Biermann Ch. Handbook of Pulping and Papermaking

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564 26. SOFTWOOD ANATOMY

considerable amount of the remanufactured lum-

ber. Other important uses are furniture, planing

mill products, sash, doors, blinds, mill work, and

boats.

Sitka spruce has been by far the most

important wood for aircraft construction. Other

specialty uses are ladder rails and sounding boards

for pianos.

Color. The heartwood of Sitka spruce is a

light brown with a pinkish or purple cast and is

darker than that of eastern spruce. The sapwood

is creamy white and shades gradually into the

heartwood; it may be 3 to 6 in. wide or even

wider in young trees. The wood has a compara-

tively fine, uniform texture, generally straight

grain, and no distinct taste or odor.

Macrostructure. The dimpled grain, if

present, its darker and pinkish heartwood, and its

somewhat larger resin canals help identify it. It

may be mistaken for soft pine.

Microstructure. This species is separated

from other spruce by the occurrence of biseriate

pitting in longitudinal tracheids. Its ray cells may

contain darker (brownish) deposits than other

species and crystals.

Fig. 26-28. Picea sitchensis.

Fig. 26-29. Sitka spruce (Picea sitchensis) (50x).

ANATOMY OF SOFTWOOD SPECIES 565

Engelmann spruce (Fig. 26-30)

Engelmann spruce

{Picea engelmannii)

grows

at high elevations in the Rocky Mountain region of

the United States. It is known by other names,

such as white spruce, mountain spruce, Arizona

spruce, silver spruce, and balsam. About 60% of

the lumber comes from the southern Rocky Moun-

tain States, with most of the remainder from the

northern Rocky Mountain States and Oregon.

Uses. The wood has medium to fine texture.

It is generally straight grained. Engehnann spruce

is rated as light in weight. It is low in strength as

a beam or post. It is limber, soft, low in shock

resistance, and has moderately small shrinkage.

The lumber typically contains numerous small

knots.

Engelmann spruce is used for lumber,

mine timbers, railroad ties, and poles. It is used

also in building construction in the form of dimen-

sion stock, flooring, sheathing, and studding. It

has excellent properties for pulp and papermaking.

Color. The heartwood of Engelmann spruce

is nearly white with a slight tinge of red. The

sapwood is 3/4 to 2 in. wide and is often difficult

to distinguish from heartwood, except for its high

moisture content in green timbers.

Macroscopic features. The transition from

earlywood to latewood is somewhat more abrupt

than in other spruces. Resin canals are present,

comparatively few, and are often difficult to find.

They often appear as white dots in the latewood.

The rays are very fine; the ftisiform rays occur

sporadically and are widely spaced.

Similar woods. Engelmann spruce is easily

confused with the white (true) firs and lodgepole

pine,

which have almost white heartwoods. The

true firs lack resin canals. Engelmann spruce

lacks the dimpled surface of lodgepole pine.

Norway spruce

Norway spruce {P. abies) is native to Eu-

rope.

It has been planted in the northeast U.S.

ABIES

Uses. The white firs are very useful in pulp

products and produces strong, high-quality paper.

Color. The wood of the true firs {Abies) is

creamy white to pale brown. The heartwood and

sapwood are usually indistinguishable. The simi-

larity of wood structure in the true firs makes it

Fig. 26-30.

Picea engelmannii

(Koehler, 1917)

impossible to distinguish the species by an exami-

nation of the wood alone. Firs tend to be intoler-

ant (of shade, when growing) and are, therefore,

often fast growing with wide growth rings having

especially gradual transition to latewood.

Fig,

26-31.

Abies spp.

566 26. SOFTWOOD ANATOMY

Microscopic structure. Resin canals and ray

tracheids are absent, end walls of ray parenchyma

are nodular, and cross—field pits are nodular. A.

lasiocarpa may be foul smelling with knots that

are a distinct yellow color. Crystals may be found

in all species, but especially in A. magnifica and

concolor. In the eastern species and A,

lasiocarpa

the ray parenchyma contents are yellow

to clear, while those of the other species are

reddishbrown. Generally the true firs have taller

rays than the hemlocks.

Hoadley (1990) describes the use of Ehrich's

reagent (4 parts /^—dimethyl amino benzaldehyde

dissolved in 92 parts ethanol made acidic by

adding 8 parts concentrated HCl) to distinguish

subalpine fir (which turns purple) from Pacific

silver fir (which remains clear or pale green).

Eastern species (Figs. 26-31 and 26-32)

Balsam fir

{Abies balsamea)

grows principal-

ly in New England, New York, Pennsylvania, and

the Lake States; it is the only eastern Abies of

commercial importance. Eraser fir (.4. fraseri) has

limited distribution in the Appalachian Mountains

of Virginia, North Carolina, and Tennessee; this

species sometimes has resinous tracheids (near

parenchyma) in the heartwood that are filled with

reddish brown to black amorphous deposits.

Balsam fir is light in weight when dry, low in

bending and compressive strength, moderately

limber, soft, and low in resistance to shock. The

eastern firs are used mainly for pulpwood, al-

though some lumber is produced from them,

especially in New England and the Lake States.

Balsam fir latewood often has a light purple cast to

it. See eastern spruce for additional information.

Western

species (Fig. 26-33)

Six commercial species make up the western

true firs: subalpine fir

{Abies

lasiocarpa), Califor-

nia red fir (.4. magnifica), grand fir {A. grandis),

noble fir {A. procera). Pacific silver fir {A.

amabilis),

and white fir {A. concolor).

The western firs are light in weight, but, with

the exception of subalpine fir, have somewhat

higher strength properties than balsam fir. Wood

Fig. 26-32. Balsam fir (Abies

balsamea)

(50x).

ANATOMY OF SOFTWOOD SPECIES 567

shrinkage is small to moderately large. The

sapwood is not distinguishable from the heartwood

in some of these species.

The western true firs are largely cut for

lumber in Washington, Oregon, California, west-

em Montana, and northern Idaho and marketed as

white fir throughout the U.S. Lumber of the

western true firs goes into building construction,

boxes and crates, and general millwork. In house

construction, the lumber is used for framing,

subflooring, and sheathing. Some western true fir

lumber goes into boxes and crates. High—grade

lumber from noble fir is used mainly for interior

finish, moldings, siding, and sash and door stock.

The best material is used for aircraft construction

and ladder rails.

Macroscopic structure. Resin canals are

normally absents, but occasionally traumatic resin

canals are present in the outer latewood in tangen-

tial rows extending 1/8 in. or more. A. grandis

sometimes has resinous tracheids (near parenchy-

ma) in the heartwood that are filled with reddish

brown to black amorphous deposits.

Similar woods. Western hemlock is very

similar, but microscopic features can be used to

distinguish these two woods. Western fir has

taxodioid cross—field pits and lacks ray tracheids.

LARIX

Larix species have resin canals with

thick—walled epithelium cells. There is an abrupt

transition from earlywood to latewood. The

bordered pitting of vertical tracheids is often

biseriate. Eastern larch has lighter color heart-

wood (more yellow than brown), a lower degree

of biseriate bordered pitting, and a finer texture

than western larch.

Western

larch (Figs. 26-34 and 26-35)

Western larch {Larix occidentalis) grows in

western Montana, northern Idaho, northeastern

Oregon, and the eastern slope of the Cascade

Mountains in Washington. About 2/3 of the

lumber of this species is produced in Idaho and

Montana and 1/3 in Oregon and Washington.

Uses. The wood is

stiff,

moderately strong

Fig 26-33. White fir (A6fe5co/ico/(ir)(50x).

568 26. SOFTWOOD ANATOMY

and hard, moderately high in shock resistance, and

moderately heavy. It has moderately large shrink-

age.

The wood is usually straight grained, splits

easily, and is subject to ring shake. Kiiots are

common but small and tight. Western larch is

used mainly in building construction for rough

dimension, small timbers, planks and boards, and

for railroad tie and mine timbers. It is used also

for piles, poles, and posts. Some high—grade

material is manufactured into interior finish,

flooring, sash, and doors.

Color. The heartwood of western larch is

yellowish brown and the sapwood is yellowish

white. The sapwood is generally 0.5—0.75 in.

and not more than 1 in. thick.

Macrostructure. The wood has a very abrupt

transition to the narrow, conspicuous latewood.

The resin canals occur sporadically and may be in

tangential groups. Microstructure. Marginal

parenchyma are occasionally present.

Eastern

larch,

tamarack (Fig. 26-36)

Tamarack {Larix laricina) is a small—to

medium—sized tree with a straight, round slightly

Fig. 26-34. Larix occidentalis.

Fig. 26-35. Western larch {Larix

occidentalis)

(50x).

tapered trunk. In the U.S. it grows from Maine to

Minnesota, with the bulk of the stands in the Lake

States. It was formerly used in considerable

quantity for lumber, but in recent years production

for that purpose has been small.

The heartwood of tamarack is yellowish

brown to russet brown. The sapwood is whitish,

generally less than an inch wide. The wood is

coarse in texture, without odor or taste, and the

transition from earlywood to latewood is abrupt.

The wood is intermediate in weight and in most

mechanical properties.

Tamarack is used principally for pulpwood,

lumber, railroad ties, mine timbers, fuel, fence-

posts,

and poles. Lumber goes into framing

material, tank construction, boxes, and pallets.

European larch

European larch {Larix decidua), native to

Europe, is planted in Canada and northeast U.S.

TSUGA

The presence of ray tracheids is useful in

distinguishing the hemlocks, especially western

hemlock, from the true firs {Abies). The growth

ANATOMY OF SOFTWOOD SPECffiS 569

rate of hemlock (especially eastern hemlock) can

vary greatly even in a relatively small sample. A

smooth cut is difficult to make on the end grain of

eastern hemlock (using a knife), but is easily made

on western hemlock. Western hemlock wood may

have traumatic resin canals, is less splintery, and

is usually free of cup shake.

Eastern

hemlock

Eastern hemlock (Tsuga canadensis) grows

from New England to northern Alabama and

Georgia, and in the Lake States. Other names are

Canadian hemlock and hemlock spruce. The

production of hemlock lumber is divided fairly

evenly between the New England States, the

Middle Atlantic States, and the Lake States.

Uses. The wood is moderately light in

weight, moderately hard, moderately low in

strength, moderately limber, and moderately low

in shock resistance. It is used principally for

lumber and pulpwood. The lumber is used largely

in building construction for framing, sheathing,

subflooring, and roof

boards,

and in the manufac-

ture of boxes, pallets, and crates.

Fig. 26-36. Tamarack, eastern larch

{Larix laricina) (50

x).

570 26. SOFTWOOD ANATOMY

Color. The heartwood of eastern hemlock is

pale brown with a reddish hue. The sapwood is

not distinctly separated from the heartwood but

may be lighter in color. The wood is coarse and

uneven in texture (old trees tend to have consider-

able shake).

Similar woods. Spruce is lighter in color,

weighs less, does not tend to splinter, and has

resin canals. Most of the firs are of light color,

especially in the earlywood, and do not tend to

splinter. Noble fir should be distinguished with a

microscope.

Western hemlock (Figs. 26-37 and 26-38)

Western hemlock (Tsuga

heterophylla)

(alias

west coast hemlock, hemlock spruce, western

hemlock spruce, western hemlock fir. Prince

Albert fir, gray fir, silver fir, and Alaska pine)

grows along the Pacific coast of Oregon and

Washington and in the northern Rocky Mountains,

north to Canada and Alaska. Mountain hemlock,

T. mertensiana, inhabits mountainous country from

central California to Alaska; it is treated as a

separate species in assigning lumber properties.

Fig. 26-37.

Tsuga

heterophylla.

Fig. 26-38. Western hemlocl^

{Tsuga heterophylla)

(50x).

ANATOMY

SOFTWOOD SPECIES

571

Uses. Western hemlock

moderately light

in weight and moderate

strength.

It is

moderate

its

hardness, stiffness,

and

shock resistance.

has moderately large shrinkage, about

the

same

Douglas—fir. Green hemlock lumber contains

considerably more water than Douglas—fir

and

requires longer kiln drying time. Western hem-

lock

used mainly

for

pulpwood, lumber,

and

plywood.

The

lumber goes largely into building

material, such

sheathing, siding, subflooring,

joists,

studding, planking,

and

rafters. Major

quantities

are

used

in the

manufacture

pallets,

crates,

and

flooring,

and

smaller amounts

for

ftirniture and ladders.

Color.

The

heartwood

and

sapwood

western hemlock

are

almost white with

purplish

tinge.

The

sapwood, which

sometimes lighter

in color,

generally

not

more than

inch thick.

The wood contains small, sound, black knots that

are usually tight

and

stay

place. Dark streaks

often found

in the

lumber

and

caused

hemlock

bark maggots

as a

rule

do not

reduce strength.

CUPRESSACEAE

CHAMAECYPARISiVdXst

cypresses)

Alaska—cedar (¥\g. 26-39)

Alaska—cedar

(Chamaecyparis

nootkatensis)

grows

in the

Pacific coast region from southeast-

ern Alaska

southern Oregon.

Uses. The wood

fine textured and general-

ly straight grained.

It is

moderately heavy, mod-

erately strong

and stiff,

moderately hard,

and

moderately high

resistance

shock. Alas-

ka—cedar shrinks little

drying,

stable

in use

after seasoning,

and the

heartwood

very resis-

tant

decay.

The

wood

has a

mild, unpleasant,

characteristic odor that resembles that

of raw

potatoes. Alaska—cedar is used

for

interior finish,

furniture, small boats, cabinetwork,

and

novelties.

Color.

The

heartwood

Alaska—cedar

bright, clear yellow;

tends

darken somewhat

with exposure

to air. The

sapwood

narrow,

white

yellowish,

and

hardly distinguishable

from

the

heartwood.

The

growth rings tend

to be

very narrow

and

inconspicuous.

Microscopic structure.

The ray

tracheids

may

large. Some rays have

parenchyma.

Ray

and

longitudinal parenchyma

end

walls

are

nodular with indentures.

Fig. 26-39. Chamaecyparis nootkatensis.

Port—Orford—cedar (Figs. 26-40

and

26-41)

Port—Orford—cedar (Chamaecyparis

lawsoniana)

(alias Lawson cypress, Oregon cedar,

and white cedar) grows along

the

Pacific coast

from Coos

Bay,

Oregon, southward

California.

It does

not

extend more than

miles inland.

Uses.

It is

moderately light

weight,

stiff,

moderately strong

and

hard,

and

moderately

resistant

shock. Port—Orford—cedar heart-

wood

highly resistant

decay.

The

wood

shrinks moderately,

has

little tendency

warp,

and

stable after seasoning. Some high—grade

Port—Orford—cedar

was

used

in the

manufacture

of battery separators. Other uses

are

venetian-

blind slats, mothproof boxes, archery supplies,

sash

and

door construction, stadium seats, floor-

ing, interior finish, furniture,

and

boatbuilding.

Color.

The

heartwood

Port—Orford—

cedar

light yellow

pale brown

color

and

has

strong, pungent odor.

The

sapwood

narrow (1—3

in.)

and hard

distinguish from

the

heartwood.

The

wood

has a

fine, even texture,

generally straight grain,

and a

pleasant spicy

(ginger—like) odor

and a

bitter, spicy taste.

572 26. SOFTWOOD ANATOMY

Macroscopic structure. Longitudinal paren-

chyma are usually visible (wetting helps) with a

lens as reddish lines or zones.

Microscopic structure. Ray tracheids are

lacking, ray parenchyma have smooth end walls,

and the transverse walls of the vertical parenchy-

ma are nodular.

Atlantic white—cedar

This species is strictly a swamp tree and is

very similar in properties and uses to northern red

cedar; both grow in the eastern U.S.

Chamaecyparis thyoids is also known as juniper,

southern white—cedar, swamp cedar, and boat

cedar; it grows near the Atlantic coast from

Maine to northern Florida and westward along the

gulf coast to Louisiana. Commercial production

centers in North Carolina and along the gulf coast.

White—cedar lumber is used principally where a

high degree of durability is needed, as in tanks

and boats, and for woodenware.

Color. The heartwood is light brown with a

reddish cast that is sharply demarcated from the

sapwood. It is aromatic and has a similar odor to

that of northern white—cedar.

Fig. 26-40. Chamaecyparis lawsoniana.

Fig.

26-41.

Port-Orford cedar

{Chamaecyparis lawsoniana)

(50x).

ANATOMY OF SOFTWOOD SPECIES 573

Microscopic structure. Ray tracheids are

lacking, ray parenchyma have smooth end walls,

and the transverse walls of the vertical parenchy-

ma are smooth.

JUNIPERUS

The heartwood of trees of this genus are all

aromatic with a pencil or cedar chest smell.

Eastern and southern species have deep red heart-

wood; the western species are more brownish in

color. Western juniper is J. occidentalis (Figs.

26-42 and 26-43).

Microscopic features. This genus is charac-

terized by large amounts of vertical parenchyma

with dark colored contents, nodular end

walls,

and

indenture. Intercellular spaces occur between

vertical tracheids.

Eastern redcedar (Fig. 26-44)

Eastern redcedar (Juniperus virginiana)

grows throughout the eastern half of the United

States, except in Maine, Florida, and a narrow

strip along the gulf coast, and at the higher eleva-

tions in the Appalachian Mountain Range. Com-

Fig. 26-42. Juniperus occidentalis.

Fig. 26-43. Western juniper

{Juniperus occidentalis)

(50

X).