Recreation
Management
TechTips
United States Department of Agriculture
Forest Service
Technology &
Development Program
July 2004
2300
0423 1302—SDTDC
WOOD STRANDS AS AN ALTERNATIVE TO AGRICULTURAL STRAW FOR
EROSION CONTROL
Randy B. Foltz, Research Engineer, Rocky Mountain Research Station, Moscow, ID
James H. Dooley, President, Forest Concepts, LLC, Federal Way, WA
BACKGROUND
Agricultural straw is used in forested areas of the United
States for erosion control on burned areas, harvest
landings, decommissioned road prisms, road cuts and
fills, and other areas of disturbed soil. However, an
increased agronomic and ecological value for straw; an
increased utilization for energy production, fiber panels,
and other higher value uses; a realization of the
potential of a weed and chemical residue source; and a
realization of straw as a source of allergens to workers
that handle straw have challenged the perceived
advantages of agricultural straw.
A Wood-Strand Alternative to Straw
A wood-based product that performs as well or better
than straw mulch seems to be a suitable replacement in
most applications. The benefits include use of wood
from smaller-diameter poles and species unsuitable for
other products, a more profitable use of small-diameter
timber due to the low capital cost for manufacturing
equipment and local product markets, and lower
transportation costs than agricultural straw. The woodbased product is also inherently free of noxious weed
seeds and likely to be free of pesticide residues, has a
high structural integrity, and has a zero to low probability
of producing dust or allergens during application.
A small business cooperator is developing the material
and methods for its manufacture. As shown in figure 1,
narrow veneer strips of various lengths can be blended
to produce a functional analog of straw. The
manufacturing process allows the application of
disciplined design techniques to specify length, width,
and thickness of individual components, as well as
blends.
Figure 1—Narrow strips of wood veneer used as an
alternative to straw mulch.
Design and Testing
For the initial design, two widths of strands were tested
in the Rocky Mountain Research Station rainfall
simulator laboratory. A wide group had a width of 16 mm,
while a narrow group was 4 mm wide. Both groups used
lengths of 60, 120, and 240 mm. To compare the
erosion mitigation of wood strands to that of straw, tests
employed a replicated experimental design consisting of
four soil treatments with three repetitions. The four soil
treatments were bare, straw, wide wood strands, and
narrow wood strands on a gravelly sand soil. A constant
rainfall rate of 50 millimeters per hour plus added inflow
to simulate a longer length slope produced a rain and
added inflow sequence. One soil, one 30-percent slope,
and one 70-percent cover for both the straw and the
wood strands was used. This set of treatment conditions
provided a first assessment of the potential efficacy for
the wood strand mulch materials and a baseline for
future experiments.
For additional information, contact: Recreation Management Program Leader, San Dimas Technology & Development Center,
444 East Bonita Avenue, San Dimas, CA 91773–3198; Phone 909–599–1267: TDD: 909–599–2357; FAX: (909)592-2309
LotusNotes: MailroomWOSDTDC@FSNOTES • Intranet(web site):http://fsweb.sdtdc.wo.fs.fed.us • Internet e-mail:mailroom_wo_sdtdc@fs.fed.us
Results
The two blends of wood strands were statistically equal to straw in reducing both runoff and sediment production. Both
the straw and each of the wood fiber mixes reduced erosion by 98 percent as compared to the bare soil. This result
implies that wood fibers are an acceptable alternative to agricultural straw in erosion control applications. Further work
is underway to determine optimum width and length mixes, application rates, and decomposition rates for the wood
fibers.
Table 2.2—Approximate Metric System Conversion Factors
Approximate Metric to English
System Conversion Factors
To
Change
millimeters
To
inches
Information contained in this document has been developed for the guidance of employees of
the Forest Service, United States Department of Agriculture (USDA), its contractors, and
cooperating Federal and State agencies. The USDA Forest Service assumes no responsibility
for the interpretation or use of this information by other than its own employees. The use of
trade, firm, or corporation names is for the information and convenience of the reader. Such
use does not constitute and official evalution, conclusion, recommendation, endorsement, or
approval of any product or service to the exclusion of others that may be suitable.
Multiply
by
0.03937
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