Design Solutions - Spring 2024 - 56

In hardwoods, if this transition from
earlywood to latewood is abrupt the
species is classified as ring porous.
If there is not a distinct difference in
cell cavity size the species is classified
as diffuse-porous (larger and smaller
cell cavities mixed throughout the
growing season). Examples of ringporous
woods are Ash, Grey and Red
Elm, Hickory, Red Oak and White Oak.
Diffuse-porous examples include
Basswood, Beech, Birch, Butternut,
Cherry, Hard and Soft Maple, Poplar,
and Walnut.
The distinction between ring and
diffuse porous has significant visual
impact on the appearance of the wood
and how it takes a finish. Earlywood
tends to absorb finishes more than
latewood, leading to a darker and
lighter ring pattern in ring-porous
woods, and a blotchy stain finish to
diffuse-porous
woods. Diffuseporous
woods take
a natural finish
well. Trees grown in
northern latitudes or
dense timber stands
tend to have narrow
growth rings.
The properties of some species
make them better for utility purposes
and not as finished woodwork.
An example is Poplar, which is a
moderately stable wood but has
color variations from cream to green,
purple, and dark brown/black.
Poplar paints well but does not stain
well. Cottonwood, while having
good fastener holding properties is
dimensionally unstable and fuzzes
significantly when machined. For some
uses, the density of the wood may
influence your choice. For instance, in a
high traffic setting Hard Maple or White
Oak would be better flooring choices
than Walnut. In free standing use, the
natural stability of a species may be
more important to prevent warping or
twisting. A great resource for properties
of the most utilized wood specie is a
USDA Forest Service Forest Products
Laboratory book, " Wood Handbook:
Wood as an Engineering Material " ,
56 designsolutions I spring 2024
available free at https://www.fpl.fs.usda.
gov/documnts/fplgtr/fpl_gtr190.pdf.
CUTTING LUMBER
The annual rings of growth are used
to describe the orientation from which
boards are cut from a log. If the face of
the board is cut tangent to the annual
rings, it is called plain sawn. If the face of
the board is cut so that it is radial to the
growth rings, and parallel to the wood
rays, it is quarter sawn. Quarter and rift
sawn give a straight grain appearance
to the board, like someone ran a
comb down the length of the board.
The separation of rift and quartered
only occurs in White Oak and Red Oak
because of their larger wood rays.
In species with large wood rays,
cutting parallel to them gives the
sought after distinctive ray flash. The
grain angle relative to the wide face of
the board is the best way to distinguish
the grain patterns. Plain sawn will
have grain angles of 0 -45 degrees and
quarter sawn will have grain angles of
45-90 degrees. There is some crossover
in the 30-60-degree range that will
give a grain pattern often referred to as
bastard sawn (not quite plain and not
straight as quartered). In Red and White
Oak, an angle of 45-60 degrees yields
a rift pattern (with no wood ray fleck)
and 60-90 degrees a truer quartered
pattern (light to heavy ray fleck).
HARDWOOD AVAILABILITY
The availability of North American
hardwoods is generally good. But
if you are looking at a project with
large amounts of a single specie
then additional time may be required
to accumulate enough material.
Fluctuations in demand for the lower
grades (#1, #2, and #3 Common) of
some species means less availability
of the upper grade for architectural
woodwork. The warm winters in
many hardwood growing regions have
reduced harvesting seasons because
the ground is too soft to run heavy
equipment. For Birch and Maple there
has been a return to the old practice
of processing when the trees are not
actively growing which yields whiter
material. Invasive insects are impacting
some species, such as the Emerald Ash
Bore killing large areas of Ash trees.
North American hardwoods are one
of our great renewable resources. When
specified correctly they can add warmth,
beauty, and character to an architectural
project. During the design stage, it is
cost and time efficient to work with an
AWI woodworker or material supplier
to take advantage of their expertise to
better utilize North American hardwoods
to enhance your project.
Long-time AWI Treasurer Skip Heidler
is the fourth-generation co-owner of
Heidler Hardwood Lumber Company,
Chicago, where he has worked since
1981. A family business incorporated
in 1903 now employs its fifth
generation. He is a National Hardwood
Lumber Association Inspection School
graduate and served as president of
the Hardwood Distributors Association
from 1993-1994. His service to AWI
includes AWI Chicago Chapter Board
of Directors as well as the AWI
National Board of Directors, Marketing
Committee Chair, Tech Committee
member for Quality Standards 8,
Finance Committee Chair and Audit
Committee Chair. Heidler holds a BS
in Wood Science and Technology
from Colorado State University.
https://www.fpl.fs.usda.gov/documnts/fplgtr/fpl_gtr190.pdf https://www.fpl.fs.usda.gov/documnts/fplgtr/fpl_gtr190.pdf
Design Solutions - Spring 2024

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