United StatesDepartment ofAgriculture

ForestService

AgricultureHandbookNumber 101

Wood —Colors and Kinds

CONTENTS

October 1956Approved for reprinting August 1981

For sale by the Superintendent of Documents. U.S. Government Printing OfficeWashington, D.C. 20402

WOOD—COLORS AND KINDS

Prepared by Forest Products Laboratory, Forest Service

A key element in any business transaction in-volving wood is the proper identification of species.Literally scores of different woods are bought andsold daily for hundreds of uses. A New Englandhome may be framed with Douglas-fir from Ore-gon, floored with red oak from Arkansas, sidedwith California redwood, and trimmed inside withMichigan yellow birch. Its furniture may beveneered with Pennsylvania black cherry overWisconsin basswood and fitted with drawers ofIndiana sycamore and backs of Carolina sweetgum.It is apparent that familiarity with only locallygrown species is not enough in today’s lumbermarkets.

Often, any one of several species is suitable for aspecific use. Other species, however, may be en-tirely unfit for that use. Of those suitable, someare better than others because they are stronger,perhaps, or more attractive, or hold paint better.Others may be superior because they are harder,shrink less, resist decay, or are more easily cut andjoined. It follows, then, that correct identificationis essential to insure selecting the right wood for agiven job.

As the official wood identification agency of theUnited States Government, the Forest ProductsLaboratory annually receives thousands of re-quests for identification service from industry,other branches of the Federal Government, unitsof State and local governments, and the generalpublic. This service is requested in connectionwith business transactions, civil lawsuits, criminalcases, building codes for homes and other struc-tures, industrial standards, and Government pur-chase specifications. The Laboratory has alsobeen called upon to identify wood from tombs ofEgyptian Pharaohs, sunken pirate ships, pre-historic forests, and the beam that supports theLiberty Bell.

In the great majority of day-to-day transac-tions, however, wood identification is a relativelysimple problem. By acquiring a little know-how,many lumbermen, dealers, builders, manufactur-ers, consumers, students, and home-workshop hob-byists could solve their identification problems onthe spot. Consequently, this publication was pre-pared as an aid to those persons concerned withidentifying the more common native species ofwood.

Characteristics that are apparent to the nakedeye and that distinguish our native woods fromeach other are described for each of 32 species.Because color is an important identifying char-acteristic of many woods, special attention has beenpaid to describing the natural color of a freshly cutsurface of the wood.

Descriptions of species are accompanied by full-color illustrations showing grain pattern and other

characteristics. Beginning at the top of theillustration, end-grained, edge-grained (quarter-sawed), and flat-grained (plainsawed) surfaces areall displayed. This is done because certainidentifying characteristics show up best on eachsurface. The terms “edge-grained” and “flat-grained” are used in reference to softwood lumber,while quartersawed and plainsawed refer to hard-wood lumber.

The manner in which it is sawed from the log will,of course, determine whether a piece of wood showsflat-grained or edge-grained patterns of annualgrowth rings on its wide surfaces. Lumber ismanufactured in both forms.

Each color plate presents two species. Wherepossible, closely similar species are shown togetheron one plate, so that distinguishing characteristicscan be more conveniently examined. In othercases, species are paired on one plate because theyare often marketed in mixture or used inter-changeably.

Certain species are not distinguishable fromclose relatives by the wood alone, even under themicroscope. Thus, for example, the wood of manydifferent species of red oak is identical in structureand appearance even though the trees from whichit comes may differ markedly in leaf, bark, andfruit. From the wood user’s standpoint’, however,botanical differences in trees usually do not matterso long as their wood is consistent in propertiesand appearance. Where appropriate in the de-scriptions, differences are mentioned that distin-guish a species from closely similar ones notshown. The general range of growth, properties,and common uses of each species are also given.

Obviously, many other species could have beenincluded with the 18 hardwoods and 14 softwoodsdescribed in this publication. Those chosen arethe species most commonly found in retail lumbermarkets.

To assist the reader in getting the utmost helpfrom this booklet, the terms used in the descrip-tions are defined in a glossary. These terms are incommon use among wood technologists, and thefeatures of wood to which they apply are regularlyused for identification and other purposes at theForest Products Laboratory. The common andbotanical names of species conform to the officialForest Service nomenclature for trees. Cubic-foot weights of species described are averagestaken at 12 percent moisture content; specificgravity is based on volume when green and weightwhen ovendry.

For information on botanical differences amongspecies, such as the shape of leaves, patterns ofbark, and form of fruit, the reader is referred toTrees, the 1949 Yearbook of the U. S. Departmentof Agriculture.

1

HARDWOODS (Broad-Leaved Species)

American beech (Fagus grandifolia)

Range.—The natural range of beech in theUnited States extends from Maine to northernFlorida and westward from the Atlantic coastinto Wisconsin, Missouri, and Texas. It usuallygrows in mixture with other species, althoughpure stands of considerable extent occur in theBlue Ridge Mountains,Carolina.

especially in North

Properties.— One of the heavy woods, Americanbeech has an average weight of 45 pounds a cubicfoot and, with a specific gravity of 0.56, is classi-fied as hard. It is rated high in strength andshock resistance and is readily bent when steamed.

Beech is subject to very large shrinkage andrequires considerable care during seasoning ifchecks, warp, and discoloration are to be avoided.Heartwood ranks low in resistance to decay.The wood wears well and stays smooth whensubjected to friction, even under water. Althoughranking high in nail-withdrawal resistance? ithas a tendency to split when nails are driveninto it. When pulped by the soda process, beech

yields a short-fibered pulp that can be mixed withlonger fibered pulps to obtain paper of satisfactorystrength.

Uses.—American beech is used for lumber,distilled products, veneer, railroad ties, pulpwood,cooperage, and fuel. The lumber is used largelyin the manufacture of boxes, crates, baskets,furniture, handles, flooring, woodenware, generalmillwork, and novelties. Beech is especiallysuitable for food containers, since it does notimpart taste or odor.

Description.— Heartwood is white with a red-dish tinge to reddish brown. Pores are not visi-ble but wood rays can be seen on all surfaces.On the end grain, the rays appear to be irregularlyspaced, while on quartersawed surfaces they ap-pear to be of different heights along the grain.On the plainsawed surfaces, the rays also appear tobe of different height, but they look much nar-rower in this view. Beech is readily distinguish-able from other native species by its weight, con-spicuous rays, and tiny pores. (Illustration, p. 11.)

American sycamore (Platanus occidentalis)

Range.—American sycamore grows in scatteredgroups or singly from southern Maine westwardto Nebraska and southward to eastern Texas andnorthern Florida. It grows best on flatlands wherethere is a good supply of ground water and alongthe edges of streams. lakes. and swamps. At leasthalf of the stand of American sycamore is in thecentral and southern portions of its range inAlabama, Arkansas, Indiana, Kentucky, Louisiana,Mississippi, Missouri, and Tennessee.

Properties.— In weight, American sycamore isranked as a moderately heavy wood, averaging34 pounds a cubic foot. A moderately hard wood,with a specific gravity of 0.46, it has a close textureand an interlocking grain. It is moderately strong,moderately stiff, and has moderately good shockresistance.

Sycamore has large shrinkage while drying, isinclined to warp, and is somewhat difficult toseason. Also, it is not durable when exposed toconditions favorable to decay. The wood turnswell on a lathe and keeps its shape well when bentto form after steaming. It is only intermediate innail-withdrawal resistance but because of its

interlocking grain ranks high in its ability to with-stand splitting. Sycamore wood does not imparttaste, odor, or stain to substances that come incontact with it.

Uses.-The principal uses of American syca-more are for lumber, veneer, railroad ties, cooper-age, fence posts, and fuel. The lumber goes largelyinto furniture and boxes. Considerable sycamoreveneer is used for fruit and vegetable baskets andberry boxes. Although generally used for thecheaper grades of furniture, sycamore is used inone form or another in practically all grades. Otherproducts made from the lumber include flooring,scientific instruments, handles, and butchers’blocks.

Description.— Heartwood is reddish brown orflesh brown in color. Pores are very small and notvisible to the unaided eye. Rays are visible on allsurfaces. They appear uniformly spaced on theend grain and of uniform height on quartersawedsurfaces. Plainsawed surfaces show rays thatappear more numerous and more closely spacedthan in beech. (Illustration, p. 11.)

2

Rock elm (Ulmus thomasii)

Range.—Rock elm grows from New Hampshireto Nebraska and as far south as Tennessee.Much of the commercially important rock elm islocated in Wisconsin and Michigan and morethan 80 percent of rock elm lumber and veneercomes from these 2 States.

Properties.— Rock elm is a heavy wood, averag-ing 44 pounds a cubic foot. The wood is clas-sified as hard, with a specific gravity of 0.57. Itis stronger, harder, and stiffer than any of theother commercial elms. With the exception ofhickory and dogwood, rock elm has higher shockresistance than any other American hardwood.

Uses.—Elm lumber is used principally forcontainers and furniture. In some cases, thedifferent species of elm are employed indiscrim-inately, but when hardness or shock resistance isrequired to a high degree, rock elm is preferred.Rock elm veneer is used in considerable quantitiesin manufacturing various types of containers,especially fruit and vegetable boxes and baskets.

Although rock elm undergoes large shrinkagewhen drying, it tends to shrink somewhat lessthan the other commercial elms. As with all theelms, care must be taken to prevent warp duringseasoning. Rock elm is somewhat difficult towork with hand or machine tools, and the heart-wood has low to moderate resistance to decay.However, all the commercial elms have excellentbending qualities.

Large quantities of rock elm also go intocrating for heavy articles, such as furniture, glass,and porcelain. The strength and toughness ofthis wood make it very serviceable for certaintypes of containers that must stand rough usage,such as market baskets and bushel baskets forhome use. Considerable quantities are used inthe manufacture of furniture, especially the bentparts of chairs.

Description.— Heartwood is brown to darkbrown, sometimes with shades of red. Summer-wood pores are arranged in concentric wavy linesthat appear lighter than the background wood.The springwood pores in rock elm are visibleonly upon magnification. (Illustration, p. 12.)

American elm (Ulmus americana)

Range.—American elm grows throughout theeastern United States except in the Appalachianhighlands and southern Florida. About three-fourths of the stand of sawtimber size is located inthe Lake States and the Mississippi Delta region.Wisconsin, Michigan, Louisiana, Arkansas, Ohio,and Indiana have large volumes of elm.

Properties.— American elm is moderately heavy,averaging 35 pounds a cubic foot, and moderatelyhard, with a specific gravity of 0.46. It rates asmoderately weak, but is moderately stiff and hasgood shock resistance.

The wood of American elm has large shrinkageand care must be taken to prevent warping as itseasons. Like all of the commercial elms, it hasexcellent bending qualities. Its heartwood haslow to moderate resistance to decay. The woodis slightly below average in woodworking proper-ties, but is among the top woods in ease of gluing.In nail-withdrawal resistance, it has an inter-mediate rank.

Uses.—American elm lumber is used principallyin the manufacture of containers, furniture, anddairy and poultry supplies. Because of its excel-lent bending properties, the wood has been muchused for barrels and kegs. Considerable quan-tities of veneer go into the manufacture of fruitand vegetable boxes and baskets. American elmalso is used a great deal for crating heavy articles,such as furniture, glass, and porcelain products.It is used in sizable quantities in the furnitureindustry, particularly for the bent parts of chairs.

Description.— Heartwood is brown to darkbrown, sometimes containing shades of red.Although the summerwood pores are not visibleas individuals, they are arranged in concentricwavy lines within the boundaries of the growthrings. The wavy lines appear lighter than thebackground wood. American elm shows a spring-wood pore zone with a single row of large andeasily visible pores. (Illustration, p. 12.)

3

Black walnut (Juglans nigra)

Range.—Black walnut grows naturally over alarge area extending from Vermont westward toNebraska and southward to southern Georgia andsouthern Texas. The area of greatest commercialproduction is limited to the central part of thisnatural range.

Properties.—Black walnut is classified as aheavy wood, averaging 38 pounds a cubic foot.The wood is hard, with a specific gravity of 0.51,is strong and stiff, and has good shock resistance.

Even under conditions favorable to decay, blackwalnut heartwood is one of our most durablewoods. It can be satisfactorily kiln-dried or air-dried, and holds its shape well after seasoning.Black walnut works easily with handtools and hasexcellent machining properties. The wood finishesbeautifully with a handsome grain pattern. Ittakes and holds paints and stains exceptionallywell, can be readily polished, and can be satis-factorily glued.

Uses.—The outstanding use of black walnut isfor furniture. Large amounts are also used forgunstocks and interior finish, while smaller quan-tities go into railroad tics, fence posts, and fuel-wood. In the furniture industry, it is used eitheras solid wood cut from lumber or as veneer andplywood. It also is extremely popular for interiorfinish wherever striking effects are desired. Thewood of black walnut is particularly suitable forgunstocks because of its ability to stay in shapeafter seasoning, its fine machining properties, andits uniformity of texture.

Description.— Heartwood is chocolate brownand occasionally has darker, sometimes purplish,streaks. Unless bleached or otherwise modified,black walnut is not easily confused with any othernative species. Pores are barely visible on the endgrain but are quite easily seen as darker streaksor grooves on longitudinal surfaces. Arrangementof pores is similar to that in the hickories andpersimmon, but the pores are smaller in size.(Illustration, p. 13.)

Black cherry (Prunus serotina)

Range.—Black cherry’s natural growth range isthroughout Maine westward to eastern NorthDakota and southward to central areas of Floridaand Texas. It also occurs in the mountain rangesof western Texas. The largest supplies of blackcherry are believed to be located in the Appalach-ian Mountains in New York, Pennsylvania, andWest Virginia.

Properties.—Black cherry is a moderatelyheavy wood with an average weight of 35 poundsa cubic foot. The wood is also moderately hard,with a specific gravity of 0.47. Stiff and strong,it ranks high in resistance to shock.

Although it has moderately large shrinkage,black cherry stays in place well after seasoningand is comparatively free from checking andwarping. It has moderate resistance to decay.The wood is difficult to work with handtools butranks high in bending strength. It can be gluedsatisfactorily with moderate care.

Uses.—Nearly all the black cherry cut is sawed

into lumber for various products. Much goes intofurniture and considerable amounts are used forbacking blocks on which electrotype plates, usedin printing, are mounted. Other uses includeburial caskets, woodenware and novelties, patternsand flasks for metalworking, plumbers’ woodwork,and finish in buildings and railway coaches.

Description.— Black cherry, which is not easilyconfused with other native species because of itsdistinctive color, has light to dark reddish brownheartwood. Although individual pores are notvisible to the naked eye, their pattern is some-times distinctive. On end-grain surfaces, thepores may appear to form lines that parallel thegrowth rings, while on plainsawed surfaces, theymay follow the outline of the growth-ring boundary.

The wood rays of cherry are barely visible onend-grain surfaces and tend to produce a distinc-tive flake pattern on true quartersawed surfaces.They are higher along the grain than those ofwalnut and hence show more prominently onquartersawed surfaces. (Illustration, p. 13.)

4

Hickory (Carya)

Species names.—True hickories: shagbark hick-ory (Carya ovata), shellbark hickory (C. laciniosa),pignut hickory (C. glabra), and mockernut hickory(C. tomentosa) .

Range.—The true hickories grow throughoutmost of the eastern United States except innorthern New England, the northern portions ofMichigan and Wisconsm, and southern Florida.Close to 40 percent of the total stand of truehickory is located in the lower Mississippi Valleyregion.

Properties.— The wood of the true hickories isvery heavy, averaging from 42 to 52 pounds percubic foot, and very hard, with a specific gravityranging from 0.56 to 0.66. It also is very strongas a post or beam, very stiff, and exceedingly highin shock resistance. Some woods are strongerthan hickory and others are harder, but the com-bination of strength, toughness, hardness, andstiffness possessed by hickory has not been foundto the same degree in any other commercial wood.

Hickory has very large shrinkage and mustbe carefully dried to avoid checking, warping,and other seasoning defects. It has low decayresistance but can be glued satisfactorily.

Uses.—Nearly 80 percent of the true hickoryused in the manufacture of wood products goesinto tool handles, for which its hardness, tough-ness, stiffness, and strength make it especially suit-able. Other uses include agricultural imple-ments, athletic goods, and lawn furniture.

Description.— Heartwood is brown to reddishbrown. Pores are visibly, but the zone of largepores is not sharply outlined as in oak and ash.Pores grade in size from one side of the annualring to the other. Wood rays are very small andseen without magnification only on quartersawedsurfaces. Tyloses frequently plug the pores,making their outlines indistinct. Under mag-nification, the end grain shows numerous white

p. 14.)lines paralleling the growth ring. (Illustration,

White ash (Fraxinus americana)

Range.—White ash grows throughout the entireeastern half of the United States except along theAtlantic Coastal Plain, the gulf coast, and Florida.It is cut commercially everywhere except in theextreme outer limits of this range and the lowerMississippi Valley.

Properties.— White ash is a heavy wood withan average weight of 42 pounds a cubic foot.Ranked as a hard wood, it has a specific gravityof 0.55. It also is classified as strong and stiff,and has good shock resistance.

The wood of white ash is noted for its excellentbending qualities. In ease of working, tendencyto split, and ability to hold nails and screws, ithas moderately high rank. White ash lumbercan be rapidly and satisfactorily kiln-dried, andit holds its shape well even under the action ofwater. The wood remains smooth under con-tinual rubbing but is low in decay resistance.

Uses.—The use of white ash that dwarfs allothers is its utilization for handles. It is thestandard wood for D-handles for shovels andspades and for long handles for forks, hoes, rakes,

and shovels. The wood is used too in the manu-facture of furniture, where it is especially valuablefor the bent parts of chairs. Its good bendingqualities also make it useful for cooperage. Whiteash is used almost exclusively for many types ofsports and athletic equipment, such as long oarsand baseball bats.

Description.—Heartwood is brown to darkbrown, sometimes with a reddish tint. As inblack ash, the zone of large pores is visible andusually sharply defined. The white dots or linesthat indicate summerwood pores are usuallymore prominent in white than in black ash.The small wood rays are generally visible onlyon quartersawed surfaces.

White ash is sometimes confused with hickory,but the two species are readily distinguishable.The zone of large pores is more distinctive inash than in hickory. Also, the summerwoodzone in ash shows white dots or lines that arevisible to the unaided eye, but in hickory thesedots or lines are visible only upon magnification.(Illustration, p. 14.)

5

Quaking aspen (Populus tremuloides)

Range.—Quaking aspen grows throughout mostof the northeastern and western United States.The eastern part of its range extends from Mainesouthward to Tennessee and westward to theDakotas. It is also found throughout the westernUnited States except in the extreme Southwest.Commercial stands of aspen are located principallyin the Lake States and the Northeast, with smalleramounts in the central Rocky Mountain region.

Properties.— One of the lightweight hardwoods,quaking aspen averages 26 pounds a cubic foot.The wood is classified as soft, with a specific grav-ity of 0.35, and is weak, limber! and moderatelylow in shock resistance.

Although aspen has moderately large shrinkage,it can be seasoned satisfactorily by air-drying orkiln-drying. In fact, few of the hardwoods shrinkas little as aspen. The wood ranks low in decayresistance. It also is low in nail-withdrawal resist-ance, but has little tendency to split under theaction of nails or screws. It is worked easily withhand or power tools and is fairly easy to finish to a

smooth surface. Aspen glues easily with a varietyof glues and under a wide range of gluing condi-tions. In painting properties, it ranks with thebest of the hardwoods.

Uses.—Aspen is used principally for lumber,paper pulp, excelsior, and matches. The largestpresent-day use of the lumber is for boxes andcrates. It is probably most heavily used for pulp-wood, chiefly in the manufacture of book andmagazine paper and corrugating and insulatingboards. Aspen has long been one of the preferredwoods for the manufacture of high-grade excelsior.

Description.—Heartwood is white to very lightbrown, with occasional brown streaks associatedwith defects. Pores are very small and generallynot visible to the unaided eye. Growth rings areusually faint. Wood rays are small, uniform inheight along the grain, and visible only on quarter-sawed surfaces. Aspen is similar to cottonwood,but cottonwood tends to have barely visible pores.The growth rings in aspen are generally narrowerthan those in cottonwood. (Illustration, p. 15.)

American basswood (Tilia americana)

Range.—Basswood grows throughout the east-ern half of the United States from Maine westwardto North Dakota and southward to Florida andeastern Texas. More than half of the total standis located in the Lake States, and another quarteris in the east central part of the range.

Properties.— Basswood is a lightweight hard-wood with an average weight of 26 pounds a cubicfoot. The wood is weak, moderately stiff, and lowin resistance to shock. Its specific gravity of 0.32classes it as soft.

Although it has large shrinkage, basswood isfairly easy to air-dry or kiln-dry and stays in placewell after seasoning. It has low nail-withdrawalresistance, but. well resists splitting while beingnailed. In decay resistance, it is low. The woodis easy to work with tools, takes and holds paintwell, and is easily-glued. When pulped by the sodaprocess, basswood yields a soft, short-fibered, easilybleached pulp.

Uses.—Most of the basswood cut in this countryis first made into lumber for a variety of items.The largest amounts are used for crates and boxes.The manufacture of sash, doors, and general mill-work also accounts for much of the basswoodlumber produced each year. In addition consider-able lumber and veneer is used in the furnitureindustry, especially as core material overlaid withhigh-grade furniture veneers, such as walnut andmahogany.

Description.— Heartwood is creamy white tocreamy brown or sometimes reddish. Pores arevery small, as in aspen, and growth rings on plain-sawed surfaces are generally faint. Wood rays arebroader and higher than in aspen, and the twospecies can be readily distinguished by comparingtheir quartersawed faces. While the rays of aspenare low and uniform in height, some of those inbasswood are distinctly higher than others andfrequently darker than the background wood.(Illustration, p. 15.)

6

Range.—Sweetgum grows from southwesternConnecticut westward almost to Kansas andsouthward to eastern Texas and central Florida.The commercial range in the United States isconfined largely to the moist lands of the lowerOhio and Mississippi Basins and to the lowlandsof the southeastern coast.

Properties.— Sweetgum is a moderately heavywood with an average weight of 36 pounds percubic foot. The wood is hard, with a specificgravity of 0.46, moderately strong when used asa beam or post, moderately stiff, and has moder-ately high shock resistance.

Sweetgum has very large shrinkage in drying,and the sapwood and heartwood require differentdrying processes. The heartwood has low tomoderate decay resistance. In nail-holding abilityand in ability to resist splitting by nails and screws,sweetgum is rated intermediate. The heartwoodrequires special treatment before gluing can bedone with best results.

Sweetgum (Liquidambar styraciflua)

Sweetgum ranks above average in turning,boring, and steam-bending properties but some-what below average in the other machining prop-erties. Its heartwood can be finished in a widevariety of color effects and the sapwood can bereadily stained if a darker color is desired.

Uses.-The principal uses of sweetgum are forlumber, veneer, plywood, and slack cooperage.The lumber goes principally into boxes and crates,furniture, interior trim, and millwork. Veneer isused mainly for boxes, crates, baskets, furniture,and interior woodwork. Some sweetgum is usedfor crossties and fuel, and comparatively smallamounts go into fencing, excelsior, and pulpwood.

Description.—Heartwood is reddish brown andoccasionally variegated with streaks of darkercolor. Pores are so small that they are notvisible except upon magnification. Growth ringsare usually indistinct or inconspicuous. Raysare visible on quartersawed faces. (Illustration,p. 16.)

Black tupelo (Nyssa sylvatica)

Range.-Black tupelo grows in all States eastof the Mississippi River and as far west as centralTexas in the southern part of its range. In thenorthern and eastern parts of its range, it growsunder a wide variety of conditions ranging fromswamps to dry mountainsides, but in the Southit is largely confined to well-drained locations.The largest commercial cuts of black tupelolumber are made in the Southeastern States.

Properties.— A moderately heavy wood, blacktupelo has an average weight of 35 pounds a cubicfoot. It is rated as hard, with a specific gravityof 0.46, and the heartwood is low to moderate inresistance to decay. The wood is moderately weakwhen used as a beam or post, moderately limber,and moderately high in ability to resist shock.

Black tupelo has large shrinkage and a tendencyto warp while seasoning because of its interlockinggrain. Considerable care is required in the dryingprocess to produce straight, flat lumber. The

wood generally requires special treatment beforegluing to obtain the best results and it ranks belowthe average of 25 southern hardwoods in machin-ing properties. In nail-withdrawal resistance andresistance to splitting under the action of nails,black tupelo has an intermediate rank. It can bereadily pulped by the chemical and semichemicalprocesses.

Uses.—Black tupelo is used mainly for lumber,veneer, and paper pulp, and to some extent forrailway ties and cooperage. The lumber goeslargely into shipping containers and furniture.Black tupelo has been used for many years in themanufacture of book and similar grades of paper.

Description.—Heartwood is pale to moderatelydark brownish gray or dirty gray. Pores are verysmall, as in sweetgum. Growth rings are generallyinconspicuous to moderately distinct. Rays arevisible on quartersawed surfaces, but show up lessprominently against the background color of thewood than the rays in sweetgum. (Illustration,p. 16.)

7

White oak (Quercus)

Species names.—The white oak group includeswhite oak (Quercus alba), chestnut oak (Q. prinus),post oak (Q. stellata), overcup oak (Q. lyrata),swamp chestnut oak (Q. michauxii), bur oak(Q. macrocarpa), chinkapin oak (Q. muehlenbergii),swamp white oak (Q. bicolor), and live oak(Q. virginiana).

Range.—White oaks grow mainly in theeastern half of the United States, although somespecies are found as far west as eastern Oregon,Washington, and California. Commercial whiteoaks grow east of a line from western Minnesotato western Texas.

Properties.— The white oaks are heavy woods,averaging 47 pounds a cubic foot, and are veryhard, with a specific gravity ranging from 0.57 inchestnut oak to 0.81 in live oak. Led by liveoak, they rank high in strength properties.

The wood of the white oaks is subject to largeshrinkage and seasoning must be done carefullyto avoid checking and warping. Pores of theheartwood, with the exception of chestnut oak,are usually plugged with tyloses, a frothlikegrowth that makes the wood impervious to

liquids. The heartwood itself is comparativelydecay resistant, generally more so than that ofthe red oaks. White oaks are above average inall machining operations except shaping.

Uses.—Most white oak is made into lumberfor flooring, furniture, general millwork, and boxesand crates. Large amounts are used for flooringand furniture and it is the outstanding wood fortight barrels, kegs, and casks because of thenonporous heartwood. It has long been theleading wood for the construction of ships andb o a t s .

Description.— Heartwood is grayish brown.The outlines of the larger pores are indistinctexcept in chestnut oak, which has open poreswith distinct outlines. On smooth-cut, end-grainsurfaces, the summerwood pores are not distinctas individuals. Wood rays are generally higherthan in red oak, the larger ones ranging from ½ to5 inches in height along the grain. As in redoak, rays appear lighter in color than the back-ground wood on end-grain surfaces and darkerthan the background wood on side-grain surfaces.(Illustration, p. 17.)

Red oak (Quercus)

Species names.—The red oak group includesnorthern red oak (Quercus rubra), black oak (Q.velutina ), scarlet oak (Q. coccinea), shumard oak(Q. shumardii), pin oak (Q. palustris), Nuttall oak(Q. nuttallii), southern red oak (Q. falcata), wateroak (Q. nigra), laurel oak (Q. laurifolia), andwillow oak (Q. phellos) .

Range.—Red oaks grow quite generally east ofthe Great Plains except for a narrow coastal stripalong the Gulf of Mexico and in Florida. Thelargest amounts of commercial timber are cut inTennessee, Arkansas, Kentucky, and Missouri.

Properties.—The red oaks are similar in manyproperties to the white oaks. A major differenceis that red oak, because it lacks tyloses in itspores, is extremely porous. A heavy wood, itaverages 44 pounds a cubic foot and the averagespecific gravity of the more important speciesranges from 0.52 to 0.60. The wood is hard, stiff,and has high shock resistance.

Red oak undergoes large shrinkage while drying,and seasoning must be done carefully to avoidchecking and warping. It is considerably above

average in all machining operations except shap-ing, and the heartwood ranks low to moderate indecay resistance.

Uses.—Most of the red oak cut in this countryis converted into flooring, furniture, millwork,boxes and crates, caskets and coffins, agriculturalimplements, boats, and woodenware. Consider-able lumber is also used in building construction,and some is exported. The hardness and wearingqualities of red oak have made it an importantflooring wood for residences. Preservative-treatedred oak is used extensively for crossties, minetimbers, and fence posts.

Description.—Heartwood is grayish brown witha more or less distinctive reddish tint. Pores arecommonly open, and the outlines of the largerpores are distinct. On smoothly cut end-grainsurfaces, the summerwood pores can be seen asindividuals and readily counted when examinedwith a hand lens. Wood rays are commonly¼ to 1 inch high along the gram. On end-grainsurfaces, rays appear as lines crossing the growthrings. (Illustration, p. 17.)

8

Range.—Yellow birch grows in the Lake States,New England, New York, New Jersey, Pennsyl-vania, and along, the Appalachian Mountains intosouthern Georgia. It reaches its best developmentnear the Canadian border, and more than half ofthe stand is located in Michigan. The largestamounts of lumber are produced in Michigan andWisconsin.

Properties.— Yellow birch is heavy, averaging43 pounds a cubic foot, and hard, with specificgravity averaging 0.55. The wood is strong, stiff,and has very high shock resistance.

Yellow birch has very large shrinkage and mustbe seasoned carefully to prevent checking andwarping. Like all commercial birches, it is low indecay resistance. Although the wood is difficultto work with handtools, it can be readily shaped bymachine and ranks high in nail-withdrawal re-sistance.

Uses.—Yellow birch is used principally forlumber, veneer, distilled products, and crossties.

Yellow birch (Betula alleghaniensis)

The lumber and veneer go mostly into furniture,boxes, baskets, crates, woodenware, interior finish,and general millwork. It is because of its pleasinggrain pattern and ability to take a high polish, thatyellow birch is widely used in the furniture in-dustry. Spools, bobbins, and other turned articlesare also important products.

Yellow birch is one of the principal woods usedfor hardwood distillation to produce wood alcohol,acetate of lime, charcoal, tar, and oils. It is usedin smaller quantities for pulpwood and cooperage.

Description.— Yellow birch heartwood is lightreddish brown. Pores are very small, sometimesjust barely visible on smoothly cut end-grainsurfaces, and are uniformly distributed throughthe annual ring cross section. Pore lines are visibleon longitudinal surfaces as very fine grooves thatmay even be seen through natural finishes. Woodrays may be seen only on quartersawed surfaces,where they appear to be of one size and of uniformheight along the grain. Growth rings are moder-ately distinct on plainsawed surfaces. (Illustration,p. 18.)

Sugar maple (Acer saccharum)

Range.-Sugar maple grows from Maine toMinnesota and southward to eastern Texas andnorthern Mississippi, Alabama, and Georgia.The largest stands are in the Lake States and theNortheast. The tree grows singly or in groupsin mixed stands of hardwoods.

Properties.— Sugar maple is heavy, averaging44 pounds a cubic foot, and hard, with a specificgravity of 0.56. Strong and stiff, it has highresistance to shock. Although it has large shrink-age and presents some difficulties in drying, thewood can be satisfactorily seasoned. Its resist-ance to decay is low to moderate.

Sugar maple ranks high in nail-withdrawalresistance and intermediate in ease of gluing.The wood takes stain satisfactorily and is capableof a high polish. Although generally straight-grained, sugar maple occasionally occurs withcurly, wavy, or bird’s-eye grain. The wood turnswell on a lathe, is markedly resistant to abrasivewear, and is without characteristic taste or odor.

Uses.—Sugar maple is used principally forlumber, distilled products, veneer, crossties, andpaper pulp. Probably 90 percent of the lumberis manufactured into such products as flooring,furniture, boxes and crates, handles, woodenware,and novelties. It is especially suitable for bowlingalleys, dance floors, and other flooring that issubjected to hard use. Sugar maple is one of theprincipal woods used in the hardwood distillationindustry for the production of charcoal, aceticacid, and wood alcohol.

Description.—Heartwood is light reddish brownand sometimes shows greenish-black streaks nearinjuries. Pores are extremely small and not visi-ble on any surface. Wood rays may be seen onthe end grain and especially on quartersawedfaces, where the higher rays are distinctivebecause of their color and size and smaller raysappear as fine lines between them. The woodrays may also be seen on plainsawed surfaces asvery small darker colored flecks that are parallelto the grain of the wood. (Illustration, p. 18.)

9

Yellow-poplar (Liriodendron tulipifera)

Range.-Yellow-poplar grows in all the Stateseast of the Mississippi River except Maine, NewHampshire, Vermont, and Wisconsin, and in partsof Oklahoma and Missouri. Virginia, NorthCarolina, South Carolina, Georgia, and Alabamacontain more than half of the yellow-poplar saw-timber in the United States.

Properties.— Moderately light in weight, yel-low-poplar averages 30 pounds a cubic foot. Thewood is classed as moderately soft, with a specificgravity of 0.40, and is moderately low in bendingand compressive strength, moderately stiff, andmoderately low in shock resistance. Although itundergoes moderately large shrinkage when driedfrom a green condition, it is not difficult to seasonand stays in place well when seasoned. The heart-wood is low to moderate in resistance to decay.

Yellow-poplar ranks intermediate in machiningproperties. Although low in nail-withdrawalresistance, it has little tendency to split whennailed. Also, the wood has an excellent reputation

Cottonwood

Species names.—Eastern cottonwood (Populusdeltoides ), swamp cottonwood (P. heterophylla),and black cottonwood (P. trichocarpa).

Range.—Eastern and swamp cottonwood growin small scattered stands or in mixture with otherspecies. They range from southern New Englandwestward to the southern part of the Lake Statesand southward to northern Florida and easternTexas, except in the Appalachian highlands fromNew York to Georgia and in the Ozark Mountainsof Arkansas and Missouri. Black cottonwoodgrows in the Pacific Coast States and in westernMontana, northern Idaho, and western Nevada.

Properties.— The cottonwoods are moderatelylight in weight, ranging from 24 to 28 pounds acubic foot. With a specific gravity of 0.37,eastern cottonwood is classified as moderatelysoft, while black cottonwood’s specific gravity of0.32 classifies it as soft. The cottonwoods aremoderately weak in bending and compression,moderately limber, and moderately low in shockresistance.

Moderately large shrinkage is a characteristicof cottonwood and it requires careful seasoning if

for taking and holding paint, enamel, and stainand can be glued satisfactorily. Yellow-poplarcontainers do not impart taste or odor to food-stuffs, and the wood can be easily pulped by thechemical and semichemical processes.

Uses.—The principal uses of yellow-poplar arefor lumber, veneer, and pulpwood. The lumbergoes mostly into furniture, boxes and crates,interior finish, siding, fixtures, and musical instru-ments. The veneer is used extensively for finish,furniture, and various forms of cabinetwork.

Description.—Heartwood is brownish yellow,usually with a definite greenish tinge. The woodrays, as seen on a smoothly cut end-grain surface,are somewhat more prominent than in cucumber-tree. Positive identification of yellow-poplar andcucumbertree is best accomplished microscopically,but it is possible to separate them on the basis ofgross features when both woods are at hand.(Illustration, p. 19.)

(Populus)

warp is to be avoided. The heartwood has lowdecay resistance and the wood is rather difficultto work with tools without producing chipped orfuzzy grain. Cottonwood is low in nail-with-drawal resistance but does not, split easily whennailed. The wood is classed among those thatglue satisfactorily with moderate care. It has agood reputation for holding paint.

Uses.—A large proportion of the annual outputof cottonwood is cut into lumber and veneer andthen remanufactured into containers and furniture.Both lumber and veneer are used in the furnitureindustry for core material, which is overlaid withhigh-grade furniture veneers.

Description.— Heartwood of all three cotton-wood species is grayish white to light grayishbrown with occasional streaks of light brown.The annual rings are rather wide. Pores arebarely visible on smooth cut, end-grain surfaces.Aside from the color of the heartwood, cottonwoodis extremely similar to black willow. Separationof the two species is based mainly on heartwoodcolor, which is light brown or reddish brown inwillow, or on microscopic examination if onlysapwood material is available. (Illustration, p. 19.)

10

American beech American sycamore

11

Rock elm

12

American elm

Black walnut Black cherry

13

14

True hickory White ash

Quaking aspen Basswood

15

Sweetgum Black tupelo

16

White oak Red oak

17

Yellow birch Sugar maple

18

Yellow-poplar Eastern cottonwood

19

Baldcypress Redwood

20

Incense-cedar Western redcedar

21

Sitka spruce Engelmann spruce

23

Sugar pine Western white pine

24

Western larch Douglas-fir

25

Western hemlock White fir

26

SOFTWOODS (Cone-Bearing Species)

Baldcypress (Taxodium distichum)

Range.—Baldcypress grows along the AtlanticCoastal Plain from Delaware to Florida and west-ward along the gulf coast nearly to the Mexicanborder in Texas and up the Mississippi Valley tosouthern Indiana. The heaviest stands occur inthe swamps of the lower Mississippi Valley and

building construction, especially where decayresistance is required. It is frequently used forposts, beams, and other members in warehouses,docks, factories, and bridges. Because of its highdegree of resistance to decay, it is particularlyvaluable for greenhouses, stadium seats, coolingtowers, and roof planks of dye houses.Florida.

Properties.— Baldcypress is moderately heavy,with an average weight of 32 pounds a cubic foot,and moderately hard, with a specific gravity of0.42. The wood is also moderately strong andmoderately stiff. Its durability under conditionsfavorable to decay is outstanding.

Since green baldcypress lumber contains con-siderable moisture, it requires more care and timeto kiln-dry than many other softwoods. However,the wood has moderately small shrinkage andslow air-drying is successfully practiced. It doesnot impart taste, odor, or color to food products.

Uses.—The principal use of baldcypress is in

Cypress is also used extensively for caskets andburial boxes and for sash, doors, blinds, interiortrim and paneling, and general millwork. Con-tainers, such as boxes, crates, vats, tanks, andtubs, require considerable quantities.

Description.—Heartwood varies in color frompale brown to blackish brown and sometimes hasa reddish tinge. The wood is without resin canals,and transition from springwood to summerwoodis abrupt, as in redwood. Heartwood of darkerspecimens generally has a more or less rancid odorand longitudinal surfaces feel distinctly greasyor waxy. (Illustration, p. 20.)

Redwood (Sequoia sempervirens)

Range.— Redwood grows along or near the coastof California in a narrow, irregular strip not morethan 35 miles wide and about 500 miles long, ex-tending from 100 miles south of San Francisco to alittle above the Oregon border. This massive treedoes not grow naturally outside this area, which ischaracterized by frequent fogs and considerablesoil moisture. Single acres of redwood have beenfound that contained over 1 million board-feet of

seasoning. Redwood has only intermediate nail-withdrawal resistance but takes and holds paintexceptionally well. Redwood, the cedars, andbaldcypress make up the group of woods with thehighest resistance to termites.

Uses.—Probably from one-half to two-thirds ofthe redwood lumber produced is used in the formof planks, dimension, boards, joists, and posts. Alarge part of this material goes into framing forhouses and industrial buildings, and into bridges,trestles, and other heavy construction. Much ofthe remaining lumber is remanufactured into housesiding, sash, blinds, doors, general millwork, out-door furniture, and tanks. Richly colored red-wood paneling provides pleasing interior effects.

lumber.Properties.— Typical virgin-growth redwood is

moderately light in weight, averaging 28 pounds acubic foot: The wood is moderately hard, with aspecific gravity of 0.38, moderately strong, andmoderately stiff. Except for shock resistance, ithas somewhat higher strength properties for itsweight than would be expected.

Redwood is thought to owe its outstanding decayresistance to the reddish extractive in the tree,which colors the wood and accounts for its name.The wood has very small shrinkage, is compara-tively easy to season, and holds its shape well after

Description.— Heartwood is usually a uniformdeep reddish brown. The wood is without resincanals and has no distinctive odor, taste, or feel.Western redcedar may approach redwood in color,but the distinctive odor of western redcedar sepa-rates the two woods immediately. (Illustration,p. 20.)

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Incense-cedar (Libocedrus decurrens)

Range.—Incense-cedar grows from southwest-ern Oregon southward through California in toMexico and Lower California, with some smallstands in western Nevada. Most of the com-mercial cut is confined to the Sierra NevadaMountains in California and the mountain regionsof northern California and southern Oregon.

Properties.— A lightweight wood, incense-cedaraverages 26 pounds per cubic foot. The wood ismoderately soft, with a specific gravity of 0.35,moderately weak, limber, and low in shockresistance.

Incense-cedar has small shrinkage and is com-paratively easy to season with little checkingor warping. It ranks among the most decay-resistant woods, along with cypress, redwood, andblack locust. Also, the wood splits readily andevenly. and is easy to work with tools. Incense-cedar is one of the woods that holds paint longestand suffers least when protection against weather-ing becomes inadequate.

Uses.—The principal uses of incense-cedarare for lumber, fence posts, and crossties. Nearly

Western redcedar (Thuja plicata)

Range.—Western redcedar grows in a belt alongthe western coast of North America from southernAlaska to northern California. From northernWashington the range extends as far inland asMontana and then spreads a limited distancenorth and south on the western slopes of theRocky Mountains. More than two-thirds ofthe stand of sawtimber is located in the coastlowlands of Washington.

Properties.— Western redcedar is light in weight,averaging 23 pounds a cubic foot. The wood ismoderately soft, with a specific gravity of 0.31,weak as a beam or post, moderately limber, andlow in ability to resist shock. In decay resistance,the heartwood ranks with the more durable woods.

The wood of western redcedar is not difficultto kiIn-dry when proper methods are used, butrequires more care in seasoning than other westerncedars. After it, has been properly dried, it staysin place well and has little tendency to warp.It is comparatively low in nail-withdrawal resist-ance but can be easily glued. Western redcedar

all the high-grade lumber is used in the manu-facture of pencils and venetian blinds. Sincemost incense-cedar lumber is more or less pecky,it is used locally for rough construction. Thequalities of incense-cedar that adapt it particularlyto pencil manufacture are straightness of grain,softness, and ease of whittling. Its decay re-sistance makes it well suited for fence posts andcrossties.

Description.—Heartwood is reddish brown todull brown, with an occasional tinge of lavender.Heartwood has a characteristic cedarlike odorand acrid taste. Shavings placed on the tonguefor a few seconds give a slight burning sensation.Transition from springwood to summerwood ismore or less abrupt and makes the growth ringsprominent on flat-grained surfaces. It is easierto produce a smooth cut on the end grain ofincense-cedar than on western redcedar. Al-though incense-cedar and western redcednr cannotalways be separated with certainty on the basisof gross features, they can be readily distinguishedunder the microscope. (Illustration, p. 21.)

takes and holds paint very well and is exceptionallyweather resistant.

Uses.—The principal uses of western redcedarare for shingles, lumber, poles, posts, and piling.The lumber goes largely into exterior siding forhouses, interior finish, greenhouse construction,flumes, and structural timbers, with smalleramounts being used in the manufacture of shipsand boats, caskets, boxes and crating, sash, doors,and general millwork. Round western redcedarpoles, most of which are treated with a preserva-tive, are shipped to all parts of the United Statesfor use as utility poles.

Description.—Heartwood is reddish or pinkishbrown to dull brown. It has a characteristiccedarlike odor, but shavings placed on the tonguedo not give quite the sensation that incense-cedarshavings do. Transition from springwood tosummerwood is the same as in incense-cedar.The wood is sometimes confused with redwood, butthe cedarlike odor of western redcedar separatesthe two species immediately. (Illustration, p. 21.)

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Shortleaf pine (Pinus echinata)

Range.—Shortleaf pine, which has the widestdistribution of the southern pines, grows through-out most of the southeastern United States. It isgenerally a tree of the uplands and foothills, butits range extends into the lower levels. Stands ofshortleaf pine are concentrated in Arkansas, butTexas, Georgia, Alabama, and Mississippi alsocontain large stands.

Properties.— Shortleaf pine, a moderately heavywood but, ranking with the lightest of the im-portant southern pines, has an average weight of36 pounds a cubic foot. Typically, the wood ismoderately hard, with a specific gravity of 0.46,moderately strong, stiff, and moderately shockresistant. The heartwood is moderately decayresistant.

Like all southern pines, shortleaf has moderatelylarge shrinkage but tends to stay in place wellafter seasoning. In nail-withdrawal resistance, itranks above hemlock, spruce, and Douglas-fir.And, like other southern pines, it produces aresinous substance from which turpentine androsin can be made.

Ponderosa pine

Range.-Ponderosa pine grows in every Statewest, of the Great Plains, with the largest standsand greatest commercial production in California,Oregon, and Washington. The tree is found on awide variety of soils, sites, and elevations andoccurs both in pure stands and in mixture withother species. Because it can maintain itself ondry sites, this tree is the principal species on areasof low rainfall.

Properties.— The wood of Ponderosa pine variesconsiderably in its properties. However, in theouter portions of trees of sawtimber size, it gen-erally is moderately light in weight, averaging 28pounds per cubic foot, and moderately soft, witha specific gravity of 0.38. This wood also ranksas moderately weak, moderately limber, and mod-erately low in shock resistance. It has moderatelysmall shrinkage and little tendency to warp.

Ponderosa pine compares favorably with woodsof similar density in nail-withdrawal resistance, isnot easily split by nails, and glues easily. Theheartwood has low to moderate decay resistance.

Uses.—Shortleaf pine lumber is used prin-cipally for building material such as interior finish,ceiling, frames, sash, sheathing, subflooring, andjoists, and for boxes and crates, caskets, furniture,woodenware, and novelties. Considerable use isalso made of shortleaf pine for crossties, telephoneand telegraph poles, and mine timbers. In addi-tion, the resin-rich heartwood is distilled to makewood turpentine, tar, and tar oils. Large amountsof this southern pine are used for paper pulp.

Description.— Heartwood ranges from shadesof yellow and orange to reddish brown or lightbrown. Transition from springwood to summer-wood is abrupt, with the annual rings prominenton all surfaces. Resin canals are large and abund-ant and are easily found in all annual rings.Summerwood bands are generally wider thanthose of ponderosa pine. In appearance, the woodof shortleaf pine closely resembles that of long-leaf, loblolly, and slash, the other principalsouthern pines. (Illustration, p. 22.)

(Pinus Ponderosa)

Uses.—Ponderosa pine is used principally forlumber and, to a lesser extent, for piling, poles,posts, mine timbers, veneer, and hewn ties. Thelumber has a variety of uses ranging from high-grade millwork to boxes and crates. For cabinetsand millwork, the clearer, softer material is used,while the manufacture of boxes and crates con-sumes the lower grade lumber. Knotty ponderosapine has come into wide use as paneling for interiorfinish.

Description.—Heartwood is yellowish to light red-dish or orange brown. Transition from springwoodto summerwood is abrupt as in the southern pines,but the summerwood bands are narrow. Growthrings are generally most prominent on the flat-grained surfaces, which also frequently exhibit adimpled appearance. This appearance is common inlodgepole pine too, but in lodgepole the dimples aresmaller and more abundant. The resin canals ofponderosa pine are abundant and easily found inall annual rings. They are larger than those inlodgepole pine, and the heartwood of lodgepolepine is lighter colored than that of ponderosa.(Illustration, p. 22.)

29

Sitka spruce (Picea sitchensis)

Range.— Sitka spruce grows along the Pacificcoast from Alaska to northern California. Itis rarely found over 40 miles from the coast andgenerally grows in mixture with Douglas-fir,grand fir, western hemlock, and western redcedar.It occasionally forms pure stands.

Properties.— Sitka spruce is a moderately light-weight wood, averaging 28 pounds a cubic foot.The wood also is moderately soft, with a specificgravity of 0.37, moderately weak in bending andcompressive strength, moderately stiff, and moder-ately low in resistance to shock. On the basisof weight, however, it ranks high in strengthproperties.

Although the wood has moderately largeshrinkage, it is not difficult to kiln-dry. It workseasily, holds fastenings well, and can be obtainedin clear, straight-grained pieces of large size anduniform texture with hardly any hidden defects.Its decay resistance is low. Although planedsurfaces of Sitka spruce lumber may show a silkysheen, the wood has a tendency to produce woolyor fuzzy grain under the action of planer knives.As a pulpwood, Sitka spruce ranks high because of

its long, strong fibers and the ease with which itcan be pulped by any of the pulping processes.

Uses.—Sitka spruce is used principally forlumber, cooperage, and paper pulp. Some of thelumber is used for construction just as it comesfrom the sawmill, but the greater part is remanu-factured into various products. At least half ofthe remanufactured lumber goes into boxes andcrates. The other major uses of the lumber arefor furniture, planing-mill products, sash, doors,blinds, and general millwork. Specialty uses in-clude aircraft, ladder rails, and piano soundingboards.

Description.— Heartwood is light pinkish yellowto pale brown. Transition from springwood tosummerwood is gradual, making the annual ringsappear rather inconspicuous on flat-grained sur-faces. Resin canals are usually more prominentthan in the other spruces. On end-grain sur-faces, the canals appear as small dots or veryshort lines that run parallel to the growth ring.Flat-grained surfaces are lustrous and frequentlyexhibit dimpling. The pinkish color of the heart-wood distinguishes this species from all otherspruces. (Illustration, p. 23.)

Engelmann spruce (Picea engelmannii)

Range.—In the United States, Engelmannspruce grows along the upper slopes of the CascadeMountains in Washington, Oregon, and the ex-treme northern part of California, and in the RockyMountains in northeastern Washington, north-eastern Oregon, Idaho, Montana, Wyoming, Colo-rado, Utah, Arizona, and New Mexico. Thelargest producers of Engelmann spruce are Colo-rado, Montana, and Idaho.

Properties.— Engelmann spruce is rated as lightin weight, averaging 24 pounds a cubic foot. Thewood is soft, with a specific gravity of 0.32, and isweak as a beam or post, moderately limber, andlow in ability to resist shock.

Engelmann spruce can be readily air-dried withlittle tendency to warp. It has moderately smallshrinkage and stays in place well when properlydried. The wood is low in decay resistance butglues easily under a wide range of gluing condi-tions. Engelmann space has excellent pulpingand papermaking properties.

Uses.—Engelmann spruce is used principallyfor lumber and to a lesser extent for mine timbers,crossties, and poles. A large proportion of thelumber goes into building construction and boxes.Much of it is used for subflooring, sheathing, andstudding. Some Engelmann spruce is pulped forpaper.

Description.— Heartwood is not distinct fromsapwood and ranges from nearly white to paleyellowish brown. Transition from springwood tosummerwood is somewhat more abrupt than in theother spruces. Resin canals are present, but arefrequently difficult to find. They appear on verysmoothly cut, end-grain sections as small whitedots and on longitudinal surfaces as short, light-brown streaks or very fine grooves. The wood ofall the spruces, with the exception of Sitka, is verysimilar in its gross and microscopic features andtherefore almost impossible to tell apart. (Illus-tration, p. 23.)

30

Sugar pine (Pinus lambertiana)

Range.—Sugar pine grows from the Coast andCascade Mountain Ranges of southern Oregon,along the Coast Range and the Sierra Nevadaof California, through southern California inscattered stands, and into Mexico. The heavieststands and largest trees are found in Californiafrom Tulare to Eldorado Counties, in cool, moistsites on the west slope of the Sierra Nevada atelevations of 4,000 to 7,000 feet.

Properties.— Sugar pine is lightweight, averag-ing 25 pounds a cubic foot. The wood is moder-ately soft, with a specific gravity of 0.35, moder-ately limber, moderately weak, and low in shockresistance.

In decay resistance, sugar pine heartwood israted low to moderate. The wood has very smallshrinkage, seasons readily without checking orwarping, and stays in place well. It is easy towork with tools, does not split easily in nailing,and has moderate nail-withdrawal resistance.

Uses.—Sugar pine is used almost entirely forlumber in buildings, boxes and crates, sash, doors,frames, general millwork, and foundry patterns.It is suitable for all phases of house construction,with the high-grade material going into interiorand exterior trim, siding, and paneling, while thelower grade material is used for sheathing, sub-flooring, and roof boards.

The wood also has proved very satisfactory forcontainers because of its light weight and color,nailing properties, and freedom from taste andodor. Sugar pine is widely used for foundrypatterns because it meets the exacting require-ments and is readily available in wide, thickpieces practically free from defects.

Description.— Heartwood is light brown to palereddish brown. Resin canals are abundant andcommonly stain the surface of the wood withresin. Transition from springwood to summer-wood is gradual; making the growth rings appearless prominent on flat-grained surfaces. (Illustra-tion, p. 24.)

Western white pine (Pinus monticola)

Range.—Western white pine grows from theCanadian border southward into western Montanaand northern Idaho, and along the Cascade andSierra Nevada Mountains through Washingtonand Oregon to central California. The heavieststands occur in northern Idaho and in adjacentparts of Montana and Washington. The treesusually grow in mixture with western hemlock,western redcedar, western larch, grand fir, andDouglas-fir, but occasionally occur in pure standson limited areas.

Properties.-Moderately light in weight, west-ern white pine averages 27 pounds a cubic foot.The wood is moderately soft, with a specificgravity of 0.36, weak, moderately stiff, and mod-erately low in ability to resist shock.

Although the wood has moderately large shrink-age, it is easy to kiln-dry and stays in place wellafter seasoning. In decay resistance, it is rankedas low to moderate. Western white pine workseasily with tools and glues readily. It does not

split easily in nailing and occupies an intermediateposition in nail-withdrawal resistance.

Uses.-Practically all of the western white pinecut is sawed into lumber. About three-fourths ofthis lumber is used in building construction. Thelower grades are used for subflooring and wall androof sheathing, while the high-grade material ismade into siding of various kinds, exterior andinterior trim, partition, casing, base, and paneling.Other uses of western white pine include matchplanks, boxes, and millwork products.

Description.—Heartwood is cream colored tolight brown or reddish brown. Resin canals areabundant and transition from springwood tosummerwood is like that in sugar pine. Separationof western white pine and sugar pine is generallyaccomplished on the basis of the resin canals.which are larger in sugar pine than in the otherwhite pines. Microscopic characteristics, however,offer a more reliable means of differentiation thangross features. (Illustration, p. 24.)

31

Western larch (Larix occidentalis)

Range.—Western larch grows in mountainvalleys and on slopes at elevations of 2,000 to7,000 feet in Washington, Oregon, western Mon-tana, and northern Idaho. It reaches its bestdevelopment and greatest commercial importancein northern Idaho and western Montana, where itis generally associated with other species, althoughsometimes forming pure forests of limited extent.

Properties.— A heavy wood, western larch hasan average weight of 38 pounds per cubic foot.Also, it is moderately hard, with a specific gravityof 0.51, stiff, strong,shock resistance.

and moderately high in

Western larch and Douglas-fir are frequentlylogged together and sold in mixture under thecommercial name of “larch-fir.” Heartwood ofboth species is moderately decay resistant. West-ern larch has large shrinkage in drying and presentsseasoning problems because of the slowness withwhich it gives up its moisture. Although it ranks

high in nail-withdrawal resistance, small or blunt-pointed nails are preferred to reduce splitting.

Uses.—Western larch is used principally inbuilding construction as rough dimension, smalltimbers, planks, and boards. Considerableamounts also are made into crossties and minetimbers. Probably three-fourths of the lumberproduced is used for structural purposes as itcomes from the sawmill. Some of the high-gradelumber is remanufactured into interior finish,flooring, sash, doors, blinds, and other products.

Description.—Heartwood is russet brown andthe color is best seen in summerwood bands onflat-grained surfaces. Resin canals are present,but are very small and difficult to find unless theresin has stained the wood surfaces or the exuda-tion actually appears as very small droplets.Transition from springwood to summerwood isabrupt and there is little difference in color be-tween the two zones. The heartwood lacks adistinctive odor. (Illustration, p. 25.)

Douglas-fir (Pseudotsuga menziesii)

Range.-In the United States, Douglas-firgrows in most forests from the Rocky Mountainsto the Pacific coast and from the Mexican toCanadian borders. Botanically it is not a truefir. It reaches its largest size and fastest rate ofgrowth in Washington and Oregon, where largetrees form very dense forests that sometimesyield as much as 100,000 board-feet of lumberper acre.

Properties.— Most old-growth Douglas-fir fromthe Pacific coast and northern Rocky MountainStates is moderately heavy, very stiff, moderatelystrong, and moderately shock resistant. It aver-ages about 33 pounds a cubic foot. The wood isalso moderately hard, with an average specificgravity ranging from 0.40 to 0.48. Wide-ringedsecond-growth Douglas-fir from the coastal Statesand material grown in the southern Rocky Moun-tain States tends to be lighter in weight and tohave lower strength properties.

The wood of Douglas-fir can be readily kiln-dried if proper methods are used. Although it ismore difficult to work with handtools than the

soft pines, it holds fastenings well and can be gluedsatisfactorily. Dense heartwood has moderatedecay resistance.

Uses.—The principal uses of Douglas-fir arefor lumber, timbers, piling, and plywood. Re-manufactured lumber. goes mostly into sash, doors,general millwork, railroad car construction andrepair, and boxes and crates. Plywood is now inwide use for sheathing, concrete forms, prefabrica-ted house panels, millwork, ships and boats, andother structural forms. Chipped Douglas-fir saw-mill residue has a considerable market at pulp mills.

Description.—Heartwood is orange red to redor sometimes yellowish. Resin canals, which areseen as brownish streaks in the summerwood,appear to be more abundant and more readilydetectable than in western larch. Transition fromspringwood to summerwood is similar to that inwestern larch. The heartwood of Douglas-fir maybe confused with that of the southern yellow pines,but resin canals are larger and much more abun-dant in southern pines. Most Douglas-fir has adistinctive odor. (Illustration, p. 25.)

32

Range.—Western hemlock grows along the Pa-cific coast from Alaska to San Francisco Bay, andas far inland as northern Idaho and northwesternMontana. The best stands are found in the humidcoastal regions of Oregon, Washington, and Alaskaand on the lower slopes of the Cascade Mountainsin Washington and Oregon.

Properties.— Western hemlock is moderatelylight in weight, averaging 29 pounds a cubic foot,and moderately hard, with a specific gravity of0.38. It is also moderately weak and its shock re-sistance is fairly low. Although western hemlockhas moderately large shrinkage, it is comparativelyeasy to season. Heartwood is low in decay resist-ance but the wood is easy to work with tools andhas satisfactory gluing properties. Excellent forpapermaking, it yields a tough, strong, and easilybleached pulp.

Uses.—Western hemlock is used primarily forpulpwood and construction lumber and, to alimited extent, for containers, plywood core stock,crossties, and mine timbers. The pulp is used fornewsprint and other printing paper, tissues, wrap-

Western hemlock (Tsuga heterophylla)

ping papers, and viscose and other cellulose deriva-tives. Although little western hemlock goes intoheavy structural material, large quantities areused for sheathing, siding, subflooring, joists, stud-ding, planking, and rafters in light frame con-struction.

Description.—Heartwood of western hemlock islight reddish brown and frequently has a purplishcast, especially in the summerwood bands. Tran-sition from springwood to summerwood is gradualand on end-grain surfaces there is little color con-trast between the two zones. The wood lacksnormal resin canals.

Eastern hemlock heartwood is more roseate incolor than western hemlock and the transition fromspringwood to summerwood is so abrupt that thetwo zones stand out distinctly. The coarser tex-ture of eastern hemlock springwood tends to tearout in crosscut sawing and to produce a ribbed ap-pearance on the end grain. A smooth cut is diffi-cult to make on the end grain of eastern hemlock,even with a very sharp knife, while western hem-lock cuts very easily and produces smooth surfaces.(Illustration, p. 26.)

White Fir (Abies)

Species names.—White fir (Abies concolor),grand fir (A. grandis), Pacific silver fir (A. ama-bilis), California red fir (A. magnifica), and noblefir (A. procera).

Range.-Commercial white fir, which includesall the above species, grows throughout thePacific Coast and Rocky Mountain States. Thelargest, stands of white fir (A. concolor) probablyoccur in California, but other States containlarger stands of the other species.

Properties.— Commercial white fir is light inweight, the various species ranging from 26 to 28pounds a cubic foot. It is moderately soft, withan average specific gravity of 0.35, moderatelyweak, moderately low in shock resistance, mod-erately stiff, and low in nail-withdrawal resistance.It is difficult to season, a fact that retarded its useuntil satisfactory seasoning methods were devel-oped. Also, its decay resistance is low, but gluingproperties are satisfactory. White fir producesstrong, high-quality paper pulp.

Uses.-White fir is used principally for lumberand pulpwood. The lumber goes largely intobuilding construction, planing-mill products, boxesand crates, sash, doors, frames, and general mill-work. Probably 75 percent or more of all whitefir lumber is used for framing, subflooring, andsheathing of houses. Pulpwood is used chieflyin the manufacture of various grades of printingpaper and high-grade wrapping paper.

Description.— Heartwood is nearly white topale reddish brown and the wood lacks normalresin canals. Transition from springwood, likethat in eastern hemlock, is more abrupt thanin western hemlock. Also, color of springwoodand summerwood on end-grain surfaces is morecontrasting than in western hemlock. The bal-sam fir of the east is more uniformly white incolor, with less contrasting rings than the westernfirs. Wood rays of the western firs frequentlycontain colored material that makes them standout more on edge-grained surfaces than rays ofthe eastern firs, which are generally colorless.(Illustration, p. 26.)

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GLOSSARYAnnual growth ring.—The growth layer put on in a single

growth year, including springwood and summerwood.Bark.—Outer layer of a tree, comprising the inner bark,

or thin, inner living part (phloem) and the outerbark, or corky layer, composed of dry, dead tissue.

Beam.—A structural member supporting a load appliedtransversely to it.

Bending, steam.—The process of forming curved woodmembers by steaming or boiling the wood and bendingit to a form.

Bird’s-eye.— Small localized areas in wood with the fibersindented and otherwise contorted to form few tomany small circular or elliptical figures remotelyresembling birds’ eyes on the tangential surface.Common in sugar maple and used for decorativepurposes: rare in other hardwood species.

Bow.-The distortion in a board that deviates from flat-ness lengthwise but not across its faces.

Broad-leaved trees.—(See Hardwoods.)Cambium.—The one-cell-thick layer of tissue between the

bark and wood that repeatedly subdivides to formnew wood and bark cells.

Cell.—A general term for the minute units of woodstructure, including wood fibers, vessels members,and other elements of diverse structure and function.

Check.— A lengthwise separation of the wood, usuallyextending across the rings of annual growth andcommonly resulting from stresses set up in the woodduring seasoning.

Collapse.—The flattening of groups of cells in heartwoodduring the drying or pressure treatment of wood,characterized by a caved-in or corrugated appearance.

Crook.—The distortion in a board that deviates edgewisefrom a straight line from end to end of the board.

Cup.—The distortion in a board that deviates flatwisefrom a straight line across the width of the board.

Decay.— The decomposition of wood substance by fungi.Advanced (or typical) decay.-The older stage of decay

in which the destruction is readily recognized becausethe wood has become punky, soft and spongy, stringy,ringshaked, pitted, or crumbly. Decided discolora-tion or bleaching of the rotted wood is often apparent.

Incipient decay.—The early stage of decay that hasnot proceeded far enough to soften or otherwiseperceptibly impair the hardness of the wood. It isusually accompanied by a slight discoloration orbleaching of the wood.

Density.— The weight of a body per unit volume. Whenexpressed in the c. g. s. (centimeter-gram-second)system, it is numerically equal to the specific gravityof the same substance.

Diffuse-porous wood.—Certain hardwoods in which thepores tend to be uniform in size and distributionthroughout each annual ring or to decrease in sizeslightly and gradually toward the outer border of thering.

Dimension.—(See Lumber.)Dimension stock.—A term largely superseded by the term

hardwood dimension lumber. It is hardwood stockprocessed to a point where the maximum waste isleft at a dimension mill, and the maximum utility isdelivered to the user. It is stock of specified thickness,width, and length, in multiples thereof. According tospecification, it may be solid or glued; rough or sur-faced; semifabricated or completely fabricated.

Dimensional stabilization.—Reduction through specialtreatment in swelling and shrinking of wood, causedby changes in its moisture content with changes inrelative humidity.

Dry kiln.-(See Kiln.)Dry rot.-A term loosely applied to any dry, crumbly rot

but especially to that which, when in an advancedstage, permits the wood to be crushed easily to a drypowder. The term is actually a misnomer, since allwood-rotting fungi require considerable moisturefor growth.

Early wood.—(See Springwood.)Edge-grained.—(See Grain.)Extractives.— Substances in wood, not an integral part of

the cellular structure, that can be removed by solutionin hot or cold water, ether, benzene, or other solventsthat do not react chemically with wood components.

Fiber, wood.—A comparatively long (one twenty-fifth orless to one-third inch), narrow, tapering wood cellclosed at both ends.

Figure.— The pattern produced in a wood surface by annualgrowth rings, rays, knots, deviations from regulargrain such as interlocked and wavy grain, and irregularcoloration.

Finish.—Wood products to be used in the joiner work,such as doors and stairs, and other fine work requiredto complete a building, especially the interior.

Flakes.—(See Rays, wood.)Flat-grained.—(See Grain.)Framing.— Lumber used for the structural members of a

building, such as studs and joists.Girder.— A large or principal beam used to support con-

centrated loads at points along its length.Grade.-The designation of quality of a manufactured

piece of wood or of logs.Grain.—The direction, size, arrangement, appearance, or

quality of the elements in wood or lumber. To have aspecific meaning the term must be qualified.

Close-grained wood.—Wood with narrow, inconspicuousannual rings. The term is sometimes used to desig-nate wood having small and closely spaced pores, butin this sense the term “fine textured” is more oftenused.

Coarse-grained wood.—Wood with wide conspicuousannual rings in which there is considerable differencebetween springwood and summerwood. The term issometimes used to designate wood with large pores,such as oak, ash, chestnut, and walnut, but in thissense the term “coarse textured” is more often used.

Cross-grained wood.—Wood in which the fibers deviatefrom a line parallel to the sides of the piece. Crossgrain may be either diagonal or spiral grain, or acombination of the two.

Curly-grained wood.—Wood in which the fibers aredistorted so that they have a curled appearance, asin “bird’s-eye” wood. The areas showing curly grainmay vary up to several inches in diameter.

Diagonal-grained wood.—Wood in which the annualrings are at an angle with the axis of a piece as aresult of sawing at an angle with the bark of the treeor log. A form of cross grain.

Edge-grained lumber.—Lumber that has been sawed sothat the wide surfaces extend approximately at rightangles to the annual growth rings. Lumber is con-sidered edge grained when the rings form an angle of45° to 90° with the wide surface of the piece.

Fine-grained wood.—(See Grain, close-grained wood.)Flat-grained lumber.—Lumber that has been sawed so

the wide surfaces extend approximately parallel to theannual growth rings. Lumber is considered flatgrained when the annual growth rings make an angleof less than 45° with the surface of the piece.

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Grain—ContinuedInterlocked-arained wood.—Wood in which the fibers are

inclined in one direction in a number of rings of annualgrowth, then gradually reverse and are inclined in anopposite direction in succeeding growth rings, thenreverse again.

Open-grained wood.—Common classification by paintersfor woods with large pores, such as oak, ash, chestnut,and walnut. Also known as “coarse textured.”

Plainsawed lumber.—Another term for flat-grainedlumber.

Quartersawed lumber.—Another term for edge-grainedlumber.

Spiral-grained wood.—Wood in which the fibers take aspiral course about the trunk of a tree instead of thenormal vertical course. The spiral may extend in aright-handed or left-handed direction around the treetrunk. Spiral grain is a form of cross grain.

Straight-grained wood.—Wood in which the fibers runparallel to the axis of a piece.

Vertical-grained lumber.—Another term for edge-grainedlumber.

Wavy-grained wood.—Wood in which the fibers collec-tively take the form of waves or undulations.

Green.—Freshly sawed lumber, or lumber that has receivedno intentional drying; unseasoned. The term doesnot apply to lumber that may have become completelywet through waterlogging.

Hardwoods.— Generally, the botanical group of trees thathave broad leaves, in contrast to the conifers or soft-woods. The term has no reference to the actualhardness of the wood.

Heartwood.— The wood extending from the pith to thesapwood, the cells of which no longer participate inthe life processes of the tree. Heartwood may beinfiltrated with gums, resins, and other materials thatusually make it darker and more decay resistant thansapwood.

Honeycombing.—Checks, often not visible at the surface,that occur in the interior of a piece of wood, usuallyalong the wood rays.

Joint.—The junction of two pieces of wood or veneer.Joist.—One of a series of parallel beams used to support

floor and ceiling loads and supported in turn by largerbeams, girders,-or bearing walls.

Kiln.— A heated chamber for drying lumber, veneer, andother wood products.

Knot.—That portion of a branch or limb which has beensurrounded by subsequent growth of the wood of thetrunk or other portion of the tree. As a knot appearson the sawed surface, it is merely a section of theentire knot, its shape depending upon the directionof the cut.

Longitudinal.— Generally, the direction along the lengthof the grain of wood.

Lumber.—The product of the saw and planing mill, notfurther manufactured than by sawing, resawing, pass-ing lengthwise through a standard planing machine,cross-cutting to length, and matching.

Boards.— Yard lumber less than 2 inches thick and 1or more inches wide.

Dimension.—Lumber from 2 inches to, but not including5 inches thick, and 2 or more inches wide.

Dressed size.—The dimensions of lumber after shrinkingfrom the green dimensions and being surfaced witha planing machine to usually 3/8 or ½ inch less thanthe nominal or rough size. For example, a 2- by4-inch stud actually measures 1 5/8 by 3 5/8 inches underAmerican lumber standards for softwood lumber.

Nominal size.—As applied to timber or lumber, therough-sawed commercial size by which it is knownand-sold in the market.

Structural lumber.—Lumber that is 2 or more inchesthick and 4 or more inches wide. intended for usewhere working stresses are required. The grading ofstructural lumber is based on the strength of thepiece and the use of the entire piece.

Timbers.—Lumber 5 or more inches in least dimension.Timbers may be classified as beams, stringers, posts,caps, sills, girders, purlins, etc.

Medullary rays.—(See Rays, wood.)Millwork.— Generally, all building materials made of

finished wood and manufactured in millwork plantsand planing mills. Includes such items as insideand outside doors, window and door frames, blinds,porch work, mantels, panel work, stairways, moldings,and interior trim. Does not include flooring, ceiling,or siding.

Moisture content of wood.—The amount of water containedin the wood. Usually expressed as a percentage ofthe weight of the ovendry wood.

Naval stores.—A term applied to the oils, resins, tars, andpitches derived from oleoresin contained in, exuded by,or extracted from trees chiefly of the pine species(genus Pinus) or from the wood of such trees.

Old growth.—Timber growing in or harvested from amature, naturally established forest. When the treeshave grown most or all of their individual lives inactive competition with their companions for sun-light and moisture, this timber is usually straightand relatively free of knots.

Ovendry wood. Wood dried to constant weight in anoven at temperatures above that of boiling water(usually 101° to 105° C. or 214° to 221° F.).

Peck.—Pockets or areas of disintegrated wood caused byadvanced stages of localized decay in the living tree.It is usually associated with cypress and incense-cedar. There is no further development of peckonce the lumber is seasoned.

Pitch pocket.—An opening that extends parallel to theannual growth rings and that contains, or has con-tained, either solid or liquid pitch.

Pitch streak.—A well-defined accumulation of pitch in amore or less regular streak in the wood of certainsoftwoods.

Pith.—The small, soft core occurring in the structuralcenter of a tree trunk, branch, twig, or log.

Plainsawed.— (See Grain.)Planing-mill products.—Products worked to pattern, such

as flooring, ceiling, and siding.Plywood.— An assembly made of layers (plies) of veneer, or

of veneer in combination with a lumber core, joinedwith an adhesive. The grain of adjoining plies isusually laid at right angles, and almost always an oddnumber of plies are used to obtain balanced con-struction.

Pore.—(See Vessels.)Porous woods.—Another name for hardwoods, which fre-

quently have vessels or pores large enough to be seenreadily without magnification.

Preservative.—Any substance that is effective, for a reason-able length of time, in preventing the developmentand action of wood-rotting fungi, borers of variouskinds, and harmful insects that deteriorate wood.

Quartersawed.—(See Grain.)Radial.—Coincident with a radius from the axis of the tree

or log to the circumference. A radial section is alengthwise section in a plane that extends from pithto bark.

Rate of growth.—The rate at which a tree has laid on wood.measured radially in the trunk or in lumber cut fromthe trunk. The unit of measure in use is number ofannual growth rings per inch.

Rays, wood—Strips of cells extending radially within a treeand varying in height from a few cells in some speciesto 4 or more inches in oak. The rays serve primarilyto store food and transport it horizontally in the tree.

Resin passage (or duct) .—Intercellular passages that con-tain and transmit resinous materials. On a cut sur-face, they are usually inconspicuous. They may ex-tend vertically parallel to the axis of the tree or atright angles to the axis and parallel to the rays.

Ring-porous woods.—A group of hardwoods in which thepores are comparatively large at the beginning of eachannual ring and decrease in size more or less abruptlytoward the outer portion of the ring, thus forming adistinct inner zone of pores, known as the springwood,and an outer zone with smaller pores, known as thesummerwood.

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Sap.—All the fluids in a tree except special secretions andexcretions, such as oleoresin.

Sapwood.— The living wood of pale color near the outsideof the log. Under most conditions the sapwood ismore susceptible to decay than heartwood.

Seasoning.— Removing moisture from green wood in orderto improve its serviceability.

Air-dried.— Dried by exposure to air, usually in a yard,without artificial heat.

Kiln-dried.— Dried in a kiln with the use of artificial heat.Second growth.—Timber that has grown after removal by

cutting, fire, wind, or other agency, of all or a largepart of the previous stand.

Sheathing.— The structural covering, usually of boards orfiberboards, placed over exterior studding or rafters ofa structure.

Softwoods.—Generally, the botanical group of trees thatbear cones and in most cases have needlelike or scale-like leaves; also the wood produced by such trees. Theterm has no reference to the actual hardness of thewood.

Specific gravity.—The radio of the weight of a body tothe weight of an equal volume of water at 4° C. orother specified temperature.

Springwood.— The portion of the annual growth ring thatis formed during the early part of the season’s growth.In most softwoods and in ring-porous hardwoods, iti s l e s s d e n s e a n d w e a k e r m e c h a n i c a l l y t h a nsummerwood.

Stain.— A discoloration in wood that may be caused bysuch diverse agencies as micro-organisms, metal, orchemicals. The term also applies to materials usedto color wood.

Strength.— The term in its broader sense includes all theproperties of wood that enable it to resist differentforces or loads. In its more restricted sense, strengthmay apply to any one of the mechanical properties,in which event the name of the property under con-sideration should be stated. thus: strength in com-pression parallel to grain, strength in bending, hard-ness, and so on.

Stess.—Force per unit of area.Stud.— One of a series of slender wood structural members

used as supporting elements in walls and partitions.Summerwood.—The portion of the annual growth ring

that is formed after the springwood formation hasceased. In most softwoods and in ring-porous hard-woods, it is denser and stronger mechanically thanspringwood.

Tangential.— Strictly, coincident with a tangent at thecircumference of a tree or log, or parallel to such at a n g e n t . I n p r a c t i c e , h o w e v e r , i t o f t e n m e a n sroughly coincident with a growth ring. A tangentialsection is a longitudinal section through a tree orlimb and is perpendicular to a radius. Flat-grainedand plainsawed lumber is sawed tengentially.

Texture.— A term often used interchangeably with grain.Sometimes used to combine the concepts of densityand degree of contrast between springwood andsummerwood. In this publication, texture refers tothe finer structure of the wood (see Grain) rather thanthe annual rings.

Twist.—A distortion caused by the turning or windingof the edges of a board so that the four corners ofany face are no longer in the same plane.

Tyloses.— Masses of cells appearing somewhat like frothin the pores of some hardwoods, notably white oakand black locust. In hardwoods, tyloses are formedwhen walls of living cells surrounding vessels extendinto the vessels. They are sometimes formed insoftwoods in a similar manner by the extension ofcell walls into resin-passage cavities.

Veneer.—A thin layer or sheet of wood cut on a veneermachine.

Rotary-cut veneer.—Veneer cut in a lathe which rotatesa log or bolt, chucked in the center, against a knife.

Sawed veneer.—Veneer produced by sawing.Sliced veneer.—Veneer that is sliced off a log, bolt, or

flitch with a knife.Vertical grain.—(See Grain.)Vessels.—Wood cells of comparatively large diameter

that have open ends and are set one above the otherso as to form continuous tubes. The openings of thevessels on the surface of a piece of wood are usuallyreferred to as pores.

Virgin growth.—The original growth of mature trees.Wane.—Bark or lack of wood from any cause on the

edge or corner of a piece of lumber.Warp.— Any variation from a true or plane surface.

Warp includes bow, crook, cup, and twist, or anycombination thereof.

Weathering.— The mechanical or chemical disintegrationand discoloration of the surface of wood that iscaused by exposure to light, the action of dust andsand carried by winds, and the alternate shrinkingand swelling of the surface fibers with the continualvariation in moisture content brought by changes inthe weather. Weathering does not include decay.

Wood substance.—The solid material of which wood iscomposed. It usually refers to the extractive-freesolid substance of which the cell walls are composed,but this is not always true. There is no wide varia-tion in chemical composition or specific gravitybetween the mood substance of various species; thecharacteristic differences of species are largely due todifferences in infiltrated materials and variations inrelative amounts of cell walls and cell cavities.

Workability.— The degree of ease and smoothness of cutobtainable with hand or machine tools.

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