Botanically, softwoods are gymnosperms or conifers; their
seeds are not enclosed in the ovary of the flower. Ana-
tomically, softwoods are nonporous (they do not contain
vessels). Softwoods are usually cone-bearing plants with
needle- or scale-like evergreen leaves. Some softwoods,
such as larches and baldcypress, lose their needles during
autumn or winter.
Major resources of softwood species are spread across the
United States, except for the Great Plains, where only small
areas are forested. The hardwood resource is concentrated in
the eastern United States, with only a few commercial spe-
cies found in Washington, Oregon, and California. Softwood
and hardwood species of the continental United States are
often loosely grouped in three general regions, as shown in
Table 2–1.Commercial Sources of Wood Products
Softwoods are available directly from sawmills, wholesale
and retail yards, or lumber brokers. Softwood lumber and
plywood are used in construction for forms, scaffolding,
framing, sheathing, flooring, moulding, paneling, cabinets,
poles and piles, and many other building components.
Softwoods may also appear in the form of shingles, sashes,
doors, and other millwork, in addition to some rough prod-
ucts such as timber and round posts.
Hardwoods are used in construction for flooring, architectur-
al woodwork, interior woodwork, and paneling. These items
are usually available from lumberyards and building supply
dealers. Most hardwood lumber and dimension stock are
remanufactured into furniture, flooring, pallets, containers,
dunnage, and blocking. Hardwood lumber and dimension
stock are available directly from manufacturers, through
wholesalers and brokers, and from some retail yards. Both
softwood and hardwood products are distributed throughout
the United States. Local preferences and the availability of
certain species may influence choice, but a wide selection
of woods is generally available for building construction,
industrial uses, remanufacturing, and home use.Use Classes and Trends
Major wood-based industries include those that convert
wood to thin slices (veneer), particles (chips, flakes), or fiber
pulps and reassemble the elements to produce various types
of engineered panels such as plywood, particleboard, orient-
ed strandboard, laminated veneer lumber, paper, paperboard,
and fiberboard products. Another newer wood industry is the
production of laminated wood products. The lumber indus-
try has also produced smaller amounts of railroad crossties,
cooperage, shingles, and shakes.General Technical Report FPL–GTR– 190availability in many species, sizes, shapes, and conditions to
suit almost every demand. Wood has a high ratio of strength
to weight and a remarkable record for durability and perfor-
mance as a structural material. Dry wood has good insulat-
ing properties against heat, sound, and electricity. It tends
to absorb and dissipate vibrations under some conditions
of use, and yet it is an incomparable material for musical
instruments. The grain patterns and colors of wood make
it an esthetically pleasing material, and its appearance may
be easily enhanced by stains, varnishes, lacquers, and other
finishes. It is easily shaped with tools and fastened with ad-
hesives, nails, screws, bolts, and dowels. Damaged wood is
easily repaired, and wood structures are easily remodeled or
altered. In addition, wood resists oxidation, acid, saltwater,
and other corrosive agents, has high salvage value, has good
shock resistance, can be treated with preservatives and fire
retardants, and can be combined with almost any other ma-
terial for both functional and aesthetic uses.
Timber Resources and Uses
In the United States, more than 100 wood species are avail-
able to the prospective user; about 60% of these are of major
commercial importance. Another 30 species are commonly
imported in the form of logs, cants, lumber, and veneer for
industrial uses, the building trade, and crafts.
A continuing program of timber inventory is in effect in the
United States through the cooperation of Federal and State
agencies, and new information on wood resources is pub-
lished in State and Federal reports. Two of the most valuable
sourcebooks are An Analysis of the Timber Situation in the
United States: 1952 to 2050 (Haynes 2003) and The 2005
RPA Timber Assessment Update (Haynes and others 2007).
Current information on wood consumption, production, im-
ports, and supply and demand is published periodically by
the Forest Products Laboratory (Howard 2007).
Hardwoods and Softwoods
Trees are divided into two broad classes, usually referred to
as hardwoods and softwoods. These names can be confus-
ing because some softwoods are actually harder than some
hardwoods, and conversely some hardwoods are softer than
some softwoods. For example, softwoods such as longleaf
pine and Douglas-fir are typically harder than the hard-
woods basswood and aspen. Botanically, hardwoods are
angiosperms; their seeds are enclosed in the ovary of the
flower. Anatomically, hardwoods are porous; that is, they
contain vessel elements. A vessel element is a wood cell
with open ends; when vessel elements are set one above an-
other, they form a continuous tube (vessel), which serves as
a conduit for transporting water or sap in the tree. Typically,
hardwoods are plants with broad leaves that, with few ex-
ceptions in the temperate region, lose their leaves in autumn
or winter. Most imported tropical woods are hardwoods.