Technologies are readily available for growing hybrid poplars and willows in block plantings as short-rotation woody crops (SRWC) for fuel and fiber. SRWC species and technologies can also be incorporated into agricultural systems as agroforestry practices. Examples are windbreaks, living snowfences, “timberbelts”, riparian buffer strips, and wastewater treatment plantings. Fast growth, convenient propagation (see AF Note - 11), and compatibility with conventional farming methods make SRWC suitable for use in agroforestry practices to provide multiple benefits such as solid wood and wood fiber products, water quality improvement, crop and soil protection, wildlife habitat, and buffers for agricultural/community interfaces

Kuhn, Gary A.

Rietveld, W. J.

English

UNL | Libraries

University of Nebraska - Lincoln 
DigitalCommons@University of Nebraska - Lincoln 
Agroforestry Notes (USDA-NAC) U.S. Department of Agriculture: Forest Service -- National Agroforestry Center 
May 1998 
Opportunities for Growing Short-Rotation Woody Crops in 
Agroforestry Practices 
Gary A. Kuhn 
NRCS Agroforester, National Agroforestry Center Western Office 
W. J. Rietveld 
National Agroforestry Center, East Campus-UNL, Lincoln, NE 
Follow this and additional works at: https://digitalcommons.unl.edu/agroforestnotes 
 Part of the Forest Sciences Commons 
Kuhn, Gary A. and Rietveld, W. J., "Opportunities for Growing Short-Rotation Woody Crops in Agroforestry 
Practices" (1998). Agroforestry Notes (USDA-NAC). 9. 
https://digitalcommons.unl.edu/agroforestnotes/9 
This Article is brought to you for free and open access by the U.S. Department of Agriculture: Forest Service -- 
National Agroforestry Center at DigitalCommons@University of Nebraska - Lincoln. It has been accepted for inclusion 
in Agroforestry Notes (USDA-NAC) by an authorized administrator of DigitalCommons@University of Nebraska - 
Lincoln. 
Technologies are readily available for growing hybrid poplars and willows in block
plantings as short-rotation woody crops (SRWC) for fuel and fiber. SRWC species and
technologies can also be incorporated into agricultural systems as agroforestry prac-
tices. Examples are windbreaks, living snowfences, “timberbelts”, riparian buffer
strips, and wastewater treatment plantings. Fast growth, convenient propagation (see
AF Note - 11), and compatibility with conventional farming methods make SRWC
suitable for use in agroforestry practices to  provide multiple benefits such as solid
wood and wood fiber products, water quality improvement, crop and soil protection,
wildlife habitat, and buffers for agricultural/community interfaces. 
Poplar is the general term for trees in the genus Populus, which includes species of
cottonwoods and aspens. Cottonwoods are selected for a variety of attributes (growth,
form, adaptation to soil and climate conditions, disease/insect resistance, and intended
use) and are “crossed” to produce “hybrid” individuals. For example, P. trichocarpa
(black cottonwood), native to the Pacific Northwest, crossed with P. deltoides (eastern
cottonwood), native to the Eastern and Midwestern U.S., produces a hybrid that is
commonly grown for fiber production in the Pacific Northwest. Crosses of Populus
nigra (European black cottonwood) and Populus deltoides (eastern cottonwood), pro-
duce hybrids that are commonly used in Minnesota and the upper Midwest. Within a
hybrid, selected clones such as “robusta” and “raverdeau”are  vegetatively propagated
using “cuttings” or “whips” to establish trees in the field. Hybrid willows are a similar
situation; more than 300 clones are being screened in the Northeast for their suitability
for SRWC. 
Opportunities for income-generation from SRWC exist where both of the following
conditions exist: (1) soils and climate are favorable to produce at least 4 to 8 dry
tons/acre/year, and (2) a market exists within a reasonable distance. 
Although block plantings are the most efficient way to grow SRWC to maximize eco-
nomic gains, environmental benefits are maximized by incorporating SRWC as strip
plantings into production agriculture systems known as timber belts. These strip plant-
ings serve as conservation buffers in the farming system, and at the same time provide
additional income for the landowner. The productivity of strip-planted SRWC can be
equal to or greater than block plantings, but the enterprise will be more spread out. At
present prices, at least 30 acres of harvestable biomass must be available on a section
of farmland within 100 miles of a market in order to be economically viable. 
Plant Materials
Introduction
Opportunities for Growing Short-Rotation
Woody Crops in Agroforestry Practices
National
Agroforestry 
Center
USDA Forest Service, Rocky Mountain Research Station • USDA Natural Resources Conservation Service
1
AF Note — 10
May, 1998
Agroforestry Notes de
Opportunities in
Agroforestry
Practices
2The rotation length for SRWC is 3 to 12 years, depending on hybrid and clone, spacing,
growing conditions, and tree size desired. In many states, fiber farming is considered
agriculture and is not subject to forest practice regulations if rotations are kept under 10
to 12 years. Growing and harvesting SRWC is similar to agricultural crops in many ways,
and conventional farming equipment can be used to culture and harvest SRWC, especial-
ly if a short rotation is used. If coppicing is to be done, then harvesting is done in the dor-
mant season, which is a convenient time for farmers. The trees can regenerate by “cop-
picing”, ie., sprouting from the cut stumps. The original trees can usually withstand 3 to 4
coppice cycles, (approximately 30 years), before replanting is necessary.
Where market economics do not exist, incorporation of poplars and willows into agro-
forestry practices is mostly for conservation purposes. Poplars and willows are well-suit-
ed to many types of conservation plantings because of their fast growth, so they provide
benefits sooner. Natural Resources Conservation Service (NRCS) Plant Materials Centers
and other agencies have selected varieties for most regions of the U.S. based on their
adaptability, suitability for purpose, and lack of unwanted characteristics such as sprout-
ing or spreading. Following are some promising opportunities for incorporating SRWC
into agroforestry systems and other special applications.
Windbreaks, Living Snowfences, and Timberbelts
Cultivated varieties (cultivars) of poplars and willows have been used for many years to
protect soil, crops, and livestock. Poplar varieties like “lombardy” grow well in the
Northwest, “robusta” does well in the eastern Great Plains and Lake States, and “caroli-
na” is well suited to North-central and Northeast conditions. 
Hybrid poplars and willows may be grown as SRWC in strip plantings that also function
as windbreaks. A system of multi-row field windbreaks can be designed to provide con-
tinuous protection for cropland and also allow harvesting on a 6 to 10 year rotation.  For
example, for a 4-row windbreak on a 6/7-year rotation, two rows can be harvested after
six years and the remaining two rows after seven years when regrowth of the first two
rows is sufficient to provide crop and soil protection. If one or two rows of these multi-
row windbreaks are planted to evergreen species, the SRWC can be harvested at one
time, wildlife habitat would be enhanced, and continuous protection would be provided.
Distance between windbreaks would be determined by the average height of the trees at a
specified age in the rotation. The short harvest intervals will help maintain healthy wind-
breaks, reducing the need for costly renovation or removal of aging windbreaks. 
Living snowfences are specialized windbreaks to protect roads. Poplars and willows are
well suited for the task because of their fast growth and ability to be hedged to maintain
their size and density. If living snowfences are to be harvested, it should be done in late
winter when their snow management job is mostly over. 
Timberbelts are wide field windbreaks or field border plantings designed to increase the
SRWC component of the system. One or more rows of conifers can be incorporated to
enable harvesting of the timberbelt at one time and still provide continuous protection. 
Riparian Buffer Strips
Hybrid poplars and willows can enhance the functionality of riparian buffer strips (see
AF Note - 3) and provide income for the landowner, providing a win-win situation for
landowners and conservation. Riparian zones are “home” to poplars and willows, and
these species are ideally suited to act as “biological sponges” to absorb sediments, nutri-
ents, chemicals, and animal wastes from agricultural runoff. Riparian buffers also serve
as “waterbreaks” to slow down flood waters and intercept debris.
The width of riparian buffer strips containing SRWC can be tailored to attain
landowner objectives and conservation needs. Narrow strips attain an acceptable
level of SRWC production and conservation benefits, and minimize the amount
of land taken out of conventional agriculture. Wider strips enhance the SRWC
component with greater yield and market values likely, and are more effective in
retarding flooding.
Hybrid poplars have been tested in narrow buffer strips next to drainage ditches
within corn and soybean fields. Whips planted 4 to 5-feet deep effectively
removed excess nitrogen and phosphorus in shallow groundwater coming from
adjacent cropland. These dense plantings are winter-harvested on 1 to 3-year rota-
tions to remove the excess nutrients from the site and to rejuvenate the buffer sys-
tem. Regrowth from stump sprouting occurs rapidly, so the disturbance and
recovery period are minimal.
Similarly, wider strip plantings including SRWC can be established adjacent to
streams and rivers in agricultural landscapes. NRCS has utilized data from the
Northeast, Southeast, and Midwest to establish a riparian forest buffer standard
consisting of three vegetation zones.  Zone 1 is a minimum 15-foot wide strip
nearest the stream consisting of undisturbed native tree species. SRWC can be
grown in Zone 2. It’s width (20 feet minimum) is determined by the hydrologic
characteristics of the site, buffering needs, and the amount of land the landowner
wants to put into his SRWC enterprise. Zone 3, furthest from the stream, is a min-
imum 15’ wide band of suitable grass species. Zone 3 is optional, depending on
the need to intercept overland flow from adjacent cropland or pastureland.
Where markets exist, an alternative to SRWC is growing valuable hardwoods in
riparian zones to produce high-quality logs for lumber or plywood. 
Agricultural Wastewater Treatment
In irrigated agricultural areas, nutrient- and pesticide-laden excess irrigation
water often finds its way into rivers and streams by way of drainage ditches. A
wastewater treatment system will be tested in the Yakima Valley in the Columbia
River Basin of Washington using sediment ponds, block plantings of hybrid
poplar, and shallow wetlands to filter return flows before they reach the river. The
poplars will be harvested for fiber, thus converting a waste into a resource. 
3
Poplar trees within a riparian zone that can be harvested.
4Additional
Information
For more information contact: National Agroforestry Center, USDA Forest Service, Rocky Mountain Station\ USDA Natual Resources
Conservation Service, East Campus-UNL, Lincoln, Nebraska 68583-0822. Phone: 402-437-5178; fax: 402-437-5712.
The National Agroforestry Center is a partnership of the USDA Forest Service and the USDA Natural Resources Conservation Service. The
Center’s purpose is to accelerate the development and application of agroforestry technologies to attain more economically, environmentally,
and socially sustainable land-use systems. To accomplish its mission, the Center interacts with a national network of cooperators to conduct
research, develop technologies and tools, establish demonstrations, and provide useful information to natural resource professionals.
The United States Department of Agriculture (USDA) prohibits discrimination in its programs on the basis of race, color, national origin, sex,
religion, age, disability, political beliefs and marital or familial status. (Not all prohibited bases apply to all programs.) Persons with disabilities
who require alternative means for communication of program information (braille, large print, audiotape, etc.) should contact the USDA office
of Communications at 202-720-5881 (voice) or 202-720-7808 (TDD).
To file a complaint, write the Secretary of Agriculture, U.S. Department of Agriculture, Washington, D.C. 20250, or call 202-720-7327 (voice)
or 202-720-1127 (TDD). USDA is an Equal Employment Opportunity employer.
Community Wastewater Treatment
Block plantings of hybrid poplars can potentially be used to treat the discharge of sum-
mer effluent from a city sewage treatment plant. In Woodburn, Oregon a planned 300-
acre system of grass, clover, and poplars will be used to treat wastewater. The poplar
clones were selected from an 8-acre test planting. SRWC will be harvested on a 7 to 10
year rotation, and the income will offset a portion of the operation and maintenance costs. 
Hybrid poplars are also being tested as a “landfill cap.” In Western Oregon, a dense stand
of fast-growing poplars established on top of completed landfills reduces the amount of
rainfall  that leaches through the landfill, thereby reducing the amount of leachate from
the landfill that must be subjected to costly treatments. This approach replaces the need
for expensive synthetic membranes which are ordinarily used to cap landfills. Poplar
whips are deep-planted (2 to 4 feet) at high densities into the 5-foot deep landfill cover.
The deep rooting and fast growth of the poplars uptake the water before it leaches into
the groundwater. Poplars were found to uptake three times more water than grasses. The
trees will be managed and harvested as a SRWC.
“Biology of Populus and its Implications for Management and Conservation.” 1996.
Edited by R.F. Stettler, H.D. Bradshaw, Jr., P. E. Heilman, T. M. Hinckley. 
“Ecolotree Buffers for Controlling Nonpoint Sediment and Nitrate.” by L.A. Licht,
Schnoor, J.L., Nair, D.R.1992. In: Proceedings American Society of Agricultural
Engineers.
“High Yield Hybrid Poplar Plantations in the Pacific Northwest.” by P.E. Heilman, R. F.
Stettler, D. P. Hanley, and R. W. Carkner. 1995. Research Paper PNW 356.
Available at Washington State University, University of Idaho, and Oregon State
University Extension Offices.
“Riparian Management Systems to Protect Water Quality.” by R.C. Schultz, R.
Lowrance, W. Elmore, and Joseph P. Colletti. 1998. Chapter 7 In: Agroforestry - An
Integrated Science and Practice. W.J. Rietveld, H.E. Garrett, and R.F. Fisher (eds).
American Society of Agronomy Special Publication (In Press).
“Windbreaks and Shelterbelts in Sustainable Agricultural Systems.” by James R.
Brandle, Laurie Hodges, and Bruce Wight. 1998. Chapter 4 In: Agroforestry - An
Integrated Science and Practice. W.J. Rietveld, H.E. Garrett, and R.F. Fisher (eds).
American Society of Agronomy Special Publication (In Press).
Authors 
*Gary A. Kuhn, NRCS Agroforester, National Agroforestry Center Western Office, c/o University of
Washington, Dept. of Geological Sciences, Box 351310, Seattle, WA 98195.
W. J. Rietveld, Retired Program Manager, National Agroforestry Center, East Campus-UNL, Lincoln, NE
68583-0822.
*Primary Contact


Opportunities for Growing Short-Rotation Woody Crops in Agroforestry Practices

DigitalCommons@University of Nebraska

University of Nebraska - Lincoln DigitalCommons@University of Nebraska - Lincoln Agroforestry Notes (USDA-NAC) U.S. Department of Agriculture: Forest Service -- National Agroforestry Center May 1998 Opportunities for Growing Short-Rotation Woody Crops in Agroforestry Practices Gary A. Kuhn NRCS Agroforester, National Agroforestry Center Western Office W. J. Rietveld National Agroforestry Center, East Campus-UNL, Lincoln, NE Follow this and additional works at: https://digitalcommons.unl.edu/agroforestnotes  Part of the Forest Sciences Commons Kuhn, Gary A. and Rietveld, W. J., "Opportunities for Growing Short-Rotation Woody Crops in Agroforestry Practices" (1998). Agroforestry Notes (USDA-NAC). 9. https://digitalcommons.unl.edu/agroforestnotes/9 This Article is brought to you for free and open access by the U.S. Department of Agriculture: Forest Service -- National Agroforestry Center at DigitalCommons@University of Nebraska - Lincoln. It has been accepted for inclusion in Agroforestry Notes (USDA-NAC) by an authorized administrator of DigitalCommons@University of Nebraska - Lincoln. Technologies are readily available for growing hybrid poplars and willows in blockplantings as short-rotation woody crops (SRWC) for fuel and fiber. SRWC species andtechnologies can also be incorporated into agricultural systems as agroforestry prac-tices. Examples are windbreaks, living snowfences, “timberbelts”, riparian bufferstrips, and wastewater treatment plantings. Fast growth, convenient propagation (seeAF Note - 11), and compatibility with conventional farming methods make SRWCsuitable for use in agroforestry practices to  provide multiple benefits such as solidwood and wood fiber products, water quality improvement, crop and soil protection,wildlife habitat, and buffers for agricultural/community interfaces. Poplar is the general term for trees in the genus Populus, which includes species ofcottonwoods and aspens. Cottonwoods are selected for a variety of attributes (growth,form, adaptation to soil and climate conditions, disease/insect resistance, and intendeduse) and are “crossed” to produce “hybrid” individuals. For example, P. trichocarpa(black cottonwood), native to the Pacific Northwest, crossed with P. deltoides (easterncottonwood), native to the Eastern and Midwestern U.S., produces a hybrid that iscommonly grown for fiber production in the Pacific Northwest. Crosses of Populusnigra (European black cottonwood) and Populus deltoides (eastern cottonwood), pro-duce hybrids that are commonly used in Minnesota and the upper Midwest. Within ahybrid, selected clones such as “robusta” and “raverdeau”are  vegetatively propagatedusing “cuttings” or “whips” to establish trees in the field. Hybrid willows are a similarsituation; more than 300 clones are being screened in the Northeast for their suitabilityfor SRWC. Opportunities for income-generation from SRWC exist where both of the followingconditions exist: (1) soils and climate are favorable to produce at least 4 to 8 drytons/acre/year, and (2) a market exists within a reasonable distance. Although block plantings are the most efficient way to grow SRWC to maximize eco-nomic gains, environmental benefits are maximized by incorporating SRWC as stripplantings into production agriculture systems known as timber belts. These strip plant-ings serve as conservation buffers in the farming system, and at the same time provideadditional income for the landowner. The productivity of strip-planted SRWC can beequal to or greater than block plantings, but the enterprise will be more spread out. Atpresent prices, at least 30 acres of harvestable biomass must be available on a sectionof farmland within 100 miles of a market in order to be economically viable. Plant MaterialsIntroductionOpportunities for Growing Short-RotationWoody Crops in Agroforestry PracticesNationalAgroforestry CenterUSDA Forest Service, Rocky Mountain Research Station • USDA Natural Resources Conservation Service1AF Note — 10May, 1998Agroforestry Notes deOpportunities inAgroforestryPractices2The rotation length for SRWC is 3 to 12 years, depending on hybrid and clone, spacing,growing conditions, and tree size desired. In many states, fiber farming is consideredagriculture and is not subject to forest practice regulations if rotations are kept under 10to 12 years. Growing and harvesting SRWC is similar to agricultural crops in many ways,and conventional farming equipment can be used to culture and harvest SRWC, especial-ly if a short rotation is used. If coppicing is to be done, then harvesting is done in the dor-mant season, which is a convenient time for farmers. The trees can regenerate by “cop-picing”, ie., sprouting from the cut stumps. The original trees can usually withstand 3 to 4coppice cycles, (approximately 30 years), before replanting is necessary.Where market economics do not exist, incorporation of poplars and willows into agro-forestry practices is mostly for conservation purposes. Poplars and willows are well-suit-ed to many types of conservation plantings because of their fast growth, so they providebenefits sooner. Natural Resources Conservation Service (NRCS) Plant Materials Centersand other agencies have selected varieties for most regions of the U.S. based on theiradaptability, suitability for purpose, and lack of unwanted characteristics such as sprout-ing or spreading. Following are some promising opportunities for incorporating SRWCinto agroforestry systems and other special applications.Windbreaks, Living Snowfences, and TimberbeltsCultivated varieties (cultivars) of poplars and willows have been used for many years toprotect soil, crops, and livestock. Poplar varieties like “lombardy” grow well in theNorthwest, “robusta” does well in the eastern Great Plains and Lake States, and “caroli-na” is well suited to North-central and Northeast conditions. Hybrid poplars and willows may be grown as SRWC in strip plantings that also functionas windbreaks. A system of multi-row field windbreaks can be designed to provide con-tinuous protection for cropland and also allow harvesting on a 6 to 10 year rotation.  Forexample, for a 4-row windbreak on a 6/7-year rotation, two rows can be harvested aftersix years and the remaining two rows after seven years when regrowth of the first tworows is sufficient to provide crop and soil protection. If one or two rows of these multi-row windbreaks are planted to evergreen species, the SRWC can be harvested at onetime, wildlife habitat would be enhanced, and continuous protection would be provided.Distance between windbreaks would be determined by the average height of the trees at aspecified age in the rotation. The short harvest intervals will help maintain healthy wind-breaks, reducing the need for costly renovation or removal of aging windbreaks. Living snowfences are specialized windbreaks to protect roads. Poplars and willows arewell suited for the task because of their fast growth and ability to be hedged to maintaintheir size and density. If living snowfences are to be harvested, it should be done in latewinter when their snow management job is mostly over. Timberbelts are wide field windbreaks or field border plantings designed to increase theSRWC component of the system. One or more rows of conifers can be incorporated toenable harvesting of the timberbelt at one time and still provide continuous protection. Riparian Buffer StripsHybrid poplars and willows can enhance the functionality of riparian buffer strips (seeAF Note - 3) and provide income for the landowner, providing a win-win situation forlandowners and conservation. Riparian zones are “home” to poplars and willows, andthese species are ideally suited to act as “biological sponges” to absorb sediments, nutri-ents, chemicals, and animal wastes from agricultural runoff. Riparian buffers also serveas “waterbreaks” to slow down flood waters and intercept debris.The width of riparian buffer strips containing SRWC can be tailored to attainlandowner objectives and conservation needs. Narrow strips attain an acceptablelevel of SRWC production and conservation benefits, and minimize the amountof land taken out of conventional agriculture. Wider strips enhance the SRWCcomponent with greater yield and market values likely, and are more effective inretarding flooding.Hybrid poplars have been tested in narrow buffer strips next to drainage ditcheswithin corn and soybean fields. Whips planted 4 to 5-feet deep effectivelyremoved excess nitrogen and phosphorus in shallow groundwater coming fromadjacent cropland. These dense plantings are winter-harvested on 1 to 3-year rota-tions to remove the excess nutrients from the site and to rejuvenate the buffer sys-tem. Regrowth from stump sprouting occurs rapidly, so the disturbance andrecovery period are minimal.Similarly, wider strip plantings including SRWC can be established adjacent tostreams and rivers in agricultural landscapes. NRCS has utilized data from theNortheast, Southeast, and Midwest to establish a riparian forest buffer standardconsisting of three vegetation zones.  Zone 1 is a minimum 15-foot wide stripnearest the stream consisting of undisturbed native tree species. SRWC can begrown in Zone 2. It’s width (20 feet minimum) is determined by the hydrologiccharacteristics of the site, buffering needs, and the amount of land the landownerwants to put into his SRWC enterprise. Zone 3, furthest from the stream, is a min-imum 15’ wide band of suitable grass species. Zone 3 is optional, depending onthe need to intercept overland flow from adjacent cropland or pastureland.Where markets exist, an alternative to SRWC is growing valuable hardwoods inriparian zones to produce high-quality logs for lumber or plywood. Agricultural Wastewater TreatmentIn irrigated agricultural areas, nutrient- and pesticide-laden excess irrigationwater often finds its way into rivers and streams by way of drainage ditches. Awastewater treatment system will be tested in the Yakima Valley in the ColumbiaRiver Basin of Washington using sediment ponds, block plantings of hybridpoplar, and shallow wetlands to filter return flows before they reach the river. Thepoplars will be harvested for fiber, thus converting a waste into a resource. 3Poplar trees within a riparian zone that can be harvested.4AdditionalInformationFor more information contact: National Agroforestry Center, USDA Forest Service, Rocky Mountain Station\ USDA Natual ResourcesConservation Service, East Campus-UNL, Lincoln, Nebraska 68583-0822. Phone: 402-437-5178; fax: 402-437-5712.The National Agroforestry Center is a partnership of the USDA Forest Service and the USDA Natural Resources Conservation Service. TheCenter’s purpose is to accelerate the development and application of agroforestry technologies to attain more economically, environmentally,and socially sustainable land-use systems. To accomplish its mission, the Center interacts with a national network of cooperators to conductresearch, develop technologies and tools, establish demonstrations, and provide useful information to natural resource professionals.The United States Department of Agriculture (USDA) prohibits discrimination in its programs on the basis of race, color, national origin, sex,religion, age, disability, political beliefs and marital or familial status. (Not all prohibited bases apply to all programs.) Persons with disabilitieswho require alternative means for communication of program information (braille, large print, audiotape, etc.) should contact the USDA officeof Communications at 202-720-5881 (voice) or 202-720-7808 (TDD).To file a complaint, write the Secretary of Agriculture, U.S. Department of Agriculture, Washington, D.C. 20250, or call 202-720-7327 (voice)or 202-720-1127 (TDD). USDA is an Equal Employment Opportunity employer.Community Wastewater TreatmentBlock plantings of hybrid poplars can potentially be used to treat the discharge of sum-mer effluent from a city sewage treatment plant. In Woodburn, Oregon a planned 300-acre system of grass, clover, and poplars will be used to treat wastewater. The poplarclones were selected from an 8-acre test planting. SRWC will be harvested on a 7 to 10year rotation, and the income will offset a portion of the operation and maintenance costs. Hybrid poplars are also being tested as a “landfill cap.” In Western Oregon, a dense standof fast-growing poplars established on top of completed landfills reduces the amount ofrainfall  that leaches through the landfill, thereby reducing the amount of leachate fromthe landfill that must be subjected to costly treatments. This approach replaces the needfor expensive synthetic membranes which are ordinarily used to cap landfills. Poplarwhips are deep-planted (2 to 4 feet) at high densities into the 5-foot deep landfill cover.The deep rooting and fast growth of the poplars uptake the water before it leaches intothe groundwater. Poplars were found to uptake three times more water than grasses. Thetrees will be managed and harvested as a SRWC.“Biology of Populus and its Implications for Management and Conservation.” 1996.Edited by R.F. Stettler, H.D. Bradshaw, Jr., P. E. Heilman, T. M. Hinckley. “Ecolotree Buffers for Controlling Nonpoint Sediment and Nitrate.” by L.A. Licht,Schnoor, J.L., Nair, D.R.1992. In: Proceedings American Society of AgriculturalEngineers.“High Yield Hybrid Poplar Plantations in the Pacific Northwest.” by P.E. Heilman, R. F.Stettler, D. P. Hanley, and R. W. Carkner. 1995. Research Paper PNW 356.Available at Washington State University, University of Idaho, and Oregon StateUniversity Extension Offices.“Riparian Management Systems to Protect Water Quality.” by R.C. Schultz, R.Lowrance, W. Elmore, and Joseph P. Colletti. 1998. Chapter 7 In: Agroforestry - AnIntegrated Science and Practice. W.J. Rietveld, H.E. Garrett, and R.F. Fisher (eds).American Society of Agronomy Special Publication (In Press).“Windbreaks and Shelterbelts in Sustainable Agricultural Systems.” by James R.Brandle, Laurie Hodges, and Bruce Wight. 1998. Chapter 4 In: Agroforestry - AnIntegrated Science and Practice. W.J. Rietveld, H.E. Garrett, and R.F. Fisher (eds).American Society of Agronomy Special Publication (In Press).Authors *Gary A. Kuhn, NRCS Agroforester, National Agroforestry Center Western Office, c/o University ofWashington, Dept. of Geological Sciences, Box 351310, Seattle, WA 98195.W. J. Rietveld, Retired Program Manager, National Agroforestry Center, East Campus-UNL, Lincoln, NE68583-0822.*Primary Contact

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Opportunities for Growing Short-Rotation Woody Crops in Agroforestry Practices

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