PUTTING WOOD WASTE TO WORK
For many years technical studies of wood were neglected. Detailed
investigations of steel, concrete, oil, rubber and other
materials were made but wood apparently was forgotten. It has
been only during the last decade since the establishment of the
Forest Products Laboratory of the United States Forest Service,
at Madison, Wisconsin, that tests and experiments to determine
the real value of different woods have been begun. One of the big
problems of the government scientists at that station, which is
conducted in coöperation with the University of Wisconsin, is to
check the needless waste of wood. By actual test they find out
all about the wasteful practices of lumbering in the woods and
mills. Then they try to educate and convert the lumbermen and
manufacturers away from such practices.
The laboratory experts have already performed more than 500,000
tests with 149 different kinds of native woods. As a result of
these experiments, these woods are now being used to better
advantage with less waste in the building and manufacturing
industries. A potential saving of at least 20 per cent. of the
timbers used for building purposes is promised, which means a
salvage of about $40,000,000 annually as a result of strength
tests of southern yellow pine and Douglas fir. Additional tests
have shown that the red heartwood of hickory is just as strong
and serviceable as the white sap wood. Formerly, the custom has
been to throw away the heartwood as useless. This discovery
greatly extends the use of our hickory supply.
Heretofore, the custom has been to season woods by drying them in
the sun. This method of curing not only took a long time but also
was wasteful and expensive. The forestry scientists and lumbermen
have now improved the use of dry kilns and artificial systems of
curing green lumber. Now more than thirty-five of the leading
woods such as Douglas fir, southern yellow pine, spruce, gum and
oak can be seasoned in the kilns in short time. It used to take
about two years of air drying to season fir and spruce. At
present the artificial kiln performs this job in from twenty to
forty days. The kiln-dried lumber is just as strong and useful
for construction as the air-cured stock. Tests have proved that
kiln drying of walnut for use in gun stocks or airplane
propellers, in some cases reduced the waste of material from 60
to 2 per cent. The kiln-dried material was ready for use in
one-third the time it would have taken to season the material in
the air. Heavy green oak timbers for wagons and wheels were dried
in the kiln in ninety to one hundred days. It would have taken
two years to cure this material outdoors.
By their valuable test work, scientists are devising efficient
means of protecting wood against decay. They treat the woods
with such chemicals as creosote, zinc chloride and other
preservatives. The life of the average railroad tie is at least
doubled by such treatment. We could save about one and one-half
billion board feet of valuable hardwood lumber annually if all
the 85,000,000 untreated railroad ties now in use could be
protected in this manner. If all wood exposed to decay were
similarly treated, we could save about six billion board feet of
timber each year.
About one-sixth of all the lumber that is cut in the United
States is used in making crates and packing boxes. The majority
of these boxes are not satisfactory. Either they are not strong
enough or else they are not the right size or shape. During a
recent year, the railroads paid out more than $100,000,000 to
shippers who lost goods in transit due to boxes and crates that
were damaged in shipment.
In order to find out what woods are best to use in crates and
boxes and what sizes and shapes will withstand rough handling,
the Laboratory experts developed a novel drum that tosses the
boxes to and fro and gives them the same kind of rough handling
they get on the railroad. This testing machine has demonstrated
that the proper method of nailing the box is of great importance.
Tests have shown that the weakest wood properly nailed into a
container is more serviceable than the strongest wood poorly
nailed. Better designs of boxes have been worked out which save
lumber and space and produce stronger containers.
Educating the lumbering industry away from extravagant practices
is one of the important activities of the modern forestry
experts. Operators who manufacture handles, spokes, chairs,
furniture, toys and agricultural implements could, by scientific
methods of wood using, produce just as good products by using 10
to 50 per cent. of the tree as they do by using all of it. The
furniture industry not infrequently wastes from 40 to 60 per
cent. of the raw lumber which it buys. Much of this waste could
be saved by cutting the small sizes of material directly from the
log instead of from lumber. It is also essential that sizes of
material used in these industries be standardized.
The Forest Products Laboratory has perfected practical methods of
building up material from small pieces which otherwise would be
thrown away. For example, shoe lasts, hat blocks, bowling pins,
base-ball bats, wagon bolsters and wheel hubs are now made of
short pieces of material which are fastened together with
waterproof glue. If this method of built-up construction can be
made popular in all sections of the country, very great savings
in our annual consumption of wood can be brought about. As
matters now stand, approximately 25 per cent. of the tree in the
forest is lost or wasted in the woods, 40 per cent. at the mills,
5 per cent. in seasoning the lumber and from 5 to 10 per cent. in
working the lumber over into the manufactured articles. This new
method of construction which makes full use of odds and ends and
slabs and edgings offers a profitable way to make use of the 75
per cent. of material which now is wasted.
The vast importance of preserving our forests is emphasized when
one stops to consider the great number of uses to which wood is
put. In addition to being used as a building material, wood is
also manufactured into newspaper and writing paper. Furthermore,
it is a most important product in the making of linoleum,
artificial silk, gunpowder, paints, soaps, inks, celluloid,
varnishes, sausage casings, chloroform and iodoform. Wood
alcohol, which is made by the destructive distillation of wood,
is another important by-product. Acetate of lime, which is used
extensively in chemical plants, and charcoal, are other products
which result from wood distillation. The charcoal makes a good
fuel and is valuable for smelting iron, tin and copper, in the
manufacture of gunpowder, as an insulating material, and as a
clarifier in sugar refineries.
It is predicted that the future fuel for use in automobile
engines will be obtained from wood waste. Ethyl or "grain"
alcohol can now be made from sawdust and other mill refuse. One
ton of dry Douglas fir or southern yellow pine will yield from
twenty to twenty-five gallons of 95 per cent. alcohol. It is
estimated that more than 300,000,000 gallons of alcohol could be
made annually from wood now wasted at the mills. This supply
could be increased by the use of second-growth, inferior trees
and other low-grade material.