divide, are, Sweet Birch (_Betula lenta_), Yellow Birch (_Betula
lutea_), River Birch (_Betula nigra_), Paper Birch (_Betula
papyrifera_), White Birch (_Betula populifolia_) and Blue Birch
(_Betula cærulea_). The western birches, none of which are known to
extend much east of the continental divide, are: Western Birch
(_Betula occidentalis_), Mountain Birch (_Betula fontinalis_), White
Alaska Birch (_Betula alaskana_), and Kenai Birch (_Betula
kenaica_). The last two occur in Alaska, but not in United States
proper.
It attains a height of seventy or eighty feet, and a diameter of two or
three. It prefers deep, moist, rich soil, but will grow in comparatively
dry, rocky ground. Its seeds are produced in large numbers and are
scattered by the wind a hundred feet or more from the parent tree. They
lack the wing power and the buoyancy of the seeds of some of the other
birches, but they manage to get themselves sown in sufficient numbers,
and their powers of germination are good.
The young seedling comes into existence with smooth bark, but it does
not keep it through life. As age increases, the bark becomes rough and
black. It is not shed in papery rolls and flakes as is the bark of river
birch, yellow birch, and paper birch, with which it is associated in
some parts of its range. It is generally an easy tree to identify and
the black, rough bark is generally a sufficient guide.
The sweet birch is tapped like sugar maple, but not for the same purpose
or to the same extent--only an occasional tree. Immense quantities of
sap will flow from it during the two or three weeks when the buds are
swelling in the spring. It is said that as much as two tons has been
known to flow from a medium sized birch in a single season. The sap is
made into a beer which has some commercial value, but is chiefly used
locally. One of the ways of making it, employed by farmers and woodsmen,
is to jug the sap, put in a handful of shelled corn, and let
fermentation do the rest.
A substance known in commerce as oil of wintergreen is procured almost
exclusively from this birch, though occasionally it is made from the
small wintergreen plant (_Gaultheria procumbens_). The product is
manufactured in very crude stills made by mountaineers in Pennsylvania
and southward along the mountains where sweet birch is abundant.
Frequently the woodsman’s whole family go into the business, chopping
down birch bushes and hacking them with hatchets into chips of the
desired sizes. The oil is extracted from the hogged mass by a steaming
and roasting process. It is sold by the quart to country storekeepers
who ship it to wholesale druggists where it is refined and used to
flavor candy, medicine, and drugs. The woodsman who manufactures the oil
prefers young birches from half an inch to two or three inches in
diameter, and he usually procures them in old logging grounds where
seedlings have sprung up. It is said that on an average one hundred
small birch trees are destroyed for each quart of oil that goes to
market. It is a process wasteful in the extreme.
In the open ground, sweet birch develops a full crown, short trunk,
abundance of limbs, with numerous slender, graceful twigs and small
branches. Its leaves form a dense mass, and they are so free from
attacks by insects and worms that diseased foliage is unusual. That
cannot be said, however, of the trunk. It is not particularly liable to
disease, but many old trees show the results of decay. It is of slow
growth, and a small tree may be much older than its size indicates. The
sapwood is generally thick, heartwood forms slowly, and the contrast in
color between sap and heart is strong.
The wood of sweet birch had few uses in early times, except fuel. The
pioneer sawmill had little to do with it. Lumber was hard to saw and was
seasoned with difficulty. Its tendency to warp was too great a tax on
the lumberman’s patience and ingenuity. The only way he could hold it
straight was to cob a few layers in the bottom of a pile, and stack
thousands of feet of other lumber on top, and leave it a year or two.
That was generally too much trouble, particularly when the wood had slow
sale, and the price was low. Birch reached market in large quantities
only when modern mills and improved drykilns came into existence.
The wood is heavy, strong, hard, in color dark brown tinged with red.
The light brown or yellow sapwood generally makes up seventy or eighty
annual rings. The difference between springwood and that of the later
season is not clearly marked, and consequently the rings are often
indistinct. The wood is very porous, and the pores are diffused through
all parts of the ring. They are too small to be seen with the naked eye,
except under the most favorable conditions. The medullary rays are
numerous but so small that they appear on the quartered wood merely as a
gloss, which, however, gives the surface a rich appearance.
Forms known as curly and wavy birch are highly esteemed. They are
accidents of growth, well developed in birch, and occurring in several
other woods. Difficulties are encountered in assigning sweet birch its
individual place in the industrial world. As a tree it is well known,
but that is not the case when its lumber goes to market. The sweet birch
log goes into the sawmill, but when the lumber goes out at the other end
of the mill, it is often simply birch having lost the adjective “sweet”
somewhere in the operation. The reason is that sweet birch and yellow
birch, quite distinct in the forest, are often mixed and become one, to
all intents and purposes, when they reach the market. That is not always
the case, but it frequently is. Something depends on the region. The
yellow birch’s range is more extensive, and in areas where it is
abundant, and sweet birch is not, it prevails in the lumber markets. But
south and southeast of the great lakes, as well as in the northeastern
part of the country, the two species mingle, and they are apt to go to
market simply as birch. The woods may be distinguished by a microscopic
examination, but the ordinary observer would make many mistakes if he
attempted to tell one from the other in the lumber yard.
The two woods are different in several physical properties. Both are
heavy, but sweet birch weighs 47.47 pounds per cubic foot, while yellow
birch weighs only 40.84 pounds, according to tests averaged by Sargent.
Yellow birch rates a little above the other in breaking strength. Both
are very stiff, but yellow birch rates superior. In most respects the
two woods are put to similar uses--flooring, interior finish,
furniture--but for some purposes sweet birch is preferred. It is
substituted oftener for cherry and mahogany, and for that reason is
known as cherry birch or mahogany birch. Its color makes the
substitution easy, and the appearance of the grain, with a little
doctoring with stains and fillers, helps in the deception. The buyer may
be deceived as to the exact kind of wood he is getting, but he is not
cheated in the quality. Birch is substituted where strength is required,
as in the rails of beds, the frames of sofas, davenports, large chairs,
and certain parts of large musical instruments. It is much stronger, and
fully as hard as cherry or mahogany, and as its appearance is so much
like them, the article is actually better on account of the
substitution. Sweet birch is largely employed for various parts of
vehicle manufacture, particularly for wagon hubs and frames of
automobiles. It is also much used in the manufacture of sleds, boats,
and handles.
The demand is heavy and the supply is diminishing. The tree is of such
slow growth that few timber owners will be inclined to wait for a second
crop, after the old trees have been cut, since 150 years are necessary
under forest conditions to produce a merchantable tree.
SONORA IRONWOOD (_Olneya tesota_) is a desert tree, and the only
representative of the genus. It takes its name from the Mexican
state where it is most abundant and where it was discovered in 1852.
It grows in southern California and Arizona, and there it thrives in
gulches and depressions in the desert, frequently associated with
mesquite. It is so heavy that perfectly dry wood will sink in water.
The heartwood is deep chocolate-brown, mottled with red, the thin
sapwood is lemon-yellow. Its hardness renders it difficult to work,
and it can scarcely be split. The wood is made into canes and other
small articles of great beauty. It is not abundant, and the small
supply is remote from manufacturing centers; otherwise it would be
more valuable. It is excellent fuel, but it is burned chiefly by
stockmen and miners in their camps. The largest trees are thirty
feet high and eighteen inches in diameter. It is an evergreen, and
its pea-like flowers brighten many a remote desert place.
WILD TAMARIND (_Lysiloma latisiliqua_) is forty or fifty feet high,
two or three in diameter, grows in southern Florida, and has
double-compound leaves, four or five inches long. The fruit is a pod
one inch wide and five or less in length. The wood weighs forty
pounds to the cubic foot, is neither strong nor tough, very low in
elasticity, is rich dark brown tinged with red, the sapwood white.
It has been reported for boatbuilding, and claims have been made
that it is equal to mahogany for that purpose, but the claim is of
doubtful validity, in view of the rather poor showing it makes in
several physical properties, though it takes good polish.
[Illustration]
YELLOW BIRCH
[Illustration: YELLOW BIRCH]
YELLOW BIRCH
(_Betula Lutea_)
There is little likelihood of mistaking the yellow birch for any other
as it stands in the woods. Its points of individuality may be discovered
on slight acquaintance, and there is little need of studying leaves,
flowers, and fruit to find ways of distinguishing this birch from other
members of the family. Its tattered, yellow and gray bark fixes it in
the memory of all who have seen it a few times. Two other eastern
birches have tattered, curling bark also, but they do not look like
this. They are the paper birch and the river birch. The former is too
white to be mistaken for yellow birch, and the river birch is too much
the color of bronze or copper. Yellow birch is named from the color of
its bark, the part which shows when the outer layers break and roll
back, disclosing the fresh, smooth, satiny layers below. Sometimes the
tree is called silver birch, gray birch, or swamp birch.
Its geographic range is bounded by a line drawn from Newfoundland to
northern Minnesota, southward through the Lake States, and along the
Atlantic coast to Delaware. It follows the Appalachian ranges of
mountains to eastern Tennessee and western North Carolina. Generally the
tree is small near the southern limit of its range. The best grows in
Michigan and Wisconsin, but it is of considerable importance in
Minnesota.
Few trees are better equipped than yellow birch to perpetuate their
species. It is an abundant seeder, and the seeds are light, winged, and
they are scattered by wind over long distances. Sometimes they are
carried miles. Of course, most of them fall in unfavorable places, and
either do not germinate or perish soon after; but they are not
particularly choice in situations, and will grow on bare mineral soil,
even in old fields, where they are flooded with sunshine, or they will
grow in deep shade where a beam of sunlight seldom touches them. They
often germinate without touching mineral soil, and take root quickly and
grow vigorously.
It is not unusual in the northern part of the tree’s range, and on high
mountains farther south, to see yellow birches standing on high,
spreading roots, two, three, or four feet above the ground. That
peculiar attitude is brought about by the manner in which the seed
begins to grow. It falls on moss which occupies the top of a log or a
stump. The moss in the deep shade retains much moisture, and the seed
germinates, grows, sends roots down the sides of the log or the stump
until they strike mineral soil, and become firmly fixed. In course of
time the log or stump decays, and the spreading roots continue to
sustain the trunk, high above the ground. This attitude of the yellow
birch tree is very common in damp woods. Occasionally the seed finds
lodgment in the moss on top of a large rock. The roots descend the sides
until they reach the ground, and as the rock does not decay, the tree
grows to maturity on the rock. The most favorable seed bed for this
species is a mass of rotten wood where a log has decayed and fallen to
pieces. Frequently such a plot is covered with yellow birch seedlings.
They have the space all to themselves, because the seeds of few trees or
plants will grow in rotten wood, unmixed with mineral soil.
The trunk of yellow birch averages a little smaller than that of sweet
birch, but may equal it in some instances. Trees reach a height of 100
feet and a diameter of three or four, but a more common size, even in
the regions of best development, is a height of sixty or seventy feet,
and a diameter of two or less.
Yellow birch was a long time coming into use. One of the first things
learned about it by early settlers in the region where it was abundant,
was that it decays quickly in situations alternately wet and dry. That
prejudiced the woodsmen against it, and they were not disposed to give
it a fair trial, as long as there was plenty of other timber. All
birches are subject to quick decay, if conditions are right to produce
it. Yellow birch in the woods sometimes dies standing, and when that
happens, the wood falls to pieces so quickly that the bark may remain
standing with very little inside of it except powder of decayed wood.
This tree is seldom mentioned in early accounts of lumber operations,
and practically never with a good word. Operators generally left it
standing when they cut the timber which grew with it.
Yellow birch is heavy, very strong, hard, light brown tinged with red,
with thin, nearly white sapwood. The color of the heartwood varies
considerably. The pores are very numerous, rather small, and are
scattered through the wood with little tendency to run in bands or
groups. The springwood blends gradually with the summerwood in a way to
make the boundaries of the annual rings somewhat indistinct. Medullary
rays are numerous, but very thin and obscure. Quarter-sawing adds little
or nothing to the appearance of the wood. It has poor figure, except an
occasional tree with wavy or curly grain, or with burls.
The wood may be readily stained. The pores hold the coloring matter
applied, and by varying the application, the appearance of the surface
can be varied. The colors of mahogany and of cherry are easily imparted,
and yellow birch often imitates those woods.
Vehicle makers choose this wood for its strength and elasticity. In the
North it is manufactured into frames for cutters and sleighs of all
kinds. It is a competitor of sugar maple for that purpose. Hubs are made
of it for horse-drawn vehicles, and its hardness gives long wear where
the spokes are inserted. That is one of the first points of failure when
a soft, inferior wood is used for hubs. The spokes work loose.
Manufacturers of automobiles have tried out yellow birch as material for
frames; it has stood the test, and is much used in competition with
other woods. The amount demanded for that purpose is not necessarily
large, but it must be the best wood that can be had.
This material reaches the markets in all grades. Large amounts are used
for packing boxes, crates, and shipping containers. Low grades answer
for these purposes, leaving the better sorts for the more exacting
industries. The logs are cut in rotary veneer for baskets, and for ply
work. Some of the veneer in three-ply is worked into commodities of high
class, such as seats and backs of theater chairs.
Birch flooring competes closely with maple for popular favor. It may
lack something of maple’s whiteness, but it takes no second place in
hardness, smoothness, and wearing qualities. It is made into parquet
flooring as well as the ordinary tongued and grooved article. As such,
the sap matches the light colored woods, and the heart the dark.
It goes into all kinds of interior house finish, from floor to ceiling,
and the finest grades are often devoted to stair work. Door and window
frames are made of it in large quantities, but it is not suited to
outside work exposed to weather, because of its tendencies to decay. It
is much employed as door material. Furniture demands the same class of
wood. Medium priced articles may be of solid birch, but the best
commodities are made of veneers laid upon other woods. Figured birch is
a favorite material for that class of work.
The more common commodities manufactured of this wood can be listed only
by groups, because of their great number. Novelties constitute a large
class. One of the earliest demands was from the manufacturers of pill
boxes, such as apothecaries use. That was before anyone had tried to
sell yellow birch in the general market, and the demand came principally
from New England and New York. Another early demand came from coopers
who found that barrel hoops of yellow birch were highly satisfactory for
certain kinds of vessels. Fish kits were among the first to appear in
birch hoops. Small saplings were used, not over two inches in diameter.
They are large enough to make two hoops by splitting. The bark was left
on, and the identity of the wood was never in doubt, because when the
sapling is of that size, the bark is a fine yellow. It has not yet
commenced to crack open and roll up, as it does later. Millions of birch
hoops are still produced yearly in the United States, but all of them
are not of this species. The hoop business has existed much more than a
century, and millions of young birches have been cut every year to meet
the demand.
Birch broom handles have been a commodity since the first lathe went to
work on that product. They are made of all the commercial birches, but
yellow birch contributes a large part. Other handles are manufactured of
it also, such as are fitted to hand saws, planes, drawing knives,
chisels, and augers.
[Illustration]
RIVER BIRCH
[Illustration: RIVER BIRCH]
RIVER BIRCH
(_Betula Nigra_)
This tree is known as red birch, river birch, water birch, blue birch,
black birch, and simply as birch. The name red birch refers to the color
of the bark which is exposed to view in the process of exfoliation. The
trunk is constantly getting rid of its outer bark, and in doing so, the
exterior layers are rolled back, hang a while, and are gradually whipped
off by the wind. The new bark which is exposed to view when the old is
rolled back is reddish. Its color varies considerably, sometimes
suggesting the tint of old brass, again it is brown, but people in
widely separated regions have seen fit to call the tree red birch
because of the color of its bark. The name black birch is not
appropriate, though the old bark near the base of large trunks may
suggest it. No reason can be assigned for calling it blue birch, unless
the foliage in early summer may warrant such a term. River birch and
water birch are more appropriate, as these names indicate the situations
where the species grows. It clings to water courses almost as closely as
sycamore. A favorite attitude of the tree is to lean over a river or
pond, with the long, graceful limbs almost touching the water.
Nature seems to recognize the tree’s habit of hanging over muddy banks,
and has prepared it for that manner of life. Seeds are ripe early in
summer when the rivers are falling. They are scattered by myriads on the
muddy shores and upon the water. Those which fall in the mud find at
once a suitable place for germination, and those whose fortune it is to
drop in the water float away with the current or they are driven by the
wind until they lodge along the shores, and the receding water leaves
them in a few days, and they spring up quickly. Before the autumn or
early winter high water comes, they are well rooted in the mud and sand,
ready to put up a fight for their lives.
The provision is a wise one. If the seeds matured in the fall, when
water is low, they would be strewn along the low shores, and before they
could take root and establish themselves, the high water and the ice of
winter would destroy them. The seeds need mud to give them a start in
life, and they need that start early in summer.
The range of river birch is less extensive than that of the other
important eastern birches, yet it is by no means limited. Its eastern
boundary is in Massachusetts, its western in Minnesota, and it adheres
fairly well to a line drawn between the two states. Its range extends
200 miles west of the Mississippi and covers most of the southern
states. It is found in an area of nearly 1,000,000 square miles, but is
scarce in most of it. In certain restricted localities it is fairly
abundant, but there are thousands of square miles in the limits of its
range which have not a single tree. Its greatest development is in the
south Atlantic states, and in the lower Mississippi basin.
Trees at their best are from eighty to ninety feet high and from two to
four in diameter, but most trunks are less than two feet in diameter.
The tree frequently forks fifteen or twenty feet from the ground, or
occasionally sends up several stems from the ground. Forms of that kind
are practically useless for lumber.
The wood is among the lightest of the birches and weighs 35.91 pounds
per cubic foot. It is rather hard, medium strong, the heartwood light
brown in color, with thick, pale sapwood. It rates below sweet and
yellow birch in stiffness, is very porous, but the pores are quite
small, and can scarcely be seen without a magnifying glass. They are
diffused throughout the entire annual ring. There is no marked
difference in the appearance of the springwood and that of the late
season. The medullary rays are very small and have little effect on the
appearance of the wood, no matter in what way the sawing is done.
The wood is apt to contain pith flecks and streaks. These are small,
brown spots or lines scattered at random through the wood. They are a
blemish which is not easily covered up if the wood is to be polished;
but they are small and may not be objectionable. The flecks are caused
by insects which, early in the season, bore through the bark into the
cambium layer (the newly-formed wood), where eggs are deposited. The
young insect cuts a tunnel up or down along the cambium layer, an inch
or less in length and a sixteenth of an inch wide. This gallery
subsequently fills with brown deposits which remain permanently in the
wood. Sometimes these deposits are sufficiently hard to turn the edge of
tools.
River birch is widely used but in small amounts. It may properly be
described as a neighborhood wood--that is, wherever it grows in
considerable quantity it is put to use, but nearly always in a local
way. For example, in Louisiana, where it is as abundant as in any other
state, it is a favorite material for ox yokes, and no report from that
state has been made of its employment for any other purpose. The reason
given for its extensive use for ox yokes there is that it is very strong
for its weight, and that it resists decay. The yokes there are usually
left out of doors when not in use, and the dampness and hot weather
cause rapid decay of most woods. The birches are usually listed as
quick-decaying woods, but the verdict from Louisiana seems to be that
river birch is an exception.
Plain furniture is made of it, and the manufacturers of woodenware find
it suitable for most of their commodities. It is sometimes listed as
wooden shoe material, but no particular instance has been reported where
it has been so used in this country. In Maryland some of the
manufacturers of peach baskets make bands or hoops of it, and pronounce
it as satisfactory for that purpose as elm.
The supply is not in much danger of exhaustion. The species is equipped
to take care of itself, occupying as it does, ground not in demand for
farming purposes. When a tree once gets a start it has a chance to
escape the ax until large enough for use.