Agroforestry

These aren’t your 

grandfather’s shelterbelts

VOLUME 20 ISSUE 1 Inside

WINDBREAKS

As we consider the role of windbreaks in today’s agriculture we need 

to reflect on the roots of windbreak application in North America. The 

first thing we notice is that windbreaks were commonly called shelterbelts because they provided shelter from the wind. Protection for 

homes, livestock and soil drove the demand for shelterbelts. In this 

day of well-insulated homes, climate-controlled tractors and confined 

animal feeding operations the call for shelter isn’t as apparent as it 

once was. Replacing the need for shelter are air and water quality, 

wildlife habitat, crop quality and additional income. Gone are the 

10-15 row shelterbelts. Research on windbreak density tells us that 

depending on the need, sometimes only one, two or three rows are 

necessary. Take a look inside and see what windbreaks are doing for 

agriculture today. ]

3

8

Protecting

organic crops

Varied weather

causing

Windbreaks

designed with

pollinators

in mind

Inside

11
Info sheets Living Snow Fence

2 Inside Agroforestry ] Volume 20, Issue 1

NAC Director’s Corner

A commentary on the status of agroforestry by Andy Mason, NAC Director

Windbreaks: Is an old practice ready

to take on 21st Century challenges?

Windbreaks are America’s oldest agroforestry practice (at least on the U.S. mainland), but is agroforestry’s 

“veteran” ready to take on today’s challenges? The answer is 

unequivocally yes! 

However, before looking forward, let’s reflect on the benefits provided by the many thousands of miles of windbreaks 

that have been established since the 1930s. Those windbreaks 

have — and in many cases continue to — reduce soil erosion, 

protect crops and livestock, make farmsteads more livable 

for people and more. If you haven’t already, I recommend 

you read “The Worst Hard Time,” by Timothy Egan. Egan’s 

accounting of the so-called Dirty Thirties, told by survivors of 

that very difficult time, also chronicles Hugh Hammond Bennett’s success in awakening America to the importance of soil 

conservation. As a result, the Soil Erosion Service was created 

in 1933, then the Soil Conservation Service in 1935, and, in 

1994, the Natural Resources Conservation Service. 

Although established earlier (1905), the U.S. Forest Service 

also was an important conservation player in the Dust Bowl 

region. Through the Prairie States Forestry Project (1935-

1942), the Forest Service worked with the Works Progress 

Administration and Civilian Conservation Corps throughout 

the Great Plains to establish 18,600 miles of windbreaks. 

The scientific basis for those first rows of trees established 

during the Dust Bowl years has certainly been substantiated 

in the last 60-plus years. We know that properly planned, 

established and managed windbreaks provide the most basic 

protection and conservation functions on the farm and ranch, 

and can even help keep roads and highways clear of snow 

for safer travel. But we are learning how we can derive even 

more services from this practice by creating more innovative windbreak designs that can help tackle odor mitigation, 

build habitat for pollinators and other critters, support organic 

agriculture, augment biofuel production and make landscapes 

more resilient to climate change. These proven ‘old’ and 

potential ‘new’ uses of windbreaks are explored in this issue 

of “Inside Agroforestry.” As we usher in the ‘new,’ please 

remember that those ‘old’ uses of windbreaks are still just as 

important today!

How have windbreaks helped provide economic, environmental and social benefits in your community/region? I 

encourage you to tell us your stories and perspectives about 

windbreaks. Please email them to me at amason@fs.fed.us

Sincerely,

Andy Mason

NAC has added a new 

product in the Working Trees 

family of publications, Working Trees Info. We call them 

Info sheets because they 

are a single page, front and 

back. Just enough room to 

highlight a single issue or 

benefit that an agroforestry 

practice can address or 

provide. The Info sheets will 

be available in larger quantities for your office display, 

landowner meetings, and 

county fairs. The first few

Info sheets will be general 

information on each agroforestry practice. 

Future topics will cover 

income, energy, air quality, 

well, you get the idea. 

Those of us in the northern 

U.S. are in the middle of 

winter, which means snow 

is a frequent topic of conversation. A new brochure 

from the Working Trees series 

is headed your way, “Living 

Snow Fence.” Like all the 

other editions from the Working Trees series, this isn’t a 

how-to-design publication, 

but can be used as a tool 

to talk to people about the 

benefits and basics of living 

snow fences. ]
Five generations ago the Huenefeld 

family began farming near Aurora, 

NE. The family also began planting 

windbreaks to protect its homes, livestock, 

crops and the sandy soil of the Platte River 

valley. 

Wes Huenefeld, born in 1909, said 

that when he was younger many people 

lost their farms because of drought and 

erosion. But his father managed to hold 

onto their farm, at least in part, because of 

their trees that kept the land from eroding. 

In 1948, Wes began planting windbreaks 

extensively on the farm and, in 1959, 

the Huenefeld farm was recognized as 

Nebraska’s first Tree Farm in the national 

recognition program.

Farming, conservation and windbreaks 

are a part of the fabric of the Huenefeld 

family. Wes’s nephews Paul and Dan 

Huenefeld are firm believers in the value 

of windbreaks. Paul says that in the 1980s 

his children were young and he began to 

think about farming differently “after it 

dawned” on him that he wouldn’t let his 

children play in the field soils when they 

brought lunch out to him. His concern 

for his children coming into contact with 

pesticides and fertilizers grew to include 

similar concerns for his farm, the environment and the crops that he grew and sold. 

While it took more than a decade to 

certify Paul’s and Dan’s crop fields for 

organic farming, now seven quarters

of Huenefelds’ section are certified organic. They raise corn, soybeans, alfalfa, 

hay, popcorn and wheat.

Paul says, “Organic farming and trees 

fit like a hand and a glove to work as a 

buffer.” 

For a crop to be certified as organic 

one of the requirements is that it must 

be protected from off-site contamination 

of prohibited pesticides and fertilizers. 

Windbreaks can provide that necessary 

protection, particularly from aerial drift of 

pesticides. 

Mace Vaughan, Pollinator Program 

Director for the Xerces Society, says, 

“A pollinator-safe drift barrier is one 

composed of evergreens, with good 

density (around 50 percent), a couple of 

rows wide, and around 15 feet tall. Good 

evergreens include firs, spruce, junipers, 

or arborvitae because these don’t open 

up, like pines can, when they get older.” 

Mace added that the needles are better at 

grabbing droplets from the air than are 

broadleaves.

Paul Huenefeld said that windbreaks do 

more than slow the wind and buffer his 

organic crops from undesirable drift. 

“We also appreciate the habitat for 

insects and insect predators. Along with 

grass and legumes (trees) produce habitat 

for wildlife,” Huenefeld said. “Organic 

farming is working in harmony with nature. It’s fascinating and something we’ll 

never fully understand,

“We can be good producers and good 

stewards of the land because it is a good 

place to be.” ]

Trees protecting organic crops

Richard Straight

Lead Forester 

National Agroforestry Center 

Lincoln, NE

Inside Agroforestry ] Volume 20, Issue 1 3

Above: A windbreak planted by Wes Huenefeld protects a field where organic corn is grown. 

Below: Paul Huenefeld (right), Wes Huenefeld, (center), and Paul’s son, James (left), stand in 

amongst Nebraska’s first Tree Farm. Photos: Richard Straight

Adapted from “Organic Agriculture 

Heats Up” by Randy Gunn, South Central Nebraska RC&D and Joanna Pope, 

NRCS Public Affairs Specialist

A sign on the Huenefeld farm tells a small part 

of the story behind the Huenefeld farm near 

Giltner, NE. Photo by Richard Straight
4 Inside Agroforestry ] Volume 20, Issue 1

No one likes to drive on a snow covered highway and state highway transportation departments don’t like the high costs 

of plowing roads to keep them open. That is what Craig Ziegler, 

then NRCS State Staff Forester, thought when contacted about 

the opportunity to establish a living snow fence.

In the winter of 2002-2003, Craig, was contacted by Gary 

Kuhn, now retired NRCS Agroforester, located in Spokane WA, 

attached to the National Agroforestry Center (NAC) in Lincoln, 

NE. NAC was looking for possible demonstration projects to 

increase the visibility of living snow fences to the public, and 

it had some grant money that could be used to establish the 

demonstration project. To be seen by the public the living snow 

fence needed to be near a paved road, so it seemed appropriate to 

contact some city, county or state highway offices for interest. 

Kuhn and Zeigler met with the Pendleton office of the Oregon 

Department of Transportation (ODOT) in April 2003 and gave a 

presentation to the ODOT personnel on the use and effectiveness 

of living snow fences. After the presentation Kirk Locke, Transportation Maintenance Coordinator, asked for some time to identify some possible locations to look at later. In July, NRCS and 

ODOT staff looked at several sites and agreed on a location near 

Athena, OR. The site was a deep silt loam soil so the trees were 

anticipated to grow quite rapidly. The living snow fence would 

stretch for 2,900 feet paralleling Highway 11 and was located 

150 feet from the highway, on the windward side. This stretch of 

highway receives snow that comes off the Blue Mountains to the 

east, blowing for many unobstructed miles. 

The next step was to remove the existing snow fence structure 

so the site could be readied for planting. To ensure seedling survival, deep ripping the soil to break up any root restricting layers 

was completed during the fall of 2004 with smoothing completed 

by disking prior to planting. ODOT selected a contractor to finish 

the disking, lay down the weed barrier fabric and plant the tree 

seedlings.

In March 2005, the contractor completed the planting. The 

2,900-foot strip was disked first and then a 12-foot wide weed 

barrier fabric was installed. 

It was agreed to install a two-row, high-density windbreak. The 

design called for trees to be planted using a six-foot by six-foot 

spacing (six feet between the trees and six feet between the rows) 

and two feet in from the edge. The two rows would be offset 

by three feet, so gaps would be minimized as the trees filled in. 

Rocky Mountain juniper was selected to be planted due to their 

compact upright growth form, drought hardiness and their ability 

to withstand slight amounts of herbicide overspray. 

The juniper seedlings were hand planted. L-shaped slits were 

made in the weed barrier and the seedling was planted. A little 

pre-emergent herbicide was applied and then the flap (created for 

the planting) was put back and two long staples were installed to 

hold the flap down.

A random sample of seedling height measurements showed an 

average height of 11 inches just after planting. In 2006, near the 

end of the second growing season, the trees averaged about two 

and half feet tall (range just under two feet to four feet). 

By the end of the third growing season the trees averaged 

height was three and half to four feet (a range of three feet to 

more than six feet). The widths were filling in but not as fast as 

height growth. There were still gaps, but the junipers averaged 

two to four feet in width. It was expected to take 5-7 years before 

being fully functional in catching and holding blowing snow. 

In the fall of 2011, the living snow fence was visited and evaluated. Seven growing seasons had passed and the junipers had 

grown well. The heights of the trees ranged from six to 10 feet 

with eight to nine feet being the average. The tree widths were 

four to six feet, averaging four to five feet.

The gaps between the trees have filled in and the living snow 

fence is fully functional. It should capture snow for many years. ]

Working trees keep the roads clear

Craig Zeigler

Forester, West National Technology Support Center,

NRCS

Portland, OR

Rocky Mountain juniper after 7 years of growth are filling in and should be 

capable of catching and holding blowing snow. Photo by Craig Zeigler

Rocky Mountain junipers were planted to make a living snow fence in 

Oregon. Photo by Craig Zeigler
 Volume 20, Issue 1 ] Inside Agroforestry 5

National Agroforestry Center

Update 2011

The USDA National Agroforestry Center (NAC) Update highlights annual accomplishments of NAC products, programs and projects. 

For a complete summary of NAC 2011 accomplishments and activities or for more information visit www.unl.edu/nac or contact the 

Center at 402-437-5178 extension 4011.

A Partnership of the Forest Service and Natural Resources Conservation Service

Technology Transfer

Tribal Agroforestry Initiative 

As a result of the new Tribal Partnership initiative, NRCS Agroforester Doug 

Wallace and FS Agroforester Rich Straight worked closely with the Indian Nations Conservation Alliance (INCA), and FS and NRCS Tribal Relations staff, 

to develop a nationwide survey of the Tribal Conservation Districts (TCD). 

INCA and NAC will use results at a future workshop with Tribal Conservation 

Districts.

“NEW” Working Trees Pop Up Banners

NAC developed two new, free standing, vertical display banners (40”W x 

90”H) for promoting agroforestry for use by partners – Working Trees for 

Wildlife and Working Treesfor Water Quality. These and the other banners are 

available on a first-come, first-serve basis. Displays and banners are shipped 

free of charge. The only cost is shipping it back to NAC or to the next user. 

For more information contact FS Information Specialist Steve Hermann at: 

slhermann@fs.fed.us

First National Webinar on Silvopasture

FS Agroforester Rich Straight assisted with NAC’s first national webinar. The 

webinar was produced through the North Carolina State Extension system. 

Terry Clason, NRCS Louisiana State Forester, was the featured speaker with 

his presentation, “Silvopasture: a Viable Agroforestry Enterprise System.” Rich 

also presented an overview of NAC silvopasture resources. A total 347 people 

from across the nation participated in the hour-long webinar. 

2012 Census of Agriculture 

will include Agroforestry Question

Based on a request by NRCS Chief Dave White to the National Agricultural 

Statistics Service (NASS), NRCS Agroforester Doug Wallace coordinated with 

NASS to add an agroforestry question for the 2012 Census of Agriculture. This 

will be the first direct agroforestry question ever used in a Census of Agriculture national survey. The survey question asks, “At any time during 2012, did 

this operation practice alley cropping or silvopasturing as an integrated agroforestry system?”

Windbreak Innovation/Renovation Training and Workshops

NAC is partnering with Agriculture and Agri-Food Canada, Agroforestry Development Centre to develop a series of training workshops on windbreak renovation & innovation in Canada and the U.S. Great Plains. The workshops’ aim 

is to bring together resource professionals in Canada and the U.S. to learn about 

the latest science and technology of windbreak rejuvenation and innovation.

“USDA Agroforestry Strategic 

Framework” Completed 

Director Andy Mason led an Interagency 

Agroforestry Team (IAT) to develop a first-ofits-kind national strategic framework for agroforestry. The new five-year plan will increase 

awareness of agroforestry as a means to accomplish USDA’s highest priorities, identify the 

Department’s future emphasis areas in agroforestry research and development and technology 

transfer, as well as help guide NAC’s future 

direction. NAC provided significant support to 

the IAT, which includes representatives from 

five USDA agencies (FS, NRCS, Agricultural 

Research Service, National Institute of Food 

and Agriculture, and the Farm Service Agency) 

and two key partners (National Associations of 

State Foresters and Conservation Districts).

NAC Recognized for 

Accomplishments and Collaboration

NAC received “special recognition” as an 

exemplary collaborative case study at the 

March 15, 2011, Roundtable event at the 

American Association for the Advancement of 

Science headquarters in Washington, DC. The 

recognition was based on NAC’s significant 

record of agroforestry research and technology 

transfer accomplishments and the long-standing partnership between the Forest Service and 

the Natural Resources 

Staff Update

Steve Hermann joined NAC as the Forest 

Service Information Specialist in July 2011. 

Doug Wallace, Natural Resources Conservation Service Agroforester at NAC, retired in 

October 2011.
6 Inside Agroforestry ] Volume 20, Issue 1







The USDA National Agroforestry Center (NAC) is a partnership of the Forest Service (Research & Development and State & Private Forestry) and the Natural Resources Conservation Service. It is administered by the Forest Service, Southern Research Station. NAC’s staff are located at Lincoln, NE and in Blacksburg, VA. NAC’s purpose is to accelerate 

the development and application of agroforestry technologies to attain more economically, environmentally, and socially sustainable land use systems. 

USDA Policy prohibits discrimination because of race, color, national origin, sex, age, religion, or handicapping condition. Any person who believes he or she has been discriminated against in any USDA-related activity should immediately contact the Secretary of Agriculture, Washington, DC 20250. 

Update 2011

Research

The Global Research Alliance Addresses Agroforestry 

Research Program Leader Michele Schoeneberger continues to work with 

the Croplands Group of The Global Research Alliance and bring agroforestry science to the group, which is focused on bridging gaps in research 

on agricultural greenhouse gas emissions. The Alliance was launched at 

the Copenhagen Climate Summit in December 2009.

Targeting Installation of Riparian Forest Buffers 

Research Riparian Ecologist Mike Dosskey is working with colleagues 

at the New Jersey Institute of Technology, Iowa State University and the 

University of Nebraska to complete improvements on a tool for that identifies the most effective sites within a watershed for conservation buffers, 

thereby improving the overall cost-effectiveness of a project. NAC GIS 

Specialist Todd Kellerman is providing geospatial technical assistance for 

model development and evaluation.

Soil & Water Conservation Society Recognizes 

NAC Scientist 

Research Program Leader Michele Schoeneberger was one of the recipients of the Soil and Water Conservation Society’s 2011 Editor’s Choice 

Award on a paper she coauthored titled “Carbon Sequestration in Agricultural Lands of the United States.” This article appeared in the 2010 

“Journal of Soil and Water Conservation” (65:6A-13A).

12th North American Agroforestry Conference

NAC provided planning and financial support for the conference, June 

4-9, 2011 in Athens, GA, as well as numerous presentations, posters and a 

booth. A highlight of the conference was the unveiling of the new “USDA 

Agroforestry Strategic Framework” by Deputy Secretary of Agriculture 

Kathleen Merrigan.

New Translation of Buffers Guide

The “Conservation Buffer Guide” by Research 

Landscape Planner Gary Bentrup is now available 

in French. The French version was funded and 

printed by the Canadian Agroforestry Development 

Centre. Conservation Buffers: Design Guidelines 

for Buffers, Corridors, and Greenways provides 

over 80 illustrated design guidelines synthesized 

and was developed from a review of more than 

1,400 research publications.

English, Spanish and Chinese versions are 

available for order as a spiral-bound field guide. 

Downloadable PDFs in French, Spanish, Simplified Chinese and Korean translations are available 

at: www.unl.edu/nac/bufferguidelines/index.html 

NAC Scientist Receives 

Civil Rights Award

Jim Chamberlain, a research forest products 

technologist, was chosen as the 2011 Forest Service (FS) Southern Research Station Civil Rights 

Award recipient for making outreach a core objective within his Non-timber Forest Products research 

program. Jim used outreach as a vehicle to provide 

research and FS experiences to a diversity of audiences – from faculty to students to current natural 

resource professionals.

FY2011

Argentina 

Brazil

Cameroon

Canada

Chile

China

Ecuador

England

Finland

France

Great Britain

Hungary

India

Israel

Malaysia

Mauritius

Mexico

Nigeria

Pakistan

Paraguay

Peru

Philippines

Portugal

Rep.Dominicana

South Africa 

Spain

Switzerland

Western Australia

Requested Publications

29 countries and 50 states, including Puerto Rico and 

the Virgin Islands were served.

Working Trees Series Quantity Agriculture/Spanish 3,794

 Communities 2,724

 Livestock/Spanish 2,440

 Livestock-SE/Spanish 196

 Silvopasture 2,714

 Wildlife 4,354

 Treating Waste 0

 Water Quality 3,744

Windbreak Series (set of 11) 4,075

Windbreaks for Conservation 351

Miscellaneous 3,567

Conservation Buffer Guide 846

Conservation Buffer Guide/Spanish 210

Conservation Buffer Guide/Chinese 353

CanVis 110

Total Worldwide 30,743
Most people are familiar with the old cliché, “you can’t see 

the forest for the trees.” But is it possible to say, “you can’t 

smell the pigs for the trees?” 

In 2006, the idea of using windbreaks to help mitigate offsite 

impacts of a confined animal feeding operation (CAFO) was a 

new concept in northeast Missouri. Kent Ensor, owner of Z-Base 

Farms in Monroe County, liked the idea and thought it would 

help show his neighbors that he was listening to their concerns 

regarding a planned expansion of his swine operation. Ensor 

pursued assistance through the Natural Resources Conservation 

Service (NRCS) and was approved for an Environmental Quality Incentives Program (EQIP) contract that provided financial 

assistance for site preparation and tree planting and an incentive 

payment to establish the windbreak. 

Kent and Kristy Secrease, who worked for Ensor on the farm, 

began planting trees within days of receiving the windbreak 

planting plan. The plan called for establishing hybrid willows, 

Norway spruce and ninebark in strategic locations around four 

existing buildings and a planned pig nursery. The windbreak concealed the facility and altered ground level winds. The result was 

dilution and dispersion of odorous gases through a mixing effect 

and interception and deposition of odorous dusts and aerosols in 

and around the trees. 

Since the Z-Base windbreak was one of the first established for 

the purpose of reducing odors associated with a livestock production facility in the state, it has been visited several times as an 

example for training NRCS staff, partners and other cooperators. 

Sadly, Kent and Kristy lost their lives in a tragic tornado in 

October 2007. Ensor’s son Aaron took over operation of the 

farm with a helping hand from his friend, Tom Secrease, Kristy’s 

brother. Both see benefits from the now five-year-old windbreak. 

“When the willows are fully leafed out, you can hardly see the 

buildings from the west,” Aaron Ensor said. “Numerous neighbors have commented on the looks, and a few have said they 

noticed a definite reduction of odor at their house.”

 Other hog producers have inquired about the trees and shrubs 

and the associated benefits, but Aaron is not sure if they have 

made the next step of planting their own windbreaks.

“The company that we grow gilts for will often bring their 

buyers by our place to show them what they are buying,” Ensor 

said. “I think part of the reason they come here is due to how the 

facility looks because of the trees.”

Darren Hoffman, Resource Conservationist at the Monroe 

County NRCS field office, said that he has received a lot of questions from livestock producers regarding technical and financial 

assistance for establishing trees around their buildings. He credits 

part of this to the success of the planting at Z-Base. “It’s been a 

good selling point for us when working with other producers,” 

Hoffman said.

Aaron Ensor believes the windbreak is accomplishing its intended purpose and based on the positive feedback and appreciation he has received from others, he knows his dad made a great 

public relations decision when the trees and shrubs were put in 

the ground back in 2006. These benefits will continue to grow. ]

Above: Darren Hoffman, NRCS, left, Tom Secrease, middle, and Aaron 

Ensor, right, chat near a windbreak on the Z-Base Farms, which is owned 

by Kent Ensor, Aaron’s father. Below: A windbreak works to conceal 

and help disburse odors at the hog confinement buildings on the Z-Base 

Farms in Monroe County, MO. Photos by Nate Goodrich

 Volume 20, Issue 1 ] Inside Agroforestry 7

Out of sight; out of mind?

Nate Goodrich

NRCS

Columbia, MO
8 Inside Agroforestry ] Volume 20, Issue 1

Historically, field windbreaks have been designed to increase crop 

quality and production, to reduce soil 

erosion and to protect and improve human 

habitats. However, while windbreaks are 

typically designed to reduce wind velocity, 

soil erosion or snow drifting, these designs 

also can be embellished to provide bees 

and other pollinators with habitat, food 

resources and protection from pesticide 

drift.

These additions include flowering trees 

and shrubs that provide pollen and/or 

nectar throughout the growing season to 

support bees, our major crop pollinators, 

and a greater use of taller trees and shrubs 

with denser growth to prevent pesticide 

spray drift. 

Besides providing habitat and safety 

for pollinators, the additional agroforestry 

benefits include wood production (maple, 

for example, is an excellent source of early 

spring pollen and hardwood timber) and 

income from fruit, berry and nut crops, as 

well as decorative florals and biofuels.

Windbreaks designed to prevent pesticide drift should emphasize greater use 

of evergreens, trees or shrubs with denser 

growth habits and taller species. 

Both approaches fit within the common types of windbreaks recommended 

by the USDA Natural Resources 

Conservation Service (NRCS): Field 

windbreaks, livestock windbreaks, 

farmstead windbreaks and living snow 

fences (see National Agroforestry Center, 

www.unl.edu/nac/windbreaks.htm for 

detailed criteria for effective windbreaks). 

Windbreaks designed as habitat for 

bees and other pollinators should provide 

a diversity of pollen- and nectar-rich 

flowers through the growing season (Table 

p. 9), that will provide a consistent food 

supply and, over time, support diverse bee 

populations. This is particularly important 

when nearby crops vary from year to year 

(i.e., when crop resources are inconsistent 

from year-to-year) and when floral 

resources in a crop field are abundant 

for only short periods of time, such as 

blueberries and apples.

Windbreaks also help bees conserve 

energy by protecting them from the wind. 

Nancy Adamson

Pollinator Conservation Specialist

Xerces Society/NRCS-ENTSC

Thomas Ward

Forester, NRCS-ENTSC

Mace Vaughan 

Pollinator Program Director

Designed with pollinators in mind

see Pollinators, Page 10

HABITAT ENHANCEMENT

A bumblebee foraging on a blueberry blossom. Photo by Nancy Adamson

A sweat bee gathers pollen on a nine-bark. 

Photo by Mace Vaughan
a

Names in bold include some or all evergreen species.

bFlowering times depend on species, location, and environmental conditions, 

varying from year to year. Consult with local native plant experts to plan for 

overlapping bloom times.

cAdded value as timber. 

dAdded value of fruit crop.

e

Added value of decorative cut twigs for floral industry.

f Southern distribution only.

 gThis species is invasive in some parts of the country and should not be planted 

in those regions.

Scientific Name Common Name Bloom Timeb Height

Short (S), Medium (M), Tall (T)

Region

West (W), Central (C), East (E)

Acer spp.

c maple spring to early summer T WCE

Amelanchier spp.d serviceberry early spring to summer SM WCE

Amorpha spp. leadplant, false indigo spring to summer S WCE

Aralia spp. devil’s walkingstick, 

spikenard

summer SM WCE

Arbutus spp.e madrone early spring to summer MT WC

Baccharis spp. groundsel bush, coyote brush summer to fall S WCE

Ceanothus spp. native lilac, NJ tea early spring to summer SM WCE

Cephalanthus occidentalis buttonbush summer SM WCE

Cercis spp. redbud spring M WCE

Clethra alnifolia sweet pepperbush summer S CE

Crataegus spp. hawthorn spring M WCE

Diospyros spp.c,d persimmon spring T WCE

Gaylussacia spp. d huckleberry early spring S CE

Gleditsia spp.c honey locust spring T WCE

Holodiscus spp. cliff spirea summer S WC

Ilex spp.e holly, inkberry spring SMT WCE

Liriodendron tulipifera c tulip tree spring T CE

Mahonia spp. Oregon grape spring to early summer S WCE

Nyssa spp.c blackgum spring MT CE

Oxydendrum arboreum sourwood summer T E

Parkinsonia spp. palo verde spring M WCE

Philadelphus spp. mock orange spring S WCE

Photinia spp. chokeberry spring to summer S CE

Physocarpus spp. ninebark spring to summer S WCE

Prunus spp.c,d cherry, plum, peach, apricot spring M WCE

Rhododendron spp. rhododendron, azalea early spring SM WCE

Rhus spp. sumac spring to summer M WCE

Robinia pseudoacacia black locust spring T E

Rosa spp.d rose summer S WCE

Rubus spp.d blackberry, raspberry, black 

raspberry

spring to fall S WCE

Salix spp.e willow early spring MT WCE

Sambucus spp.d elderberry spring to summer S WCE

Sassafras albidum sassafras spring MT CE

Shepherdia spp. buffaloberry spring SM WC

Spiraea spp. spirea summer S WCE

Tilia spp.c basswood spring to summer T CE

Umbellularia californica California laurel fall to spring T W

Vaccinium spp.d,e blueberry, huckleberry early spring S WCE

Inside Agroforestry ] Volume 20, Issue 1 9

Blooming dates for pollinator friendly trees and shrubs
When protected from wind, bees conserve energy (like livestock 

and plants), and are more likely to have greater energy to visit 

adjacent crops for longer periods of time. The sheltering effect 

of windbreaks also creates slightly warmer conditions, enough 

to expand the time period bees forage. By supporting diverse bee 

populations throughout the growing season, successful pollination is ensured even when there is a decline in one or more bee 

species.

Since 30 percent of native bees are cavity nesters, including 

woody plants and cane-producing shrubs within windbreaks is an 

important consideration. The bees’ offspring complete their life 

cycle in beetle tunnels and the centers of pithy stems, so leaving dead wood on-site is beneficial, as is increasing young woody 

sprouts of plants such as boxelder, sumac, caneberry and elderberry 

by cutting them back every few years. These practices can greatly 

increase nesting habitat for native bees. 

Trees and shrubs that are especially attractive to bees vary 

regionally and seasonally and should be chosen based on local 

conditions. Several studies have shown that native species 

are more attractive and provide more resources for native and 

honey bees alike. In general, native species are encouraged over 

introduced species. Adding wildflower species to a windbreak 

also greatly benefits pollinators by providing additional forage, 

and native warm season bunch grasses can provide nesting sites 

for bumble bees. Likewise, renovating established windbreaks 

with smaller shrubs can be added as part of a habitat plan (see 

USDA practice standard for Windbreak Renovation #650). 

For more detailed information about pollinator habitat, visit 

www.xerces.org/pollinator-resource-center

Windbreaks designed to support pollinators also are beneficial 

to other insects and wildlife. Though farmers may worry that this 

habitat could harbor pest species, greater numbers of predator 

species, such as spiders, wasps, hover flies and lady beetles, more 

than compensate. In fragmented landscapes, windbreaks can be 

important habitat corridors for a variety of wildlife, including 

game birds, migratory songbirds and insects.

PESTICIDE DRIFT PREVENTION

When designing windbreaks to prevent pesticide drift, trees 

and shrubs known to be exceptionally effective at capturing spray 

drift should be used while staying away from using plants that 

provide forage for bees or other pollinators. Using this design, a 

windbreak can capture the maximum amount of pesticide drift 

with the least harm done to the pollinators.

Research has shown that, because of their three-dimensional 

porosity, vegetative windbreaks are more effective in controlling 

drift than artificial windbreaks made of wood, cloth, or other 

materials. One note of caution: overly dense windbreaks (greater 

than 60 percent), may lead to wall effects, forcing wind up and 

creating eddies on their leeward side that could bring drifting 

material back down to the surface (known as downwash).

The best pesticide drift protection comes from multiple rows 

of vegetation that include small-needled evergreens. These trees 

are two to four times as effective as broadleaf plants in capturing 

spray droplets and provide year-round protection. A porosity of 

40-50 percent in several rows is optimum for capturing spray 

drift, which can be achieved in a windbreak of several rows. Two 

rows of evergreens can provide a 60-percent density (40-percent 

porosity). Spruce, juniper, fir and arborvitae are recommended 

over pines since pines generally are less dense and their growth 

form opens with age. While multiple rows of low porosity 

vegetation are better than a single row of dense vegetation, even a 

single row can substantially reduce drift. 

Shape, structure and width affect droplet capture effectiveness. 

Species without lower vegetation branches or foliage should 

be avoided or supplemented with low-growing species. Wind 

velocity reduction is proportional to windbreak height and 

density. While some crops benefit by being sheltered from wind, 

maturing more quickly, others may not thrive with less light, 

so structural design needs to balance wind reduction goals with 

consideration of shade effects. 

Windbreak design will depend on site conditions and available 

space. Generally, windbreaks are aligned to intercept prevailing 

winds with one to five rows, starting with a shrub row and 

including an evergreen row. For pesticide drift prevention, they 

also may need to be placed on the leeward side of crop fields to 

prevent movement of chemicals off-site. 

Spacing between rows should be 12-20 feet, guided by the 

mature width of plants and maintenance practices (four feet wider 

than equipment used between rows). Where possible, spacing 

should be closest on the windward (shrub row) and leeward 

(evergreen row) sides, and farthest between the innermost rows 

(deciduous or evergreen trees). Designs with a mixture of shrubs, 

trees, and perennials or fewer rows, can be planted a little more 

densely. In drift prevention windbreaks, avoid nectar-producing 

perennials that might attract pollinators. If grasses are used, 

planting density should be very low to prevent competition 

with shrub and tree growth (until the shrubs and trees mature). 

Minimum height at maturity should be one and one half times 

the spray release height (twice the spray height if porosity is 

expected to be less than 40 percent). 

Buffer zones — unsprayed areas around the edge of the crop 

field — are an alternative and complementary drift management 

technique. To protect pollinators, buffer zones can be mowed 

just prior to spray time if pollen or nectar producing plants are 

flowering within them.

While windbreaks for pollinators are designed to intercept 

pesticides, potential susceptibility of plants to herbicide drift 

should be considered where herbicides are regularly used. 

Windbreaks make up only one component of best management 

practices to minimize agro-chemical drift. Timing (avoiding 

active times of pollinators and choosing times with lower wind 

velocities), nozzle adjustments (smaller droplets travel farther and 

are less easily captured by vegetation) and other spray systems/

techniques can reduce potential drift impacts on pollinators and 

their habitats. 

Windbreaks provide a unique opportunity to address 

conservation threats to pollinators and, at the same time, address a 

wide variety of other resource concerns, from crop production and 

reduced soil erosion to wildlife habitat. Therefore, they continue 

to be a flexible and useful tool for conservation on agricultural 

lands and an important component of a sustainable farm. ]

10 Inside Agroforestry ] Volume 20 Issue 1

Pollinators Continued from page 8
Except for a few places, like southern California, it is often 

said that if you don’t like the weather, wait 5 minutes and it 

will change. Farmers and ranchers are continually adapting their 

schedules and practices to account for changes in weather. There 

also is evidence that climate is changing as well as our shorter 

term weather. There is much debate as to the cause of these 

changes and the extent of anticipated climate changes. Depending 

on location, some areas may become drier or wetter or become 

warmer or cooler than previously. A common prediction is that 

local weather will become more varied, with more extreme 

weather events. All of which creates uncertainty for farmers, 

ranchers and land managers in general.

There are many strategies for managing risk, far too many to be 

introduced here, let alone to be thoroughly discussed. So this article will focus on one strategy — you guessed it — windbreaks.

Windbreaks are grouped with a number of conservation practices called “buffers.” Buffers moderate extremes in, and adjacent 

to, the field where they are applied. Windbreaks buffer the wind 

or reduce wind speed at the field scale. This reduction in wind 

speed results in changes in the micro-climate in, near and around 

the windbreak. 

Windbreaks can have positive effects under changing climate 

conditions at the field, landscape and global scale.

At the field scale windbreaks reduce wind speed resulting in 

less crop transpiration, lower water loss from soil, warmer soils 

and reduced crop damage from blowing soil. Windbreaks also 

protect livestock and homes from cold winter winds, resulting in 

lower energy expenditure and costs for both livestock and home 

owners. 

At the landscape scale windbreaks can also be beneficial. In 

the research paper, “Climate change meets habitat fragmentation: 

Linking landscape and biogeographical scale levels in research 

and conservation,” Opdam and Washer write, “All this implies 

a shift in conservation focus from the local level towards the 

regional and international level. Such a vision integrates three 

components:

1. Stabilizing key areas. Ecosystems most vulnerable to the 

combined stress of climate change and fragmentation are developed as a spatial network.

2. Heterogeneity. Increasing the spatial variation of habitat 

quality in large nature areas and landscapes could make local 

populations less vulnerable to weather variability.

3. Permeability of the landscape. By developing bold 

connectivity zones, networks of narrow corridors can create a 

high density of small, semi-natural landscapes.

All of which is to say that windbreaks can serve as corridors 

and refuges for wildlife and plant species to survive and move 

across the landscape as their habitat changes as a result of changing climate.

At the global scale, windbreaks are one small tool in addressing atmospheric CO2 concentrations. In the paper, “Windbreaks 

and Climate Change,” Brandle, et al. (1992b), assessed the 

potential of windbreaks as a means of reducing atmospheric CO2

concentration. They calculated not only the direct sequestration 

of carbon in the growing trees but also estimated the indirect benefits to agricultural production systems due to crop and livestock 

protection and energy savings.

Windbreaks can play a significant role as agricultural producers strive to adapt to changing climates. But only if they are well 

planned, designed and established. Like they always say, “The 

best time to plant a windbreak was 20 years ago. The next best 

time is today.” ]

Richard Straight

Lead Forester 

National Agroforestry Center

Lincoln, NE

A huge cloud of dust looms over Lubbock, TX, during an October 2011 dust storm. Courtesy photo:The Lubbock (TX) Avalanche-Journal

Varied weather creating uncertainty

 Volume 20, Issue 1 ] Inside Agroforestry 11
Mission

The USDA National Agroforestry Center (NAC) 

is a partnership of the Forest Service (Research & 

Development and State & Private Forestry) and the 

Natural Resources Conservation Service. NAC’s 

staff are located at the University of Nebraska, 

Lincoln, NE and in Blacksburg, VA. NAC’s purpose 

is to accelerate the development and application of 

agroforestry technologies to attain more economically, 

environmentally, and socially sustainable land use 

systems by working with a national network of 

partners and cooperators to conduct research, develop 

technologies and tools, establish demonstrations, 

and provide useful information to natural resource 

professionals.

Policy

Opinions expressed in “Inside Agroforestry” are those of the author and do not 

necessarily represent the policy of the USDA Forest Service and the USDA Natural 

Resources Conservation Service. The U.S. Department of Agriculture (USDA) prohibits 

discrimination in all its programs and activities on the basis of race, color, national 

origin, age, disability, and where applicable, sex, marital status, familial status, parental 

status, religion, sexual orientation, genetic information, political beliefs, reprisal, or 

because all or part of an individual’s income is derived from any public assistance. 

(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 USDA’s TARGET Center at 202-720-2600 (voice and 

TDD). To file a complaint of discrimination, write USDA, Director, Office of Civil 

Rights, 1400 Independence Avenue, SW, Washington, DC 20250-9410 or call toll 

free 866-632-9992 (voice). TDD users can contact USDA through local relay or the 

Federal relay at 800-877-8339 (TDD) or 866-377-8642 (relay voice). USDA is an equal 

opportunity provider and employer.

“Inside Agroforestry” is published by the USDA 

 National Agroforestry Center. 

 Phone: 402-437-5178; Fax: 402-437-5712.

•		 Andy Mason, NAC Director (202-205-1694)

•		Michele Schoeneberger, FS Research Lead

 (ext. 4021)

•		Richard Straight, FS Lead Agroforester (ext 4024)

•		Vacant position, NRCS Lead Agroforester

www.unl.edu/nac

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VOLUME 20, ISSUE 1

Upcoming Events

Has Your Address Changed?

If you’ve had a change of address or personnel, we’d like to know. Please fill out a change of address form on our website: 

www.unl.edu/nac/changeofaddress.htm

Jan. 26-27, 2012 

Kansas Natural 

Resources Conference 

Wichita, KS.

“Wetlands: The Jewels of Kansas”

More information at: 

www.kansasnrc.org/

Feb. 23-24, 2012 

Agricultural Outlook Forum 2012 

Arlington, VA.

“Agriculture: Visions of the Future.” 

For more information go to:

www.usda.gov/oce/forum

July 22-25, 2012

The Northern Nut Growers 

Association’s 103rd Annual meeting 

Lexington, KY. 

More information at:

www.nutgrowing.org/

For more upcoming events, visit 

our website calendar:

www.unl.edu/nac/calendar.htm