uses of Wood.

Ship-building, carriages, furniture, indoor decoration, fuel.

Weight of Seasoned Wood in Pounds per Cubic Foot.

46.

Modulus of Elasticity.

1,150,000.

Modulus of Rupture.

12,400.

Remarks.

Locally important. The best substitute for Eastern White Oak produced on Pacific coast. [p019]

RED OAK. _Quercus rubra Linn._

Nomenclature. (Sudworth.)

Red Oak (local and common name).

Black Oak (Vt., Conn., N. Y., Wis., Ia., Neb., So. Dak., Ont.).

Spanish Oak (Pa., N. C.).

Locality.

East of Rocky Mountains, Nova Scotia to Georgia, westward intermittently to Nebraska and Kansas, best in Massachusetts.

Features of Tree.

Ninety to one hundred feet in height. Three to six feet and over in diameter, brownish-gray bark smooth on branches. Leaves have sharp-pointed lobes, very large acorns in flat shallow cups. A fine complete tree.

Color, Appearance, or Grain of Wood.

Heartwood light brown or red, sapwood darker, coarse-grained, well-marked annual rings, medullary rays few but broad.

Structural Qualities of Wood.

Heavy, hard, strong, inclined to check in drying, acid, inferior to white oak.

Representative Uses of Wood.

Works of secondary importance, clapboards, cooperage, fuel.

Weight of Seasoned Wood in Pounds per Cubic Foot.

45 (U. S. Forestry Div.).[19]

40.

Modulus of Elasticity.

1,970,000 (average of 57 tests by U. S. Forestry Div.).[19]

1,600,000.

Modulus of Rupture.

11,400 (average of 57 tests by U. S. Forestry Div.).[19]

140,000.

Remarks.

Grows more rapidly than other oaks. Bark used in tanning. [p020]

FOOTNOTE

[Footnote 19: See page 6.]

PIN OAK. _Quercus palustris Muenchh._

Nomenclature. (Sudworth.)

Pin Oak (local and common name).

Swamp Spanish Oak (Ark., Kan.).

Water Oak (R. I., Ill.).

Swamp Oak (Pa., Ohio, Kans.).

Water Spanish Oak (Ark.).

Locality.

Minnesota to Kansas, eastward intermittently to Massachusetts and Virginia.

Features of Tree.

Fifty to eighty feet in height, two to four feet in diameter. Full-rounded or pyramidal top, smooth thin bark, numerous small pin-like branches.

Color, Appearance, or Grain of Wood.

Heartwood variegated light brown, sapwood nearly white, coarse-grained, medullary rays numerous and conspicuous.

Structural Qualities of Wood.

Heavy, hard, strong, checks badly in seasoning.

Representative Uses of Wood.

Shingles, clapboards, construction, interior finish, cooperage.

Weight of Seasoned Wood in Pounds per Cubic Foot.

43.

Modulus of Elasticity.

1,500,000.

Modulus of Rupture.

15,400.

Remarks.

Palustris, the Latin for swampy, refers to favorite location of tree. The numerous slender secondary branches suggesting pins cause tree to be easily recognized, particularly in winter. [p021]

SPANISH OAK. _Quercus digitata Sudworth_, _Quercus falcata Michx._

Nomenclature. (Sudworth.)

Spanish Oak (local and common name).

Red Oak (N. C., Va., Ga., Fla., Ala., Miss., La., Ind.).

Spanish Oak (La.).

Locality.

New Jersey and Florida, westward intermittently to Illinois and Texas.

Features of Tree.

Thirty to seventy feet in height, two and one half to four feet in diameter. Variable foliage. Globular to oblong acorns.

Color, Appearance, or Grain of Wood.

Heartwood light red, sapwood lighter, coarse-grained, annual layers strongly marked, medullary rays few but conspicuous.

Structural Qualities of Wood.

Hard, heavy, strong, not durable, checks badly in drying.

Representative Uses of Wood.

Somewhat used for cooperage, construction, etc. Bark very rich in tannin.

Weight of Seasoned Wood in Pounds per Cubic Foot.

43.

Modulus of Elasticity.

1,900,000.

Modulus of Rupture.

16,900.

Remarks.

Dry barren soils. Grows rapidly. [p022]

BLACK OAK, YELLOW OAK. _Quercus velutina Lam._ _Quercus tinctoria Barti._

Nomenclature. (Sudworth.)

Black Oak, Yellow Oak (local and common names).

Yellow Bark, Yellow-bark Oak (R. I., Minn.).

Dyer's Oak (Tex.).

Tanbark Oak (Ill.).

Spotted Oak (Mo.).

Quercitron Oak (Del., S. C., La., Kans., Minn.).

Locality.

East of longitude 96 degrees, Maine and Florida, westward intermittently to Minnesota and Texas. Best in North Atlantic States.

Features of Tree.

Ninety to one hundred and thirty feet in height, three to five feet in diameter. Dark gray to black bark, yellow inner bark. Acorns have bitter yellow kernels. Foliage turns handsomely in autumn.

Color, Appearance, or Grain of Wood.

Heartwood light reddish brown, sapwood lighter, coarse grain, annual layers strongly marked, thin medullary rays.

Structural Qualities of Wood.

Heavy, hard, strong, liable to check in drying, not tough.

Representative Uses of Wood.

Cooperage, construction, furniture, and decoration.

Weight of Seasoned Wood in Pounds per Cubic Foot.

45 (U. S. Forestry Div.).[20]

44.

Modulus of Elasticity.

1,740,000 (average of 40 tests by U. S. Forestry Div.).[20]

1,470,000.

Modulus of Rupture.

10,800 (average of 40 tests by U. S. Forestry Div.).[20]

14,800.

Remarks.

Yellow inner bark affords yellow dye. [p023]

FOOTNOTE

[Footnote 20: See page 6.]

LIVE OAK. _Quercus virginiana Mill._ _Quercus virens Ait._

Nomenclature. (Sudworth.)

Live Oak (Va., N. C., S. C., Ga., Fla., Miss., Ala., Tex., La., Calif.).

Chêne Vert (La.).

Locality.

Southern States--coast from Virginia to Florida, westward to Texas and Lower California, southern Mexico, Central America, and Cuba. Best in south Atlantic States.

Features of Tree.

Fifty to sixty feet high, diameter three to six feet. General resemblance to apple-tree. Evergreen foliage.

Color, Appearance, or Grain of Wood.

Heartwood light brown or yellow, sapwood nearly white, close-grained, compact structure, pronounced medullary ray, annual layers often hardly distinguishable.

Structural Qualities of Wood.

Heavy, strong, tough, hard, difficult to work, splits easily. Receives high polish, very durable.

Representative Uses of Wood.

Ship-building.

Weight of Seasoned Wood in Pounds per Cubic Foot.

59.

Modulus of Elasticity.

1,600,000.

Modulus of Rupture.

14,000.

Remarks.

Trunk and branches furnish small straight pieces, but principally knees, crooked or compass timbers. Virens refers to evergreen foliage. Splits so easily that it is better fastened with bolts or trenails than spikes. Now scarce, grows rapidly. [p024]

CALIFORNIA LIVE OAK. _Quercus agrifolia Nee._

Nomenclature. (Sudworth.)

Coast Live Oak (Cal.).

California Live Oak (Cal.).

Encena (Cal.).

Evergreen Oak (Cal.).

Locality.

California.

Features of Tree.

Forty to seventy-five and occasionally more feet in height, three to six feet in diameter. Evergreen foliage, leaves spiked like those of holly. Shape resembles that of apple tree.

Color, Appearance, or Grain of Wood.

Heartwood creamy white, but darkens on exposure. Compact structure, annual layers hardly distinguishable.

Structural Qualities of Wood.

Heavy, hard, but brittle.

Representative Uses of Wood.

Fuel.

Weight of Seasoned Wood in Pounds per Cubic Foot.

51.

Modulus of Elasticity.

1,350,000.

Modulus of Rupture.

13,200.

Remarks.

Agrifolia is from the Latin _acer_, sharp, and _folium_, leaf, alluding to the spinous toothed leaves. [p025]

LIVE OAK. _Quercus chrysolepis Liebm._

Nomenclature. (Sudworth.)

Live Oak (Cal., Oreg.).

Canyon Live Oak, Black Live Oak, Golden-cup Oak (Cal.).

Canyon Oak, Iron Oak, Maul Oak, Valparaiso Oak (Cal.).

Locality.

West of Rocky Mountains, canyons, and high elevations.

Features of Tree.

Fifty to eighty feet in height, three to six feet in diameter. Often low shrub. Impressive appearance. Evergreen foliage.

Color, Appearance, or Grain of Wood.

Heartwood light brown, sapwood lighter, small pores in wide bands parallel to conspicuous medullary rays. Close-grained.

Structural Qualities of Wood.

Hard, heavy, strong, tough, difficult to work.

Representative Uses of Wood.

Implements, wagons, tool-handles.

Weight of Seasoned Wood in Pounds per Cubic Foot.

52.

Modulus of Elasticity.

1,700,000.

Modulus of Rupture.

18,000.

Remarks.

Said to be the most valuable of the California oaks. Grows at elevations of 2000 to 5000 feet. Highland Oak (_Quercus wislizeni_) is an evergreen and a Pacific Coast variety. [p026]

ENGLISH OAK. _Quercus robur var. pedunculata._

Nomenclature.

English Oak.

British Oak.

Common Oak.

Locality.

Widespread throughout northern and central Europe.

Features of Tree.

Seventy to one hundred feet in height, eight to ten feet in diameter. Crooked branches, stalkless leaves, long-stalked acorns.

Color, Appearance, or Grain of Wood.

Heartwood light brown, darker spots frequent, sapwood lighter. Compact structure.

Structural Qualities of Wood.

Hard, tough, strong, durable, difficult to work, liable to warp in seasoning.

Representative Uses of Wood.

Ship-building, beams, cabinet-work, formerly carpentry.

Weight of Seasoned Wood in Pounds per Cubic Foot.

51 (Laslett).

Modulus of Elasticity.

1,170,000 (Thurston).

Modulus of Rupture.

10,000 (Thurston).

Remarks.

The English, Chestnut, Durmast, or Red Oak, Q. robur var. sessiliflora, distinguished by long leaf stalks and short acorn stalks, affords practically similar but lower-rated wood. The two varieties supply the British Oak of commerce. Dantzic, Rigi, and some other European oaks take names from port of shipment. Rubrus is red, but robur is a noun meaning strength; the adjective robustus means "oaken" or vigorous. [p027]

ASH. (_Fraxinus_.)

Ash is widely distributed over the temperate regions of the northern hemisphere, and occurs in the tropics, on the island of Cuba. The tree has occupied a position second only to that of oak. Our Teutonic forefathers relied upon its wood for boats and weapons. Their ancient faith connects it with the creation of the original man. It is often associated with oak in country proverbs.[21] Europeans regard the trees for ornamental purposes, but Americans value them for wood.

Ash and oak woods resemble one another in that there are bands of open pores in both woods, but the pith-rays of the ash are thinner and scarcely discernible. Ash is coarser, less attractive, easier to work, tough, elastic, and somewhat lighter than oak. It seasons well, but does not last when exposed to the weather. Lumbermen separate the woods into white and black ash, the former including the lighter-colored and more desirable pieces. This commercial division is also a botanical one in the North, where the only species of any note are the white ash and black ash (_F. americana_ and _F. nigra_). The Southern green ash (_F. lanceolata_) is usually classed as white ash. The trees that grow up after the cutting of the virgin forest afford tougher, more pliable, but not necessarily stronger pieces, known as "second-growth" ash. Although not relied upon for out-of-door construction, ash is one of the most important of the cheaper cabinet woods and is used in stairs, furniture, and similar works. [p028]

One half of the thirty known species of the genus Fraxinus inhabit North America. [p029]

FOOTNOTES

[Footnote 21: A tradition, old in Pliny's time, is that serpents avoid ash trees; another is that ash is particularly liable to be struck by lightning. (Keeler.)]

The name ash is also applied to several species of the genus Pyrus or Sorbus, to which the apple, pear, quince, and some other trees belong. "Mountain Ash" is either Pyrus americana or Pyrus sambucifolia. Both species, with their bright red berries, are to be classed as shrubs rather than trees; their light, soft, weak, close-grained woods having no economic importance, save perhaps for fuel. The series is partially as follows:

Pyrus malus (Common apple).
Pyrus coronaria (American crab-apple).
Pyrus communis (Common pear).
Pyrus vulgaris (Common quince).
Pyrus americana (Mountain ash).
Pyrus sambucifolia (Mountain ash).
Pyrus ancuparia (Rowan tree, European Mountain ash).

The Toothache Trees, Xanthoxylum americana and Xanthoxylum clava-herculis (Linn.), are known as ash and prickly ash. The gopher wood, Cladrastis tinctoria, is yellow ash. These woods are not important.

WHITE ASH. _Fraxinus americana Linn._

Nomenclature. (Sudworth.)

White Ash (local and common name).

Ash (Ark., Ia., Wis., Ill., Mo., Minn.).

Cane Ash (Ala., Miss., La.).

American Ash (Ia.).

Locality.

Nova Scotia to Florida, westward intermittently to Minnesota and Texas. Greatest development in the Ohio River basin.

Features of Tree.

Forty-five to ninety feet in height, occasionally higher. Three to four feet in diameter. Usually smooth leaves, have whitish under surfaces. Gray furrowed bark, long-winged seed.

Color, Appearance, or Grain of Wood.

Heartwood reddish brown, usually mottled; sapwood much lighter or nearly white. Coarse-grained, compact structure. Layers clearly marked by large open ducts. Medullary rays obscure.

Structural Qualities of Wood.

Heavy, hard, strong, elastic, becoming brittle with age, not durable in contact with soil.

Representative Uses of Wood.

Agricultural implements, carriages, handles, oars, interior and cheap cabinet-work.

Weight of Seasoned Wood in Pounds per Cubic Foot.

39 (U. S. Forestry Div.).[22]

40.

Modulus of Elasticity.

1,640,000 (average of 87 tests by U. S. Forestry Div.).[22]

1,440,000.

Modulus of Rupture.

10,800 (average of 87 tests by U. S. Forestry Div.).[22]

12,200.

Remarks.

Economically valuable. Rapid growers, preferring low, rather moist soil. Not apt to form in forests, but found mingled with other varieties. Large trees sometimes have large heart-cracks. [p030]

FOOTNOTE

[Footnote 22: See page 6.]

RED ASH. _Fraxinus pennsylvanica Marsh._ _Fraxinus pubescens Lam._

Nomenclature. (Sudworth.)

Red Ash (local and common name).

River Ash (R. I., Ont.).

Brown Ash (Mo.).

Black Ash (N. J.).

Ash (Nebr.).

Locality.

New Brunswick to Florida, westward intermittently to Dakota and Alabama. Best developed in North Atlantic States.

Features of Tree.

A small tree, rarely over forty-five feet high, one and one-half feet in diameter. Downy-covered young twigs and leaves.

Color, Appearance, or Grain of Wood.

Heartwood rich brown, sapwood light brown streaked with yellow, coarse-grained compact structure.

Structural Qualities of Wood.

Heavy, hard, strong, brittle.

Representative Uses of Wood.

Agricultural implements, handles, boats, oars, paper-pulp.

Weight of Seasoned Wood in Pounds per Cubic Foot.

38.

Modulus of Elasticity.

1,154,000.

Modulus of Rupture.

12,300.

Remarks.

Grows on borders of streams and swamps in low ground. Often confused with and substituted for the more valuable white ash. Pubescens is in allusion to the downy covering of the new twigs (those of white ash usually smooth). Pennsylvanica refers to locality in which it is well developed. [p031]

BLUE ASH. _Fraxinus quadrangulata Michx._

Nomenclature. (Sudworth.)

Blue Ash (Mich., Ill., Ky., Mo., Ala.).

Locality.

Central States, Mississippi Valley, Michigan, and southward, cultivated in Pennsylvania. Best in low Wabash Valley.

Features of Tree.

Fifty to seventy-five feet in height, occasionally higher, one to two feet in diameter. Slender. Blue properties in inner bark, smooth square twigs.

Color, Appearance, or Grain of Wood.

Heartwood light yellow, streaked with brown, sapwood lighter, close-grained, compact structure satiny.

Structural Qualities of Wood.

Hard, heavy, brittle, not strong, most durable of ash woods.

Representative Uses of Wood.

Largely used in floorings, carriage-building, pitchfork-and other tool-handles.

Weight of Seasoned Wood in Pounds per Cubic Foot.

44.

Modulus of Elasticity.

1,100,000.

Modulus of Rupture.

11,500.

Remarks.

Has no superior among ash woods. Blue Ash pitchfork-handles are very fine. Prefers limestone formations. Inner bark colors water blue, whence name. [p032]

BLACK ASH. _Fraxinus nigra Marsh._ _Fraxinus sambucifolia Lam._

Nomenclature. (Sudworth.)

Black Ash (local and common name).

Water Ash (W. Va., Tenn., Ind.).

Swamp Ash (Vt., R. I., N. Y.).

Brown Ash (N. H., Tenn.).

Hoop Ash (Vt., N. Y., Del., Ohio, Ill., Ind.).

Locality.

Northern and Northeastern States--Newfoundland to Virginia, westward intermittently to Manitoba and Arkansas.

Features of Tree.

Seventy to eighty feet in height, one to one and one-half feet in diameter. Leaves resemble those of Elder. A thin tree. Excrescences or knobs frequent on trunk. Dark, almost black, winter buds.

Color, Appearance, or Grain of Wood.

Heartwood dark brown, sapwood light brown, often nearly white, coarse-grained, compact structure, medullary rays numerous and thin.

Structural Qualities of Wood.

Separates easily in layers, rather soft and heavy, tough, elastic, not strong or durable when exposed.

Representative Uses of Wood.

Largely used for interior finish, fencing, barrel-hoops, cabinet-making, splint baskets, chair-bottoms.

Weight of Seasoned Wood in Pounds per Cubic Foot.

39.

Modulus of Elasticity.

1,230,000.

Modulus of Rupture.

11,400.

Remarks.

Excrescences known as burls; their distorted grain causes them to be prized for veneers. The most northerly of ash-trees; one of the most slender of trees. [p033]

GREEN ASH. _Fraxinus lanceolata Borkh._ _Fraxinus viridis Michx. f._

Nomenclature. (Sudworth.)

Green Ash (local and common name).

Blue Ash (Ark., Iowa).

White Ash (Kans., Neb.).

Ash (Ark., Iowa).

Swamp Ash (Fla., Ala., Tex.).

Water Ash (Iowa).

Locality.

East of Rocky Mountains. Vermont and northern Florida intermittently to Utah and Arizona.

Features of Tree.

Forty to fifty feet in height, one to two feet in diameter. Bright green upper and lower surfaces of smooth leaves.

Color, Appearance, or Grain of Wood.

Heartwood brownish, sapwood lighter, rather coarse-grained, compact structure.

Structural Qualities.

Hard, heavy, strong, brittle.

Representative Uses.

Similar to those of White Ash.

Weight of Seasoned Wood in Pounds per Cubic Foot.

39 (U. S. Forestry Div.).[23]

44.

Modulus of Elasticity.

2,050,000 (average of 10 tests by U. S. Forestry Div.).[23]

1,280,000.

Modulus of Rupture.

11,600 (average of 10 tests by U. S. Forestry Div.).[23]

12,700.

Remarks.

Sometimes considered a variety of Red Ash. [p034]

FOOTNOTE

[Footnote 23: See page 6.]

OREGON ASH. _Fraxinus Oregona Nutt._

Nomenclature.

Oregon Ash (Calif., Wash., Oregon).

Locality.

Pacific coast, Washington to California. Best developed in bottom lands, southwestern Oregon.

Features of Tree.

Fifty to occasionally seventy-five feet in height, one to one and one-half feet in diameter. Dark grayish-brown, bark exfoliates in thin scales.

Color, Appearance, or Grain of Wood.

Heartwood brown, sap wood lighter, coarse-grained, compact structure, numerous thin medullary rays.

Structural Qualities of Wood.

Rather light, hard, not strong.

Representative Uses of Wood.

Manufacture of furniture, carriage-frames, cooperage, and fuel.

Weight of Seasoned Wood in Pounds per Cubic Foot.

35.

Modulus of Elasticity.

1,200,000.

Modulus of Rupture.

9400.

Remarks.

One of the valuable deciduous trees of the Pacific coast. Thrives only on moist soils and in moist climates. [p035]

ELM. (_Ulmus_.)

The different species of elm are distributed over the cold and temperate portions of the northern hemisphere, save western United States and Canada. A high degree of perfection is attained in eastern North America, where trees are greatly prized for their form and appearance.

The foliage of the elm is concentrated at the top, and the absence of lower branches causes it to be a good tree to plant near houses or along streets. Much of the wood is tough, fibrous, durable, strong, hard, heavy, and, because it is so often cross-grained, difficult to split and work. The large pores of the spring wood arranged in one or several rows mark the annual deposit, while the minute pores of the summer wood arranged in concentric wavy lines are so peculiar as to distinguish this wood from all others. The tall, straight trunks afford pieces of considerable size. Elm piles sustain constant and severe shocks for long intervals. The grain arrangement of elm is often very beautiful, so that it is increasingly used for decoration. It is more commonly employed in the construction of cars, wagons, boats, agricultural implements, machinery, and furniture.

The shape of the trees is so marked as to cause them to be easily noted. Fifteen or sixteen species have been recognized. Five are known to exist in the eastern American forests, and all of them furnish good wood of commercial importance. _Ulmus_ was the ancient name of the elm. [p036]

FOOTNOTE

Geo. B. Emerson's "Trees and Shrubs of Massachusetts."

WHITE ELM. _Ulmus americana Linn._

Nomenclature. (Sudworth.)

White Elm (local and common name).

Water Elm (Miss., Tex., Ark., Mo., Ill., Ia., Mich., Minn., Neb.).

Elm (Mass., R. I., Conn., N. J., Pa., N. C., S. C., Ia., Wis.).

American Elm (Vt., Mass., R. I., N. Y., Del., Pa., N. C., Miss., Tex., Ill., Ohio, Kans., Neb., Mich., Minn.).

Locality.

East of Rocky Mountains, Newfoundland to Florida, westward intermittently to Dakota, Nebraska, and Texas.

Features of Tree.

Ninety to one hundred feet in height, three to seven feet in diameter. Characteristic and beautiful form, smooth buds; leaves, smaller than those of Slippery-elm, are rough only when rubbed one way.

Color, Appearance, or Grain of Wood.

Heartwood light brown, sapwood yellowish white, rather coarse-grained, annual rings clearly marked.

Structural Qualities of Wood.

Strong, tough, fibrous, difficult to split.

Representative Uses of Wood.

Flooring, wheel-stock, cooperage, ship-building, flumes, piles.

Weight of Seasoned Wood in Pounds per Cubic Foot.

34 (U. S. Forestry Division.)[24]

40.

Modulus of Elasticity.

1,540,000 (average of 18 tests by U. S. Forestry Div.).[24]

1,060,000.

Modulus of Rupture.

10,300 (average of 18 tests by U. S. Forestry Div.).[24]

12,100.

Remarks.

The concentration of foliage at top, together with the form of the tree, renders it valuable in landscape work. It does not cause dense shade. Elm and silver-maple trees are among the first to show life in spring. Discarded brownish scales then cover ground in vicinity. [p037]

FOOTNOTE

[Footnote 24: See page 6.]

CORK ELM. _Ulmus racemosa Thomas._

Nomenclature. (Sudworth.)

Cork Elm (local and common name).

Hickory Elm (Mo., Ill., Ind., Ia.).

Rock Elm (R. I., W. Va., Ky., Mo., Ill., Wis., Ia., Mich., Nebr.).

White Elm (Ont.).

Cliff Elm (Wis.).

Locality.

Quebec and Vermont, westward intermittently to Nebraska and Tennessee. Best developed in southern Ontario and Michigan.

Features of Tree.

Seventy to ninety feet in height, two to three feet in diameter. Thick, corky, irregular projections give bark a shaggy appearance and mark the species.

Color, Appearance, or Grain of Wood.

Heartwood light brown, often tinged with red; sapwood yellowish or greenish white. Compact structure, fibres interlaced.

Structural Qualities of Wood.

Heavy, hard, very strong, tough, difficult to split, susceptible of a beautiful polish, elastic.

Representative Uses of Wood.

Heavy agricultural implements, wheel-stocks, railway ties, sills, bridge-timbers, axe-helves, etc.

Weight of Seasoned Wood in Pounds per Cubic Foot.

45.

Modulus of Elasticity.

2,550,000.

Modulus of Rupture.

15,100.

Remarks.

Cork Elm is the best of the elm woods. [p038]

SLIPPERY ELM, RED ELM. _Ulmus pubescens Walt._ _Ulmus fulva Michx._

Nomenclature. (Sudworth.)

Slippery Elm, Red Elm (local and common name).

Rock Elm (Tenn.).

Redwooded Elm (Tenn.).

Moose Elm (occasional).

Locality.

Ontario and Florida, westward intermittently to Nebraska and Texas. Best developed in Western States.

Features of Tree.

Forty-five to sixty feet in height, one to two feet in diameter. Characteristic shape, mucilaginous inner bark. Buds hairy. Leaves, larger than American Elm, are rough when rubbed either way.

Color, Appearance, or Grain of Wood.

Heartwood dark brown or red, sapwood lighter, compact structure, annual layers marked by rows of large open ducts. Heartwood greatly preponderates.

Structural Qualities of Wood.

Heavy, hard, strong, and durable in contact with soil.

Representative Uses of Wood.

Largely used for fence-posts, rails, railway ties, sills, sleigh-runners, and wheel-stocks. Mucilaginous bark, employed in medicine.

Weight of Seasoned Wood in Pounds per Cubic Foot.

43.

Modulus of Elasticity.

1,300,000.

Modulus of Rupture.

12,300.

Remarks.

Mucilaginous inner bark renders this species unmistakable. This bark is used in medicine. [p039]

WING ELM, WINGED ELM. _Ulmus alata Michx._

Nomenclature.

Wing Elm, Winged Elm (local and common names).

Wahoo, Whahoo (W. Va., N. C., S. C., La., Tex., Ky., Mo.).

Cork Elm, Corky Elm (Fla., S.C., Tex.).

Mountain Elm, Red Elm (Fla., Ark.).

Elm, Witch Elm (W. Va.).

Water Elm (Ala.).

Small-leaved Elm (N. C.).

Wahoo Elm (Mo.).

Locality.

Southern United States, Virginia and Florida westward intermittently to southern Illinois and Texas.

Features of Tree.

Forty feet or more in height, one to two feet in diameter. Corky "wings" on branches.

Color, Appearance, or Grain of Wood.

Color brownish, sapwood lighter, close-grained, compact structure.

Structural Qualities of Wood.

Hard, heavy, tough.

Weight of Seasoned Wood in Pounds per Cubic Foot.

46.

Modulus of Elasticity.

740,000.

Modulus of Rupture.

10,200.

Remarks.

[p040]

MAPLE. (_Acer_.)

The maples grow on all of the continents of the northern hemisphere. Nearly one half of the known species belong in China, Japan, and the Orient. The principal European species (_Acer pseudo-platanus_) is the European sycamore.[25] The hard or sugar maple (_Acer saccharum_) is one of the principal deciduous trees of North America.

Maple wood[26] is characterized by its appearance and by its fine compact texture. The first quality is so marked that selected pieces take rank among the most beautiful of cabinet woods; the last is so pronounced as to fit it for carvings and even for type. "Birdseye," "blister," and "curly" maples are not from different species, but are the results of fibre distortions, possible in some form in any tree of any species, but peculiarly liable to occur in the maple; birdseye and blister effects for the most part in the hard maples, curly effects in the hard, but generally in the softer, species. The distortions do not occur in all trees, and it is seldom possible to tell whether the woods are thus figured until after the trees have been cut. Maple wood shrinks moderately, stands well in protected places, is strong, tough, but not durable when exposed. Pores are not arranged in circles, but are scattered irregularly throughout the layers. Maple is used for ceiling, flooring, panelling, car and ship construction, shoe-lasts, shoe-pegs, furniture, school supplies, implements, and machinery. Sugar is principally, although not exclusively, present in the sap of the sugar maple.[27] The softer species are sometimes [p041] tapped, and sugar is also present in the sap of other trees, such as the butternut and birch. A sugar maple will, on an average, produce about twenty-five gallons of sap, containing a total of about six pounds of sugar, in a season.

The Boxelder (_Acer negundo_) is a true maple, remarkable in that it is widely distributed from Canada to Mexico and from the Atlantic to the Rocky Mountains, on low bottom lands, and at elevations of five thousand and six thousand feet.[28] The trees are beautiful and, like other maples are valued for ornamental purposes. The soft, light wood is not particularly noted, although occasionally used for woodenware, interior finish, and paper-pulp. Small quantities of sugar are present in the sap of this tree.

The maples may be told by their leaves of characteristic shape, but chiefly by their two-seeded fruit or "keys," the two wings of which spread differently in different species. The leaves of some species change in autumn from green to red and other brilliant colors. Those of other species change to yellow without trace of red. Sixty to seventy species have been distinguished, nine of which occur in North America. [p042]

FOOTNOTES

[Footnote 25: See Sycamore, page 65.]

[Footnote 26: These notes apply to the American product.]

[Footnote 27: Vermont, New York, and Michigan produce the larger portion of the about fifty million pounds of sugar and three million gallons of syrup annually manufactured in the United States. Third Annual Report of the Fisheries, Game, and Forestry Commissioners, New York, 1897, p. 308.]

[Footnote 28: Sargent.]

SUGAR MAPLE, HARD MAPLE. _Acer saccharum Marsh._ _Acer saccharinum Wang._

Nomenclature. (Sudworth.)

Sugar Maple, Hard Maple (local and common names).

Black Maple (Fla., Ky., N. C.).

Sugar Tree (frequent).

Rock Maple (Me., Vt., N. H., Conn., Mass., R. I., N. Y., Tenn., Ill., Mich., Ia., Kans., Wis., Minn.).

Locality.

Best development Maine to Minnesota; range extends southward to Florida and Texas.

Features of Tree.

Seventy to one hundred feet and more in height, one and one-half to four feet in diameter. The fruit or "maple-key" with wings less than right angles ripen in early autumn; one seed-cavity is usually empty. Foliage turns to brilliant reds and other colors later. Large impressive tree.

Color, Appearance, or Grain of Wood.

Heartwood brownish, sapwood lighter, close-grained, compact structure, occasional "curly," "blister," or "birdseye" effects.

Structural Qualities of Wood.

Tough, heavy, hard, strong, susceptible of good polish, wears evenly, not durable when exposed.

Representative Uses of Wood.

Furniture, shoe-lasts, piano-actions, wooden type for showbills, pegs, interior finish, flooring, ship-keels, vehicles, fuel, veneers, rails, etc.

Weight of Seasoned Wood in Pounds per Cubic Foot.

43.

Modulus of Elasticity.

2,070,000.

Modulus of Rupture.

16,300.

Remarks.

Birdseye, blister, and to a less extent curly and landscape effects pronounced in this species. Saccharum refers to sugar manufactured from the sap. Hard maple is because of hardness of wood. [p043]

SILVER MAPLE, SOFT MAPLE. _Acer saccharinum Linn._ _Acer dasycarpum Ehr._

Nomenclature. (Sudworth.)