Healthcare – “The prevention, 

treatment, and management of illness 

and the preservation of mental and physical

well-being through the services offered by the

medical and allied health professions.” —The

American Heritage Dictionary, fourth edition

VOLUME 17 ISSUE TWO

LIKE human health, environmental

health must be preserved, treated, and

managed. Certain precautionary techniques help ensure the health of individual agroforestry practices, like using

native trees and shrubs, and minimizing threats like emerald ash borer. 

By making investments like these, we

receive the greatest benefit from riparian

forest buffers, windbreaks, and silvopasture systems now and in the future.

Healthy agroforestry systems equate to a

more healthful overall landscape, maximum environmental services, and

opportunities for diversified income. 

This issue of Inside Agroforestry

explores several aspects of agroforestry

health and how they might affect you. ]

3

5

8 Concerns about a 

not-so-precious jewel

Agroforestry is not

immune to climate

change

Diagnosing what ails

your agroforestry 

practices
Time for agroforestry triage

NAC Director’s Corner

A commentary on the status of agroforestry by Dr. Greg Ruark, NAC Program Manager

2 Inside Agroforestry | Volume 17 Issue Two

THE health of our nation’s working lands is being

increasingly challenged by pressures like land development, changing climate, wildfires, and invasive pests.

Maintaining healthy forest and agricultural systems is

essential for preventing the diminution of productivity

and avoiding negative social consequences, like soil erosion, water pollution, and loss of biodiversity. A high proportion of the watersheds in this country are an interwoven mosaic of both rural and urban landuse. Landscape

perspectives that take an all-lands approach are needed to

provide comprehensive solutions that optimize ecosystem

services. Otherwise, it is like trying to make a patchwork

quilt without bothering to sew the pieces together—

everything comes unraveled. 

It is time to perform an agroforestry triage to determine

where in the landscape agroforestry technologies can best

be used. For example, shelterbelts can provide corridors

across agricultural lands to connect forest fragments and

increase wildlife benefits, while also protecting soils, crops,

and livestock. Riparian forest buffers on farms and

ranches can protect surface waters from sediments, nutrients, and contaminants, while enhancing aquatic habitats

and sequestering carbon. Farm woodlots can be used to

grow specialty products like ginseng or mushrooms under

a modified forest canopy, thereby encouraging timber

stand improvement practices. Grazing/timber systems

allow farmers to generate an annual income from grazing

livestock under thinned conifer stands, while producing

high quality sawlogs and avoiding problems associated

with animal feeding operations. At the agriculture/community interface trees can be planted to provide social

benefits and a buffer from agricultural activities and harsh

environments. Finally, it is also important to tend to the

health of the agroforestry plantings themselves to insure

that they produce their intended benefits. ]

HAVE you used CanVis image editing software to communicate ideas or design alternatives to landowners or engage the public in

the design and decision-making process? If

so, we want to hear about it.

To submit your story: tell us about the

project, how CanVis image editing software

helped you communicate your design alternatives, and any simulation creations that

you wish to share. 

The deadline for submission is July 18,

Send us your CanVis visual simulation success story

We want to feature it in

Inside Agroforestry

2008. Send material to: USDA NAC, 1945

N. 38th St., Lincoln, NE 68583–0822. Or

send it via email to Nancy Hammond,

nhammond@fs.fed.us.

CanVis image editing software is an

entry-level image-editing program for natural resource professionals. Using the software you can edit a scanned photograph or

image from a digital camera to create

photo-realistic design simulations. It

requires minimal computer skills.

For more information, or to order a kit

visit NAC’s website: www.unl.edu/

nac/simulation/products.htm#canvis
the climate is changing. Now, what do

we do about it?” 

No single solution or individual management approach is appropriate to all,

or even most situations. Management

tools should be mixed and combined to

best match the particular context. The

two primary tools are adaptation and

mitigation. Adaptation strategies are

those approaches taken to adjust, prepare, and accommodate new conditions

that are created by changing climates.

Mitigation strategies include those

actions taken to reduce and reverse the

human influence on the climate system,

primarily through reduction of greenhouse gas emissions and feedbacks.

Inside Agroforestry | Volume 17 Issue Two 3

CURRENTLY, many natural resource

management strategies and practices are

based implicitly or explicitly on assumptions of a historically stable environmental background. Even when successional or disturbance dynamics and spatial heterogeneity are acknowledged; the

assumption is that the backdrop is

static. Incorporating the implications of

climate change, either natural variability

or human-driven, forces the rethinking

of basic management frameworks and

methods. When managing for climate

change, the point is not just to “think

outside the box,” but to recognize that

the box itself is a moving target. This

leads to the question: “OK, we get that

Reframing

strategies

for climate

change

see Climate change on page 5

Invasion by lodgepole pine (Pinus 

contorta) is a common response to

warming 20th-21st century conditions in

Sierra Nevadan meadows. At Tuolumme

Meadows, Yosemite National Park, CA,

climate change and other historic land

uses have interacted to promote 

recurrent colonization episodes of pine

(left). National Park Service managers

counter these effects by periodically

removing pine seedlings and small trees

(below). Photos by Constance Millar

This article is adapted from Climate

Change and Forests of the Future:

Managing in the Face of Uncertainty, by

Dr. Constance Millar, et al. The article

focuses on forest lands, but the principles

are wholly applicable to agroforestry. Dr.

Millar’s article appeared in Mountain

Views, the Newsletter of CIRMOUNT,

the Consortium for Integrated Climate

Research in Western Mountains. March

2008, Vol 3. She works for the USDA

Forest Service, PSW Research Station.

Rather than using the common rule to

target historcic pre-disturbance conditions

and lake level elevation, water balance

and climate models can realign a lake’s

level to current dynamics and anticipated

future climates. Photo by Constance Millar
4 Inside Agroforestry | Volume 17 Issue Two

PLANT diversity can help absorb the

blows of an insect attack, weed invasion, weather extremes, or even market

changes. Diversity can be looked at as a

disturbance buffer.

Since agroforestry practices require

intense management and each component of the system has an influence on

the others it is important to make sure

that each part of the system is functioning well. One way to maintain the

integrity of an agroforestry practice is to

create diversity within the system. 

Diversity can be created and maintained in several ways. The most

obvious are through varying plant selection and management activities. 

Plant materials

Diversity in plant selection includes

such things as using trees, shrubs, and

grasses, not just trees or only trees and

grass. Different species and even different seed sources for each of these can

also create diversity. Many insects and

diseases are host-specific and those that

attack a variety of hosts do not usually

attack all hosts with the same voracity.

Use of a variety of plant species or even

a mixture of seed sources (still adapted

to your site) may interrupt one of the

common vectors that help to spread

insects and diseases. Similarly, different

species and seed sources often vary in

their susceptibility to weather events

and stressful weather patterns such as

wind storms or drought. 

Because market demands and prices

change, sometimes unpredictably, economic risk can be reduced by growing a

variety of products that respond to different market pressures. Examples of

agroforestry crops that respond to different market demands are timber and

forage, woody decorative florals, and

fruits for jellies and jams.

Management activities

Diversity in management activities

includes not only varying cultural,

mechanical, and chemical treatments

but also their timing. Varying the

timing of treatments like prescribed

burning, grazing, and tilling as well as

choice of pesticides reduces the risk of

favoring the same pest or competing

vegetation time and time again, or

allowing a pest to develop a resistance

to management strategies. Undesirable

plants—weeds—can develop resistance

to a pesticide, especially if only one herbicide is used for control. In the same

way haying, or grazing at the same time

of year or at the same height year after

year, can favor a few forage species and

inhibit others. This can lead to a more

homogeneous plant population that

would be more susceptible to insect,

disease, and weather stresses. ]

Richard Straight

F S Lead Agroforester, USDA National

Agroforestry Center, Lincoln, NE

Variety is the spice of agroforestry

] Product

] Plant selection and arrangement

] Harvesting

] Management activity

] Risks associated with homogeneity

] Function of diversity

Diversity can be

created and maintained in several

ways. The most

obvious are

varying plant

selection and management activities.

NAC file photos

Types of diversity
Inside Agroforestry | Volume 17 Issue Two 5

to understand what change will happen

at the scales needed by managers. Many

types of actions can assist species,

ecosystems, or resources to move to new

and adapted conditions and processes. 

4. Realign conditions to current

and future dynamics. 

For systems that have been pushed

(manipulated, disturbed) beyond their

natural variability range, actions that

promote alignment with current conditions and processes may be the best

approaches for restoration rather than

returning to historic conditions. Using

historic range of variability and

returning habitats to pre-settlement or

pre-disturbance conditions are widely

used models for ecosystem restoration,

but are often inappropriate because so

much change has occurred since predisturbance times. Re-aligning or

tuning to current and anticipated environments and processes is more likely

to be successful.

5. Reduce greenhouse gases and

reduce non-renewable energy use.

The forestry sector has an enormous

opportunity to reduce human influences

on the climate system. Reducing greenhouse gases can be achieved through

management actions designed to

enhance sequestration so that carbon

stored in natural resources is retained

longer, emissions are lowered, and nonfossil fuel alternative energy is favored.

By contrast, poor management, a lack

of management, or inadequate management can inadvertently accelerate negative effects. An example is an increasing

number of large catastrophic forest fires.

Today, more than ever, the demands we

face exceed our capacity to mitigate

them. The conflicts among our management choices have higher stakes.

Evaluating options and setting priorities

will be increasingly important. At an

overall level, we have three options for

engaging climate-management, each

defensible under different scenarios. We

can do nothing (no advance planning),

react after disturbance or extreme events

(when trajectories are often adaptively

reset under natural conditions), or we

can act proactively. ]

Management adaptation strategies

can be summarized by the 5 R’s:

1. Increase resistance to change.

High-risk, high-value, and/or extremely

urgent situations, such as critically vulnerable endangered species, extreme

fire-risk situations, or volatile invasive

species epidemics, are the most appropriate subjects for resistance management. In such cases, using great force to

armor resources against change may be

the best option. This action can be

extremely expensive, consume a lot of

time, resources, and staff effort, and

may be only short term. Resisting

change can be risky; in many situations

conditions will eventually become so

different that a resource threshold passes

and resistance becomes futile. 

2. Promote resilience to change.

When a species, habitat, watershed, or

other natural resource returns to its

former condition or function after disturbance, it has “resiled." A widely

held, but mostly untested assumption is

that “healthy” species, forests, or

ecosystems are more resilient to change.

Thus, preventative treatments aimed at

increasing health are prescribed. As in

resistance options, strategies to promote

resilience are likely to be successful only

for the relatively short-term, in that

eventually changed climates will force

new environmental conditions such

that ecological re-setting rather than

resilience will be the “healthiest” path

toward adaptation.

3. Enable ecosystems and

resources to respond to change.

Responding to and managing change is

the most proactive of the 5 R’s

approaches. This strategy assumes that a

decision-maker acknowledges the

inevitability of change and adopts the

humility that we have limited capacity

Climate change

continued from page 3

Biomass production from wood

fiber removed

during forest fuel

reduction treatments provides

alternative energy,

thereby reducing

fossil fuel 

consumption. Photo

by Mark Nechodom, U S

Forest Service

] Assist species and resources to 

follow changing environments. 

] Anticipate and plan for associated 

risks. 

] Experiment creatively and learn 

from experiments. 

] Use redundancy.

] Relax genetic-management 

guidelines.

] Experiment with refugia. 

] Increase diversity.

] Promote connected landscapes.
Assessing land health 

6 Inside Agroforestry | Volume 17 Issue Two

Lyn Townsend

Forester, West National Technology Support Center, Natural Resources

Conservation Service, Portland, OR

AGROFORESTRY systems can be built to achieve landowner objectives and

address resource issues. To do this sustainably, the health of the individual practices,

the system, and the site are paramount. But, what is health?

A healthy agroforestry system is likely “balanced” in terms of providing enough

amenities and products while maintaining or improving environmental conditions at the

site, and having minimum or no negative impacts on the nearby landscape. Further, it is

likely free of debilitating levels of pathogens or pests and gives rise to an acceptable

sense of well-being by the landowner, family, and neighbors.

Numerous quantitative and qualitative tools are available to address site-level

health. Two examples to assess stream and associated riparian settings are:

1) Stream Visual Assessment Protocol – Trained conservationists conduct a qualitative evaluation of a stream-riparian area. Up to 15 components are observed; those

relating to riparian habitat and cover are the components most likely to be modified

using agroforestry practices. The protocol is available at www.nrcs.usda.gov/

technical/ECS/aquatic/svapfnl.pdf.

2) Stream*A*Syst – This assessment system is a set of materials for landowners

who want to learn more about managing streamside areas. The assessment is qualitative, points to sources of professional help, and is available at http://extension.

oregonstate.edu/catalog/html/em/em8761/.

Currently, no assessment techniques specifically evaluate health of agroforestry

systems and the landscape footprint on which they occur. Determining agroforestry

landscape health is complex and may require considerable time and an interdisciplinary team to evaluate site conditions. Here are six items to consider:

Soil

Are the site’s soils eroding excessively from

water or wind sources? Is there only a “twodimensional” use of the soil's productive

capacity?

Indicators: rills, ephemeral gullies, windcreated pedestals, wind-blown sediment in

ditches or along fence lines, no trees or

shrubs (their tall heights utilizing the vertical

“third dimension”).

If an agroforestry system exists: Are the

practices on the site configured inefficiently

and poorly spaced inhibiting the soil’s productive capacity? Are they placed ineffectively to control soil erosion in interspersed

cropped or grazed areas during times of

drought and flood? Do tree and shrub

plantings poorly complement soil management activities on cropland, grazing land,

and forest land?

Air

Are there many dusty days? Are neighbors

noticing odors? Are winds increasing

heating needs of farmstead buildings? Are

snowdrifts blocking roads and access to

buildings? Is wind unabated or funneled

through work areas? Are temperatures too

high or low for livestock? 

Indicators: dust in window wells or on

window sills, declarations of non-attainment

areas (including your farm or ranch) by local

or state air quality authorities, vocal neighbors, high heating bills, snow drifts consistently block roads and buildings in the same

place almost every year, livestock stress from

high or low temperatures or mortality.

If an agroforestry system exists: Have

trees or shrubs lost vigor or died from airborne contaminants or high wind speeds?

Are they poorly placed and not intercepting

and sequestering air-driven pollutants, odor,

soil and dust? Are they too infrequent and

sparse to block or reduce winds to facilitate

work around the farmstead and in fields and

lessen climatic stress on livestock? Is snow

not being intercepted and trapped by the

trees and shrubs?

Water

Are pollutants visible in or linked to streams

on or near the property? 

Indicators: excessive sediment, thick

green scum, unusual odors, trash. Have

shallow or deeper aquifers been identified as

contaminated or at risk? Water well reports,

declarations by local or state authorities

about local aquifers.

If an agroforestry system exists: Have

trees or shrubs died or displayed low vigor

due to water-borne contaminants such as

excessive nutrients or pesticides ? Are they

poorly placed and not intercepting and

sequestering water-delivered surface and subsurface pollutants?

Animals

Are livestock or wildlife being stressed from

inadequate protective cover? Are travel corridors between patches of tree or shrub habitats disconnected? Does wildlife have inadequate seasonal food including woody plant

sources? Are common or desired wildlife

reproducing poorly? 

Indicators: lower than normal numbers

of adults or offspring, unexpected mortality

or behavior.

If an agroforestry system exists: Are tree

and shrub plantings insufficient in amount

and configuration to meet habitat needs? Is
Inside Agroforestry | Volume 17 Issue Two 7

no supplemental income from tree or

shrub products, worker irritability.

If an agroforestry system exists: Are

tree and shrub species ineffective in ameliorating climatic extremes and not producing supplemental income? Are tree

and shrub plantings haphazardly

arranged and detracting from the farm

or ranch’s aesthetic and scenic values?

If there are many “yes” answers,

reconsider the health of the enterprise and the existing use, condition,

and arrangement of trees and shrubs.

Regardless of how questions are

answered, consider a “check up” by

public or private planners who can do

a thorough examination and provide

ideas on how to establish or improve

the effectiveness of an agroforestry

system.

Ultimately, strategically placed

and healthy agroforestry systems can

be a practical and rewarding solution

to improving enterprise diversity, and

income needs or mitigating environmental impacts at the site and on

nearby landscapes. An agroforestry

system is not the only approach but it

does provide a strong complement to

an existing agricultural and grazing

venture. ]

THE forestry community is afire with

discussions and programs related to

forest health. Many of the issues hovering around this issue are relevant to

agroforestry and in fact may be a good

approach to evaluate the functioning and

sustainability of agroforestry practices.

Some of the more mature discussions

of forest health and how they apply to

agroforestry are discussed below. 

In a 1998 American Forests article,

Sampson and DeCoster described forest

health as “a condition of forest ecosystems that sustains their complexity

while providing for human needs.” The

Society of American Foresters suggests a

more lengthy definition: “the perceived

condition of a forest derived from concerns about such factors as its age,

structure, composition, function, vigor,

presence of unusual levels of insects or

disease, and resilience to disturbance”

and it properly recognizes that “perception and interpretation of forest health

are influenced by individual and cultural viewpoints, land management

objectives, spatial and temporal scales,

the relative health of the stands that

comprise the forest, and the appearance

of the forest at a point in time.”

From these two definitions two

aspects of forest health seem to confound the acceptance of a universally

accepted definition: 1) people’s expectations from the forest, such as timber,

wildlife, clean water, and no trace of

human activity, and 2) what scale of the

If you haven’t got

your health, you

haven’t got 

anything

see Health on page 11

Richard Straight

F S Lead Agroforester, USDA National

Agroforestry Center, Lincoln, NE

An interdisciplinary team in Maryland evaluates a stream and riparian corridor 

adjacent to cropland to determine health of this landscape setting. They are using

the Stream Visual Assessment Protocol. Photo courtesy of Lyn Townsend

complementary herbaceous habitat absent?

Are the existing woody species not producing

adequate cover, habitat, and food for

common and desired wildlife? Are plantings

disconnected and not facilitating movement

of wildlife on and through the site?

Plants

Are crop and grazed plants being stressed by

a lack of water or by climatic extremes? Are

fruit-bearing plants unable to produce adequately because of persistent winds or lack of

pollination? Are crops damaged by wind or

crop quality diminished by wind? 

Indicators: lower than normal growth or

production. Fruits and vegetables display

bruises or blemishes.

If an agroforestry system exists: Are

trees or shrubs in poor condition and not

growing as expected for their age and species?

Are the tree and shrub species poorly adapted

to the local climate and soils? Are they

located upwind of crops and forages?

Human

Are costs and revenues not providing sufficient and expected levels of net income?

Does the aesthetic character of the site facilitate a “sense of place” and satisfaction? Are

workers stressed from climatic extremes?

Indicators: declining net revenues, one or

two products are the single-source income,
AN exotic beetle from Asia has four

Great Plains states very concerned. Since

it was first identified in southeast Michigan in

2002, estimates are that the emerald ash borer

(EAB) (Agrilus planipennis Fairmaire)

has already destroyed over 30 million ash

trees. EAB is a threat to all North

American ash trees regardless of age or

condition. The northern plains region

is especially vulnerable since this area

has the highest percentage of ash of any

place in the United States. Most Great Plains

communities have at least 25 percent, some up to

60 percent of their tree resources being green ash

(Fraxinus pennsylvanica). Additionally, estimates

are that over 50 percent of the agroforestry plantings

on the rural landscape have a green ash component.

EAB is present in Michigan, Illinois, Indiana, Ohio,

Pennsylvania, Maryland, West Virginia and Ontario,

Canada. State and federal quarantines are in place and

involve significant survey, containment, and eradication operations in affected areas with limited success. 

Fortunately, EAB has not been identified in the Plains states

yet (Kansas, Nebraska, South Dakota, and North Dakota),

though most scientists consider their arrival inevitable. In a

proactive attempt to raise awareness and become better pre8 Inside Agroforestry | Volume 17 Issue Two

pared, the Great Plains Tree and Forest Invasives

Initiative (GPI) was formed. GPI is

one of three multi-state projects projects that are being funded by the

USDA Forest Service to address one or

more of three national themes:

1. Conserve working forest landscapes; 

2. Protect forests from harm; 

3. Enhance public benefits from trees and

forests. 

The GPI funding will allow the states to

conduct a comprehensive inventory of all

species of trees in rural agroforestry

plantings and in communities to determine areas of the highest composition

of ash which would relate to EAB risk. In

addition, the inventory and assessment will

help the states’ forestry and other natural

resource agencies better plan

and prepare for an arrival of EAB. GPI will also establish a

citizen monitoring program and develop educational material

for the public and natural resource professionals on how to

reduce the rate of spread of EAB and utilization options for

what promises to be a large quantity of ash wood. Perhaps the

greatest value of the GPI is the creation of a transferable protocol for inventorying and preparing for future invasive pest

infestations. For more information, contact Steve Rasmussen,

Great Plains Initiative Coordinator at 402–375–0101 or 

srasmussen2@unl.edu ]

This vial is from a detection kit

that is available through the four

state forestry agencies involved in

the GPI and can be used to mail in a

suspected adult EAB for identification.

Information for creating your own 

detection kit is available from the author.

Photo courtesy of Forestry Images

Steve Rasmussen

Nebraska Forest Service 

District Forester / Great Plains 

Invasive Coordinator, Norfolk, NE

Actual size
Inside Agroforestry | Volume 17 Issue Two 9

HUMANS and fire have had a long

history—sometimes good, sometimes

not so good. According to the National

Interagency Fire Center, over 96,000

fires burned nearly 10 million acres in

2006. This includes wildfires, which

comprised most of the acreage, and prescribed fires. From 1999 to 2006, the

average wildland fire acres burned was

nearly double the average of 1960 to

1998—6.8 million versus 3.5 million

acres, respectively! Why? The most likely

answers are: 1) an increase in fuel loads

on forest and shrub lands resulting from

a lack of active fuel management in

recent decades, and 2) a change in climate or climate cycles. The risk of the

loss of life and property continues to

increase as more and more people move

into the Wildland Urban Interface

(WUI)—pronounced “Wu-eee”—that

fringe of wild land near suburbs or suburbs directly embedded into wildlands.

Fires are classed as either “uncontrolled” or “wild,” or “controlled” or

“prescribed.” Of course, the latter can

become the former with unexpected

high winds or lack of preparation. Fire

relates to agroforestry in two ways: by

using agroforestry practices to control

buffer against wildfire, and by protecting

agroforestry practices from being damaged or killed by fire.

Key practices and how they address

these aspects are:

• Silvopasture – In a silvopasture 

system, trees and shrubs are planted, 

grown, and maintained on a wide 

spacing with an understory that is 

grazed by livestock. Fuel loads are 

kept low, ladder fuels are nearly absent

and, should a crown fire start, the 

trees are spaced widely enough to 

inhibit crown-to-crown spread, 

thereby minimizing the level of 

damage to the trees or to the adjacent

non-grazed forest land. Essentially, a 

silvopasture acts as a “fuel break” 

with grazing livestock providing the 

built-in annual understory fuel 

management.

• Riparian forest buffers, windbreaks,

alley cropping, multi-story 

cropping – These agroforestry 

practices are effective fire control 

techniques when fire-resistant plant 

species, such as many native 

deciduous or succulent-leaf trees, are 

used and the planting is strategically 

located so that it can prevent or at 

least stall the spread of fire from one 

area to another. Prevailing wind 

direction during fire season is an 

important planning criterion for 

locating the agroforestry practice. 

Another tactic is planting fireresistant trees in the outer rows of 

multi-row plantings near homes or on

the edges of small communities. 

Here, the trees create a “three 

dimensional” firebreak and could 

even catch firebrands that typically 

jump ahead and downwind during 

most wildfires. For row-type 

plantings, the outer edge near a road 

(which could be a fire-ignition point) 

can be maintained mechanically as an

effective firebreak reducing the 

likelihood of fires spreading into and 

through the planting. A design 

criterion to consider for selecting trees

and shrubs, particularly shrubs, are 

choosing those species with capability

to resprout after fire. Even though the

damage has been done, at least the 

shrub can regenerate quickly using 

the existing root system.

Wildfires can be devastating, but

defensive agroforestry practices and

strategic design criteria can be crucial

management tools to reduce wildfire

risk and, if fire occurs, minimize the 

damage. ]

Lyn Townsend

Forester, West National Technology

Support Center, Natural Resources

Conservation Service, Portland, OR

Fire... a hot button for agroforestry!

The area or strip

near the road (far

edge of windbreak) will be

maintained 

mechanically as an

effective firebreak

reducing the 

likelihood of fires

spreading into and

through the

planting. Photo 

courtesy of USDA NRCS

Wildfires can be 

devastating, but defensive

agroforestry practices and

strategic design criteria

can be crucial 

management tools to

reduce wildfire risk.
10 Inside Agroforestry | Volume 17 Issue Two

threats to agroforestry health

1

2

3

4

5

6

7

8

9

10

Wildlife can cause significant damage to trees and

shrubs, primarily by feeding on leaves, stems and

twigs, especially in the early establishment stage.

Herbicide drift from nearby agricultural activities can

be a one-time or chronic problem that can reduce productivity and functionality of agroforestry practices.

Competition from weeds and undesirable grasses

can significantly stunt agroforesty growth and

reduce vigor.

Invasive pests such as emerald ash borer and gypsy

moth can be very destructive and even kill valuable

trees in agroforestry practices. 

Seasonal or long-term drought can weaken trees and

shrubs making them susceptible to insect and diseases.

In minutes, a wildfire can destroy agroforestry 

practices that took 20 years to develop and another

20 years to regain the same level of benefits.

Urban development can increase the frequency

and intensity of flooding events, can be a source of

invasive weeds, and even cause the removal of

agroforestry practices.

Uncontrolled livestock can graze, browse or

trample young trees and shrubs, keeping them

from performing their intended benefits.

Economic pressures for short-term investments

and high cash flow demands may lead to removal

of agroforestry practices in order to increase acres

of production.

Climatic factors can cause native insects or diseases

to become a serious problem which creates stress

for trees and shrubs.

THE American landscape has changed dramatically over the

past one hundred years. People continue to claim land and

build homes in the outlying fringe of rural and metropolitan

areas. This demographic shift is increasing the size of the

“rural-urban interface,” where homes and other structures meet

rural agricultural land or natural areas. 

When development takes place we are challenged with managing the negative impacts while still facilitating the benefits.

Strategically located agroforestry plantings can help offset the

negative consequences of development. 

Green infrastructure

Leaving or developing a network of green corridors, like

riparian forest buffers and windbreaks, minimizes disturbance

to natural areas. This helps control soil erosion along stream

banks and roadsides and maintains hydrological flows.

“Ecobelts,” trees and other vegetation strategically located in

the physical space between agriculture and cities, help mitigate

the conflicting lifestyles of urban and country dwellers. 

Wildlife habitat

While some animals are generalists when it comes to food and

habitat others are highly specialized and may be restricted to

feeding on several or a single native plant species or require the

freedom to move across the landscape. The trees, shrubs, and

other plants in agroforestry plantings can help mitigate the loss

of wildlife habitat.

Biodiversity

Residential development displaces native plant and animal

species and degrades unique and diverse biological resources.

Agroforestry practices can mimic natural ecological processes

like plant community succession. Incorporating native species

into agroforestry facilitates native plant-animal associations

such as pollination, seed dispersal, and food. 

Public safety

The increasing number of widely dispersed homes and structures

creates problems for access of emergency vehicles. Agroforestry

practices like living snowfences can help keep roadways open for

emergency vehicles and reduce blowing dust and snow. ]

Kimberly Stuhr

Technology Transfer Specialist / Inside Agroforestry

Editor, USDA National Agroforestry Center, Lincoln, NE

Agroforestry and the

rural-urban interface
Inside Agroforestry | Volume 17 Issue Two 11

forest is under discussion (plantation,

county, state, or ecotype). For the purposes of agroforestry health discussions,

we are most likely concerned with the

site scale and expectations are generally

limited to a discussion of landowner

objectives for establishing the agroforestry practice or system.

Sometimes it helps to understand an

issue by looking at what it is not. In

other words, what does an unhealthy

forest look like? E.L. Barnard, Forest

Pathologist with the Florida Division of

Forestry says: “In fact, more often than

not, catastrophic wildfires and southern

pine beetle outbreaks are simply fevers

and sweats, symptoms of unhealthy

forests, not the cause of same. To the

extent that unhealthy forests and forest

conditions remain, and to the extent that

we focus on treating symptoms (e.g.,

killing beetles, putting out fires) while

neglecting the underlying cause(s) of the

problems (i.e., unhealthy forest conditions), we can expect more damaging

wildfires and more pest outbreaks.” 

So, if we can determine what conditions prevent insect, disease, or fire

related problems, we are well on the way

to defining a healthy forest.

Taking these concepts into consideration when planning and designing agroforestry practices should lead us to applications that both meet the landowner’s

objectives and are resistant to disturbances that would reduce benefits. ]

Health

continued from page 7

A SIMPLE field windbreak planning

scenario that keeps agroforestry health

in mind might look something like this:

A landowner is interested in

reducing soil wind erosion, increasing

wildlife habitat for hunting, and perhaps creating a small business opportunity for his children so that they can

learn the value of money, a day’s work,

and responsibility. 

The crop field is currently under a

conservation plan that utilizes crop

residue as a key tool in controlling soil

wind erosion, however the landowner

recognizes that unpredictable weather

and dry years may reduce crop residues,

allowing soil to blow. 

A system of one- or two-row windbreaks will be designed to reduce wind

erosion even when crop residue is

missing. For the most part, native trees

and shrubs that are adapted to the site

will be used to encourage healthy plants

that are more resilient to stresses out in

the open field. 

The state forestry agency and extension service have been informing the

Field windbreak planning: an example

public that, should it enter the state,

emerald ash borer is a potential threat.

Consequently, native ash trees will not

be used; instead honeylocust, hackberry, and bur oak will be planted,

along with Rocky Mountain juniper

and Norway spruce. The diverse selection of species will help ensure that no

one disease or insect will threaten the

entire windbreak system. 

To accommodate hunting and the

small business objectives, an additional

row of fruit bearing native shrubs, like

American plum and chokecherry, will

be added to two of the broadleaf tree

windbreaks. These shrubs will provide

cover for migratory songbirds, food for

nesting songbirds, and a source of fruit

for the children to harvest for making

jam or jelly. At least one of the windbreaks with the shrubs will be near the

farmstead windbreak to make it easier

to access the fruit harvest and to serve

as a wildlife travel corridor between the

farmstead and the nearby slough. ]

Placement of this

Iowa windbreak

protects the 

farmstead from

troublesome winds

and traps snow.

The habitat it 

provides is 

connected to the

riparian area on

the left (off of the

photo). Photo courtesy

of USDA NRCS

More often than not,

catastrophic wildfires and

southern pine beetle 

outbreaks are simply fevers

and sweats,symptoms of

unhealthy forests,not the

cause of same.” E.L.

Barnard, forest pathologist

“
USDA National Agroforestry Center

East Campus–UNL

Lincoln, NE 68583–0822

PRSRT STD

POSTAGE & FEES PAID

USDA — FS

PERMIT NO G-40

July 26–30, 2008

Soil & Water Conservation Society 

Annual Conference. Tuscon, AZ. For 

more information: www.swcs.org/en/

conferences/2008_annual_

conference/

August 18–22, 2008

Short Rotation Crops International 

Conference: “Biofuels, Bioenergy, and 

Bioproducts from Sustainable 

Agriculture and Forest Crops.” 

Bloomington, MN. For more 

information: www.cinram.umn.edu/

srwc/index.html

September 9–11, 2008

Great Plains Riparian Forest 

Management Summit. Sioux Falls, SD.

For more information: www.unl.edu/

nac/Riparian_Summit.htm

Official Business

Penalty for Private Use, $300

Address Service Requested

InsideAgroforestry VOLUME 17 ISSUE TWO

Upcoming Events

“Inside Agroforestry” is published three times per year by the

USDA National Agroforestry Center. Phone: 402–437–

5178; Fax: 402–437–5712.

• Greg Ruark, NAC Program Manager (256–372–4540)

• Michele Schoeneberger, FS Research Lead (ext. 4021)

• Richard Straight, FS Lead Agroforester (ext. 4024)

• Bruce Wight, NRCS Lead Agroforester (ext. 4036)

• Kimberly Stuhr, Technology Transfer Specialist/

“Inside Agroforestry” Editor (ext. 4013)

• Ryan Dee, Technology Transfer Assistant/

“Inside Agroforestry” Designer (ext. 4014)

www.unl.edu/nac

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. It is

administered by the Forest Service, Southern Research Station; and

its program manager and headquarters are located in Huntsville, AL,

on the campus of Alabama A&M University, while NAC’s staff are

located at the University of Nebraska, Lincoln, NE; University of

Idaho, Moscow, ID; 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. To accomplish its mission, NAC interacts

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

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.

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.

For more upcoming events, visit our 

website calendar: www.unl.edu/nac/

calendar.htm.