VIABLE SUBSTITUTE FOR WOOD
lumber prices, decreasing supplies and environmental concerns
are all cited as reasons straw-based building products are
in demand. Straw is a renewable resource capable of relieving
pressure on timber. Trees are harvested for wood but barley
and wheat for grain. Straw is a by-product. But an ever-increasing
population nevertheless demands more wood. This inevitably
leads to regional wood shortages manifested in a general
rise in wood costs. Straw as a new fiber source can substitute
for wood, thereby preserving forests.
new companies start up to meet this demand, farmers in some
areas have a market for their straw. Some in the building
industry see straw as a viable and near perfect alternative
to wood: it is abundant, renewable and inexpensive. North
American farmers produce an estimated 150 million tons of
straw each year as a by-product of the continent's massive
cereal grain harvest. Many growers would love to have a
market for straw because it can be a disposal problem. The
raw material is obviously there, but the ultimate success
of the new industry will depend on the performance of the
how does it do as a building product? It is durable, a good
insulator and resists moisture and rot. Straw's greatest
potential as a building material today seems to be as "strawboard"-straw
pressed under intense heat and pressure to create a fiberboard.
Naturally occurring resins in the straw, under pressure,
bond it into a hard wood-like material. The resulting straw
fiberboard (or particleboard) is used as floor underlay,
cabinets, trim, siding, furniture and structural insulating
panels. A house made using structural fiberboard panels
requires 85 percent less timber than a conventional wood-frame
the new straw building industry eventually uses just 25
percent of the known available supply of straw, about 37.5
million tons, it would be enough to provide structural panels
(exterior wall, roof, interior partitions and floors) for
one million two-story houses every year. According to industry
spokesmen, that's nearly 2.2 billion square meters of straw
particleboard. The projected figure is four times the current
total of the U.S. production.
is in common use in all types of building construction:
wall and floor panels, doors, furniture and cabinetry. Wheat
straw particleboard is made from wheat straw, a waste product
from wheat farming bound together with resin. Bales of wheat
straw are milled into fine particles, sorted and dried,
and then bound together with a formaldehyde-free resin.
The particles are then hot-pressed into sheets of the desired
thickness. The sheet is sanded and cut to required sizes.
of the primary advantages of this product is that the resin
which binds the straw fibers together is formaldehyde-free,
and is thus free of harmful emissions, both in use and in
manufacture. The main ingredient-wheat straw-is a low-cost
waste product; its use provides a second income to farmers
and it is readily available and accessible.
Benefits of Straw Removal
soil temperature in spring,
soil dryout in summer,
to low-till or no-till farming,
combine operating costs,
risk of disease and insect transfer to next season.
of carbon from decaying straw into the air contributes
to global warming through greenhouse effect. Straw-based
panels sequester carbon, thus eliminating this contribution
to global warming.
straw removal has no effect on soil tilth in Black soils.
For Grey soils, straw needs to be returned to the soil
described in this fact-sheet were presented by numerous
speakers during a seminar held in St. John, WA on June 12,
1997. Prepared by John D. Fouts, WSU Cooperative Extension.
Sustainability. Highlights from a seminar series conducted
by Washington State University's Ag Horizons Team and funded
by USDA Western Region SARE.
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