remains profit and natural resource management, not carbon storage. Even so, financial credit for storing or “sequestering” carbon

in soils, grasses, trees, and shrubs may become an important factor in helping landowners achieve both economic

and conservation goals.

N a t i o n a l A g r o f o r e s t r y C e n t e rAgroforestry

Fall/Winter 

2000/2001

6-7

see CARBON on page 9

Working Trees: 

Windbreaks for Carbon in the U.S.

James R. Brandle, Professor, 

School of Natural Resources, 

University of Nebraska-Lincoln

Greg Ruark, NAC Director

Inside 

Farmers use windbreaks to accomplish a multitude of objectives. Among

these are the reduction of crop water

stress to improve yield and quality, reduction of soil erosion, snow management,

livestock protection, odor control, wildlife

habitat provisions, and energy conservation around farmsteads.

If society is looking for places to

store carbon, windbreaks are an obvious

choice. Since a large number of landowners already appreciate the value of a

windbreak for the many benefits listed

above, many are interested in discussing

ways to get financial assistance for planting and maintaining a windbreak that was

also designed to optimize carbon storage.

The simple fact that many landowners are

motivated to establish windbreaks for

their own purposes, suggests that these

plantings would remain in place for a

long time. Due to the extensive agricultural land base, especially in the North

Central U.S., large amounts of carbon can

be stored by integrating more windbreak

plantings into the agricultural landscape. 

Trees, shrubs, grasses, and

soil serve as carbon sinks,

storing atmospheric CO2. In

addition to conservation

benefits, agroforestry practices help increase the

global carbon sink capacity, curbing the overflow of

excess emissions.

8

THE CARBON DEBATE:

A PRIMER

... Including

The Carbon Sink

Daily newspapers, professional journals, and the popular press regularly 

carry articles about global climate 

change, global warming, greenhouse gasses (GHGs), CO2 emissions, carbon sequestration, 

carbon credits and the Kyoto 

Protocol. Some people question if these issues are substantive or just environmental hype. Either way, what 

is the role of one natural 

resource professional or 

landowner in this global 

debate? Well, we hope that this issue of Inside Agroforestry helps

to explain some of the components making up the carbon debate

and where they’re headed.

As the Carbon Story unfolds it is important to remember that

the primary focus of producers and resource professionals

“FARM” 

YOUR

PIVOT

CORNERS, TOO!

3

A CONVERSATION

BETWEEN

LANDOWNERS

& NATURAL

RESOURCE

PROFESSIONAL

ABOUT CARBON
Agroforestry and the Carbon Cycle

NAC Director’s Corner

A commentary on the status of agroforestry by Center Director, Dr. Greg Ruark

I

nternational concerns over the increasing atmospheric carbon dioxide level and its potential effects on climate has

grown dramatically in recent years. The discussions are

complex and for some aspects contentious. Numerous bills are

being drafted in the U.S. Congress that raise options for payment to farmers for carbon related activities

(www.thomas.loc.gov). In America some private sector utilities companies are already actively purchasing carbon in the

agriculture and forestry sectors (www.carboncenter.net). This

issue of Inside Agroforestry focuses on the carbon debate and

its relationship to agroforestry.

Carbon based energy sources like coal, gas, and oil all

originated from the conversion of sunlight energy by plants.

A dominant consideration for rebalancing the global carbon

cycle is to find ways to promote the increased growth of trees

and shrubs. Since agricultural activities occur on approximately half of the land in the contiguous U.S., much of the

opportunity to sequester carbon can occur through agroforestry opportunities on farms and ranches. 

Windbreaks – Windbreaks store carbon while also protecting

farmsteads, livestock, roads, people, soils, and crops. Field

windbreaks reduce evaporation and plant transpiration rates

such that per field crop yields have been shown to increase for

most crops from five to 50 percent, even though a portion of

the field has been planted to trees. Research has documented

optimal tree planting levels to be from three to six percent of

the cropped field area. Additional CO2 reductions can occur

from: lower heating costs for farmsteads, lower cost of snow

removal, reduced need for crop fertilizer, lower winter feeding demands of livestock, and improved water use efficiency

Riparian Forest Buffers – Trees grow rapidly, storing carbon,

in riparian zones due to favorable moisture and nutrient conditions. When suitable trees and shrubs grow in these moist

environments they can filter out excess nutrients, pesticides,

animal wastes, and sediments coming from adjacent agricultural or urban activities. 

Silvopasture – Timber/grazing systems managed on the same

area of land have been shown to be practical and economically profitable. In areas like the Southeastern U.S., loblolly pine

silvopasture systems produce significantly more carbon

above- and below-ground when both the tree and grass components are properly managed, than does land managed solely

as a pasture or forest. 

Short Rotation Woody Crops (SRWC) - Low prices for traditional crops have increased the interest of farmers in fastgrowing woody crops, like hybrid poplar and willow trees, for

fuel and fiber. These SRWC systems provide a way of

increasing on-farm income, while also being designed to treat

agricultural, livestock, community, and industrial wastes. The

rapid growth of SRWC results in high rates of nutrient uptake

and large amounts of carbon storage over rotation lengths as

short as five to 15 years. Net carbon benefits are realized if

the wood fiber is used for solid wood products or biofuel.

2 Inside Agroforestry | Fall/Winter 2000/2001

www.unl.edu/nac

new look: with MACROMEDIA FLASH

new content: timely topics, site map

new publications: carbon brochure, 

AFTA and RC&D reports

A new Center for Subtropical Agroforestry has been created to take on research, extension, education and training

activities focused on biophysical, environmental, and economic aspects of agroforestry. The new Center is located at the

University of Florida-Gainesville and is led by Dr. P.K. Nair.

Several other investigators and collaborators from Universities

in the Southeast and the Virgin Islands are partners. The

Center will draw upon an advisory committee consisting of

representatives from NAC, academic, government, and nongovernmental agencies. Landowners will help monitor and

evaluate projects.

NEW Center for 

Subtropical Agroforestry
plants to blame? What

can we do to make a difference? 

Rich: Well, they are

major contributors, but you and I produce

CO2 emissions just by driving our vehicles

and heating our homes. Everyone needs to

try and reduce the amount of greenhouse gas

they produce. This can be accomplished by

burning cleaner fuel and reducing the

amount of driving that we do.

Another way you can make a difference is

to store carbon so it doesn’t get into the

atmosphere. Over the years farmers have

tilled the soil and cleared permanent vegetation. These practices release large amounts

of carbon into the atmosphere. Storing carbon in the soil as organic matter and in permanent vegetation helps limit the amount of

CO2 in the atmosphere. 

Wayne: Well, Rich, you know as well as I

do that in order to produce a crop we need

to till the soil and burn fuel.

Rich: That’s right Wayne. But you can

store carbon by increasing the organic matter in the soil by switching to farming methods like reduced tillage. Rotating crops and

incorporating small grains, and applying

amendments, like compost and manure, can

also increase the amount of carbon in the

soil. All of these can help, but the biggest

Fall/Winter 2000/2001 | Inside Agroforestry 3

Editors Note: Numerous utility companies have begun to buy carbon offset credits

to make up for their CO2 emissions. This is

a fictitious conversation depicting one of

several possible scenerios on how carbon

credits may come to be bought and sold. It

could take place in Any-Small-Town,

America. Imagine Wayne and Art, two

landowners, gathering in the café for a

morning cup of coffee. In walks Rich, a

local Resource Conservation &

Development (RC&D) Council Member...

Art and Wayne: Hey Rich. How’s winter

been treatin’ you?

Rich: Pretty good. As soon as the weather

breaks I’ll be out in the field again.

Art: I’ve been busy feeding livestock and

getting my records together for tax season.

Wayne: Hey, I’m glad we ran into you.

What is all this talk about carbon that we

keep hearing so much about? 

Rich: Carbon, well actually carbon dioxide (CO2) is one of the gases that is contributing to the greenhouse effect that is

changing our climate.

Art: Well, aren’t factories and power

gains can be made by planting permanent

vegetation. 

Wayne: That sounds good, but I don’t

want to take more land out of production for

the good of the environment. I’ve already

done my part.

Rich: Not all of your land is prime farmland. Some of your marginal land would be

better off covered with permanent vegetation to reduce erosion. There are numerous

agroforestry practices you could use.

Windbreaks reduce evaporation and water

stress on crops so much that the increased

production in adjacent fields often offsets

the loss of land to trees and can potentially

provide wood products. Riparian buffer

strips can help improve water quality in your

pond. Some of your drainage ways would be

better off in grass to keep those gullies from

forming and reducing those repairs you have

to make every time you hit them with your

farm equipment. 

You may also be able to get paid for storing carbon. While there are currently no

requirements for companies to reduce CO2

emissions, some companies are looking at

their alternatives. And, one alternative is to

“purchase” carbon emission reduction credits (CERC) from people like you. 

Wayne: So, big companies may want to

buy carbon that is stored on my farm? Now

we’re talking! How can I start “growing”

carbon? 

Rich: Companies are already identifying

and developing procedures for various management activities and methods that might

qualify for CERC’s.

If this system comes into being, it looks

Tim King, Director of Carbon Technology

Transfer Center

Janet Kidder, Pacific Rim RC&D Assistant

A Conversation

About Carbon Credits

see CONVERSATION on page 10

With all of this talk about carbon, a key challenge has been to reduce duplication of effort and streamline procedures of operations for carbon producers,

sellers, administrators, marketers, brokers, and buyers. The newly formed

National Carbon Technology Transfer Center is located in Spokane, WA and its

goal is to coordinate this effort. Visit their web site to see how partners from

across the nation and internationally are working to achieve this goal. The site

also contains a wealth of information on many carbon topics including: growing

carbon, carbon sequestration, the carbon cycle, and the carbon offset program. 

www.carboncenter.net
WILLOW

4 Inside Agroforestry | Fall/Winter 2000/2001

A Renewable

Energy Source

Is Growing On

Western New

York Farms

Article adapted from “A New Renewable

Energy Source Growing On Western New

York Farms” by Stacie Edick and Tim Volk.

The New York Forest Owner Volume 37:

Number 5, September/October, 1999. pp 6-8.

Carefully selected hybrid willow bioenergy crops help supply fuel that can be co-fired

with coal in electric power plants. Renewable energy resources, like willow and poplar

can help ease concern about global warming and air pollution, provide rural economic

development opportunities by designing alternative uses for farmland, and reduce the need to

depend on imported energy.

Market

Bioenergy crops are attractive to the power generation industry because they can help reduce

emissions at the power plant. Co-firing wood with coal reduces sulfur emissions, and under certain

conditions can also reduce nitrous oxide emissions. Willow biomass crops are considered carbon

dioxide neutral because the growing crops absorb as much CO2 as is released during production and

burning of the fuel. This aspect will become increasingly important with the increasing concern over

global warming and the need to constrain levels of atmospheric carbon.

Why Willow?

Many people perceive that willow is not a good choice for firewood and question why it would

be grown for fuel. While willow does not compare well on a volume or per cord basis to other woods

such as maple and beech, it does in fact provide as much energy or BTU’s on a weight basis. So,

although it is not a good choice for a wood stove (which would require frequent loading), it is an

excellent choice as a fuel crop for power plants. 

Willow trees have been selected for their ease of establishment, rapid growth, strong coppicing

ability (the stumps resprout when cut), and disease resistance. Once established, willows fully occupy

the site and are a low maintenance crop compared to annual crops. Coppice harvesting every three

years allows multiple harvests from the same rootstock, so fields do not have to be replanted for 21

years or seven harvests. Willow crops produce five to seven oven-dry tons per acre per year, or 15 to

21 oven-dry tons per acre at harvest. These advantages make willow a promising bioenergy crop.

Willow Biomass as an Energy Source

Willow biomass is a clean, versatile wood energy source with potential as a fuel for generating

electricity. It can be burned directly, co-fired with coal, gasified for use in gas turbines, or converted

into liquid fuels. For every unit of energy invested in the production and conversion of willow biomass to electricity, 20 to 30 units of energy are produced. Willow’s ability to effectively capture and

convert sunlight to biomass is a major factor in this positive energy balance. The balance could double over the next decade as yields increase and the production system is optimized.

Production System

Willow biomass plantations in New York are adapted from a commercial system used in

Sweden, where there are more than 35,000 acres of willow energy plantations. The system is based

on double-row plantings of approximately 6,200 trees per acre. Trees are cut after the first year to

promote sprouting. Harvesting then occurs every three to four years in the winter after leaves fall

from the trees. Modified corn or sugar cane harvesters, or specially designed machines that cut and

chip the willows in one process, are used to harvest the crop. Plants resprout following each harvest,

which makes willow biomass crops perennial with a life span of about 20 years, or six to seven rotations.

Other Benefits

Willow crops can also provide multiple non-market benefits. Cornell University’s Department

of Ornithology is conducting studies on bird diversity in willow crops. Thirty-four bird species have

been seen and seven of these have been found nesting in the willow plantings. Harvesting occurs in

the winter months when birds are not nesting. Furthermore, willows attract successional species,

birds that choose habitats of fields changing into forest. These birds are accustomed to finding new

nesting sites every few years or even every season.

To Find Out More

Visit SUNY College of Environmental Science and Forestry’s Willow Biomass web site:

www.esf.edu/willow. For more information on the Willow Bioenergy Project, contact Stacie

Edick, Biomass Field Representative, stedick@nynorwich.fsc.usda.gov.

Three-year-old willow on

seven-year-old rootstacks.

Photo courtesy of SUNY-ESF.
Fall/Winter 2000/2001 | Inside Agroforestry 5

I

t's not true anymore! When you hear

the words "hybrid poplar" they no

longer refer to those tall, skinny

Lombardy poplars that were once planted

for visual screens. No, now days, hybrid

poplar usually means cottonwood or

aspen. They are the fastest growing, temperate-region, tree species in the world.

And, because of their high nutrient uptake

ability, poplar plantations are currently

being used to treat municipal, industrial,

and livestock waste, landfill leachate, and

stormwater runoff. All this while being

used to store carbon too! Much of the

technology is still in its infancy, but that

is quickly changing. More information on

the benefits of poplars and their many

uses follows. 

Poplar Growth

On good sites, hybrid poplar can rival the

growth of many tropical tree species. In

the Pacific Northwest on deep alluvial

soils with ample ground water, hybrid

poplars have exhibited height growth of

15 feet-per-year with annual diameter

growth averaging 1.5 inches. It is not

uncommon for 10-year-old trees on average sites to reach heights of 70 feet and

diameters of 12 inches. It is because of

these growth rates that hybrid poplars

were first used for energy plantations and

chip production for paper manufacturing.

In the last three years, testing of hybrid

poplars has shown that they can also be

used for veneer and solid wood products.

This information has led some companies

and landowners to establish poplar plantations. When grown for these high value

products, poplars are usually planted at

wide spacing (e.g. 14 feet by 14 feet) and

managed with a pruning regime that produces a 20 foot, knot-free log. The economic return from these veneer quality

logs can provide substantial income for

farmers and landowners even from woodlots of less than 40 acres.

Poplar Breeding

The wide-spread, coordinated breeding

efforts by universities, government agencies, and private timber products companies over the past two decades have led to

the economic success of hybrid poplar

management. Organizations involved in

Jon D. Johnson

Associate Professor, Intensive Forestry,

Washington State University: Puyallup, WA

Emerging Hybrid Poplar Technologies

hybrid poplar breeding research include

the universities of Washington State,

Iowa State, and Minnesota, the U.S.

Forest Service Institute of Forest Genetics

in Rhinelander, Wisconsin, The

Department of Energy’s Oak Ridge

National Lab, and forest products companies like Fort James, WESTVACO, and

Boise Cascade.

Poplars and Wastewater

In the last three years traditional forestry

use of hybrid poplar has been expanded

to designs that provide environmental

benefits. Most recently poplar plantations

have been used to treat wastewater from

dairies, other animal feeding operations,

municipal sewage, landfill leachates, and

industrial processing. Rapidly growing

poplars take up large amounts of water,

nitrogen, phosphorus, and other nutrients.

The extensive fine root system provides

an ideal filtering mechanism for wastewater. Applying wastewater to hybrid

poplars can cost significantly less than

conventional engineering treatment methods. The costs are even lower when the

trees are later harvested and sold.

Wastewater treatment solutions using

hybrid poplars are environmentally sound

solutions that can improve public relations while also enhancing aesthetics and

reducing odor. 

Poplars and Carbon

Poplar plantations are starting to receive

attention as a method to absorb and store

carbon (referred to as carbon sequestration). While all green plants are capable

of sequestering carbon through photosynsee POPLAR on page 11

Northern West Plains Midwest Northeast Southeast

Looks promising, but too

early for recommednation

Poplar species 

suitable

P. trichocarpa

(black cottonwood)

P. deltoides 

(eastern cottonwood)

P. trichocarpa

(black cottonwood) X

P. deltoides

(eastern cottonwood)

P. deltoides

(eastern cottonwood) X

P. nigra

(European black poplar)

P. nigra 

(European black poplar)X

P. maxmowiczii

(Oriental species )

P. deltoides

(eastern cottonwood) X 

P. maximowiczii

(Oriental species)

Common

Populus Species

Common Parents and Hybrids

Being Tested and Developed and

Their Geographic Suitability.

?

?
6 Inside Agroforestry | Fall/Winter 2000/2001

The United Nations

Framework Convention

on Climate Change

(UNFCCC)

1997

1992

1990

2000

Carbon dioxide (CO2) in the atmosphere helps keep the earth

warm by trapping the sun’s energy and slowing its escape

back into space. This heat trapping ability is called the “greenhouse effect”, and it is necessary to prevent the earth from becoming inhospitably cold. Although the largest concern is over CO2, several gases are known to trap heat. In the past 150 years since the

beginning of the industrial age, the level of atmospheric CO2 has

risen at an alarming rate. Carbon dioxide is produced whenever fossil fuels, such as coal or oil, are burned in power stations or gasoline

is consumed in cars. America, with four percent of the world’s population, accounts for a quarter of the world’s total emissions. Since

1850, concentrations of CO2 have increased from 285 to 366 parts

per million, or nearly 30 percent. 

There is scientific consensus that the high CO2 level is beginning to trap more heat. Historical records constructed from ice

cores, tree rings, and fossils document that the average global temperature has risen more in the last century than at any time in the

past 10,000 years. Although there is little dispute that an increase in

global temperature will alter climate, the specific impacts are greatly debated. Some regions could be affected more than others and

many scientists feel that the occurrence of extreme weather events 

1997

2000

In their escalating efforts to prompt international action on climate change,

the COP met in Japan in 1997 and created the Kyoto Protocol. It calls for industrialized nations to meet targets for reducing greenhouse gas emissions by at

least five percent from their 1990 levels for the first accounting period of 2008-

2012. The U.S. commitment under the Protocol calls for a seven percent reduction in emissions. Developing countries are exempted from targets for now. To

help meet its mandated target an industrialized country could employ the socalled “Clean Development Mechanism”, which allows them to produce financial credits to developing countries to invest in emission reduction projects.

Although the U.S. has signed the Protocol, the Senate has not ratified it.

The Protocol recognizes that reducing the rate of atmospheric CO2 level

increases can be achieved by both the reduction of activities that consume fossil

fuels and by activities that result in the planting of vegetation. Within the Kyoto

Protocol there are two primary articles related to forestry and agriculture. They

are:

Article 3.3 – refers to direct human-induced land use change and forestry activities, limited to afforestation, reforestation, and deforestation since 1990.

Article 3.4 – refers very generally to human-induced activities and could be interpreted to

embrace all other carbon activities related to forest, agriculture, and rangeland. This

could include sustainable forest management, storage in forest products, wood recycling,

farm tillage methods, and grazing practices. 

The most contentious debate is over Article 3.4. The U.S. would like to

see mitigation practice, such as increased soil carbon and reduced tillage, included. The U.S is also arguing to have other forestry benefits included, like getting

credit for forest management. Countries with large populations relative to their

forest and agriculture land base, such as the European Union, see very limited

opportunities for activities on farms or in forests, as compared with countries

Kyoto Protocol

the

In 1992, at what has been termed the

“Earth Summit” in Rio de Janeiro, Brazil,

the U.S signed onto the United Nations

Framework Convention on Climate

Change (UNFCCC) along with about

170 other nations. The U.S Senate later

ratified the UNFCCC, thereby giving it

treaty status and making it a legal commitment under U.S. law. However this

Convention merely called for non-binding actions. The UNFCCC has both

political and science components.

Conference of Parties (COP)- This is the

policy and decision-making body of the

UNFCCC. Initially the COP approach was to

call upon nations for non-binding actions and

general goals. However, this approach has

proven to be inefficient. As the science underlying global climate change has become more

definitive, the COP has moved to negotiate

legally binding commitments of specific

reduction targets and timetables for each

nation.

Intergovernmental Panel on Climate

Change (IPCC) – This is the science advisory body of the United Nations and it provides

technical support to the COP. It was established in 1988 by the United Nations and the

World Meteorological Society. It is comprised

of over 3000 scientists from around the world

and conducts assessments of the current state

of scientific, technical, and economic knowledge on climate change, its causes, impacts,

and mitigation strategies.

1990

1992
by Greg Ruark

like hurricanes, floods, and droughts could become more frequent

and intense.

There are two ways to manage atmospheric CO2 concentrations, and both approaches will need to be used extensively to deal

with this issue. One way is to reduce the amount of fossil fuel that is

used and the other is to increase activities that absorb CO2.

However, even with widespread adoption of both approaches the

global concentration of CO2 will still continue to rise, but will do so at

a lesser rate. There is considerable debate revolving around the role

of agriculture and forestry in helping to absorb atmospheric CO2.

Technically, both can increase the long-term storage or “sequestering” of carbon through changes in management practices, like

reduced tillage that can increase soil carbon levels and the planting

of long-lived vegetation like trees and shrubs. 

The debate on the carbon cycle has taken on international

importance and has the potential to affect not only the environment,

but the economies of nations. To understand the origins of this

debate and its potential impacts on agriculture and forestry in the

U.S., it is useful to understand the formal organizational structure

that has been established internationally to structure the debate,

establish policy, and set specific reduction targets and timetables. 

Special Report on Land Use,

Land-Use Changes and

Forestry (SR-LULUCF)

This report was released by the IPCC in June

2000 to assist nations in developing agreements and

action programs to address climate change. The

report examines the scientific and technical understanding of the global carbon cycle in relation to land

usage, agricultural and forestry activities. The report

can be downloaded at www.ipcc.ch/pub/reports.

Over the last 150 years of land use changes, primarily from the conversion of forests to other land

uses, have contributed about one-third of the total carbon emissions to the atmosphere, as compared with

two-thirds from the burning of fossil fuels and the production of cement. However, during the last two

decades terrestrial systems have stabilized and

become net carbon “sinks”, with losses in carbon due

to land use, land use change, and forestry practices in

the tropics being more than offset by carbon gains

from these activities in temperate and boreal systems. 

A basic conclusion of the report is that agriculture and forestry activities provide an opportunity to

increase the uptake of carbon from the atmosphere

into the terrestrial biosphere through afforestation,

reforestation and improved forest, cropland, and

range-land management activities. However, a consistent set of definitions and accounting procedures,

coupled with a measuring and monitoring system, are

needed to allow governments to accurately reflect the

exchanges of carbon between the terrestrial

biosphere and the atmosphere.

2000

1990

like the U.S., Russia, and Canada. A “full carbon accounting” system would allow credit for forests that are relatively young and growing significantly in terms of both wood volume and carbon. 

Due to the unprecedented economic growth during the last

decade, U.S. emissions from the use of fossil fuels are currently about

16 percent higher than they were in 1990 and are projected to be 30

percent above 1990 levels by 2010. If the Senate were to ratify the

Protocol, it would attain treaty status and become a legal commitment

under the laws of our nation. As currently written, the Kyoto Protocol

does not include targets for large developing countries like China,

India, and Mexico, even though they have expanding economies and

may soon become the leading emitters of carbon, as well as major

competitors in world markets.

Bottom line: The Kyoto Protocol currently allows carbon credit for

afforestation and reforestation (planting or replanting of trees and

shrubs) that has occurred since 1990 or will occur in the future. Still

under debate is whether to allow credit for carbon absorbed due to

forest management. Agricultural practices that increase soil carbon

levels, like reduced tillage, are also not presently allowed, but are

being vigorously argued for inclusion by the U.S. and others. In the

final analysis, agriculture and forestry are simply so important to the

global carbon cycle, and offer many cost effective ways to offset

emissions from the continued use of fossil fuels that it is almost

inevitable that they will be part of the solution. The Kyoto Protocol is

unlikely to be enacted internationally without U.S. participation. The

protocol is “a work in progress.” Many provisions remain to be

worked out before it would likely be considered by the U.S. Senate

for ratification.

:a primer

1997

1990

1992

Fall/Winter 2000/2001 | Inside Agroforestry 7
Gary Kuhn 

NAC Agroforester

David and Ted Melgren of Othello, Washington between a 10-inch-diameter, five-year-old poplar planting in one of their pivot corners.

8 Inside Agroforestry | Fall/Winter 2000/2001

need for weed control so the Melgrens recently planted ponderosa

pine in the understory to further enhance wind protection, aesthetics and wildlife habitat. Because of the tree pruning and wider

spacing, there is plenty of sunlight for the pine. The Melgrens’

plan is that once the poplars are cut at age 10, the pines will be

well established in the corners for aesthetics and wildlife.

Since Othello usually receives only about eight inches of precipitation per year there aren’t many trees around. Melgrens’ trees

not only produce a viable economic product they also provide

some wind protection to the crop in the pivot. Additional benefits

of the poplars are that they add an aesthetic quality to the landscape and produce wildlife habitat.

“You have to really want the trees and be able to devote time

to care and management,” commented David. They initially struggled with weed control, supplying adequate water, and girdling

damage from voles. But, as they say, hindsight is 20/20. And

while it is true that Ted and David could have benefited from

technical information on poplar culture and management earlier in

their establishment efforts, their first-hand experience will prove

valuable to future irrigated poplar production, especially in 

the Northwest region.

“Farm” Fast-Growing Poplars

and Produce a Product

Don’t Leave Pivot Corners “Empty”

So what do you do with that little bit of land that is left on

the corners of irrigated circle pivots anyway? “Why not

plant trees?” ask Ted and David Melgren, farmers from

the Columbia Basin Region in Washington State. The Melgren’s

pivot-irrigated farm, located just east of Othello attracts lots of

long glances as drivers pass by. That’s because they planted 28

acres (seven acres per corner) of hybrid poplars in the corners of

a center pivot field. Water is supplied to the trees by drip irrigation. The tree stands range from four- to five-years-old, are

spaced 18 feet by 18 feet apart, are pruned to 18 feet, and are

between 30 and 50 feet tall. Diameters range from eight to 10

inches and should average 14 to 16 inches by age 10. These

plantings originated because the Melgren’s were tired of fighting weeds in the pivot corners of their wheat, potato, sugar beet,

and onion fields. Grass is planted between the rows to help control weeds during establishment. 

In June, 2000, the Melgren’s met with foresters from the

Natural Resources Conservation Service (NRCS) and the USDA

National Agroforestry Center (NAC) to discuss additional

incentive opportunities, future management, and marketing

alternatives. Some of these include carbon credits for poplar

plantations, incorporating additional agroforestry practices, such

as harvesting the grass between the rows for hay/forage, and

helping to develop poplar growers associations to distribute

information on poplar culture

and markets. 

In one pivot corner, the tree

canopy is beginning to shade

the ground and has reduced the

Poplar stands in pivot corners

provide a viable economic

product, wildlife habitat, some

wind protection for crops, and

an aesthetic quality to the

landscape.
The following scenarios describe the

potential for carbon storage in tree stems and

branches over a 20-year period. Roots are not

included, but would likely add from 15 to 25

percent to the totals. In addition, windbreaks

typically function effectively for 50 to 70 years

and would continue to accumulate carbon over

the life of the planting.

21.2 million metric tons of carbon dioxide (CO2) at age 20. 

In addition to carbon stored in windbreak trees, the protection provided by

the windbreak results in energy savings from reduced fuel use. In the case of

field windbreaks, land removed from agricultural production results in less fuel

use. Based on an average of five gallons of diesel fuel per acre for most crops,

planting 60,000 acres to windbreaks would reduce fuel consumption by

300,000 gallons annually.

Field Windbreaks

Field windbreaks reduce evaporation and plant

transpiration rates such that crop yields in a

field are typically increased, even though a portion of the field has been converted to windbreaks. Research has estimated the optimal tree

planting levels at between three and six percent of

the cropped field area. There are 210 million acres

of cropland unprotected by windbreaks in the North

Central U.S. and of this, 30 million acres are subjected to wind erosion in excess of the soil loss tolerance rate. Each million acres of planted windbreak would represent 200 million trees storing

Carbon

continued from page 1

Fall/Winter 2000/2001 | Inside Agroforestry 9

Farmstead Windbreaks

Of the more than 800,000 farms in the North Central U.S., over 300,000 have

no wind protection. For farmsteads located in cold climates, windbreaks have

been shown to reduce home heating requirements by 10 to 20 percent.

Assuming an average home uses 2,350 gallons of propane per heating season,

a 15 percent savings would reduce annual demand by 10.6 million gallons.

While this benefit would not begin until the windbreak reached an effective

height (about 10 years) it would continue throughout the remaining life of the

windbreak, typically 40 to 50 years. Over this period fuel savings in excess of

290 million gallons could be expected.

Living Snowfences 

In North Dakota, South Dakota, Nebraska,

Minnesota, and Iowa there are over 460,000 miles

of roadway. Many of these would benefit from protection with a living snowfence. Properly designed

living snowfences can dramatically reduce the need

to plow and re-plow roadways. Assuming a 1/3

reduction in snow removal costs, fuel usage for

every 1,000 miles of protected roads could be

reduced by 320,000 gallons annually.

Within 20 years field windbreak storage could

exceed 215 million metric tons of CO2

Planting windbreaks around these 300,000 unprotected farms would result in 

120 million trees (approximately 400 trees per home) storing 

13 million metric tons of CO2 within 20 years.

For each 1,000 miles of roads

protected by windbreaks two

million conifers could be

planted to store 175,000 metric tons of CO2

within 20 years.
like the first thing you would have to do is to determine how much

carbon you already have on your farm. All above- and below-ground

vegetation, including mineralized and organic matter in the soil, and

soil organisms must be taken into account to determine your carbon

baseline. Then you will need a management plan to show how much

carbon you can expect to store for a given time-frame. It is the difference between the base line and the projection that becomes your carbon offset and will be the basis for carbon credit payment.

Art: That sounds complicated. How am I supposed to do all of that?

Rich: It is going to be complicated to evaluate various carbon projects, each requires a different plan that must be presented in a large

enough quantity to justify registration, verification, and authentication.

Some feel that there is going to be a whole network developed to run

and market carbon credits. Carbon credit project managers would

assist landowners with specific carbon-types and present management

plans and acres to a ‘third party’ (Aggregator) who would group the

projects by type and register the acres so that a buyer knows what they

are getting. A carbon broker (CERC Creator) would then be able to

market carbon either directly to companies seeking credits or on the

open market.

Wayne: What do you mean by authentication? 

Rich: The marketing of CERC’s could be part of a worldwide trade

system using a Registry to track and identify credits in order to protect

both you and the buyer. Once a project manager has determined your

baseline, management plans, and estimated carbon a third party (probably a State-wide Organization) would review the carbon baseline

measurements and calculations for accuracy. Once the project is

authenticated as a feasible project the acres, management plan, and all

calculations would be entered into a third party registry (RegionalNational-International). 

Wayne: How would I prove that these changes are working so that

I can get paid? 

Rich: To make this process work a third party (state-wide

Organization) could periodically check the actual carbon against the

management projection and report back to the carbon broker.

Adjustments may need to be made in your management plan if you’re

not meeting your goal or your payment may need to be increased if

you’re exceeding your goal.

Wayne: What if after all is said and done, there is a fire or other

natural disaster? Will I have to pay for the additional carbon that is

lost as well as my base-line carbon?

Rich: That could be a problem. However, it sounds like in this system that the carbon credit broker would work with a third party actuary to determine the risk factor and provide insurance for any loss of

carbon. 

Wayne: Sounds like I might

be interested. Where do I go for

more information?

Rich: This is still pretty new

and there is a lot that has to be

worked out yet. There’s new

information coming out all the

time. A good place to start

though is at the recently developed Carbon Technology

Transfer Center. Their web site

is: www.carboncenter.net;

phone: 509-893-8065, or e-mail:

janet@pacrimrc-d.com or

tim@carboncenter.net

10 Inside Agroforestry | Fall/Winter 2000/2001

The Pacific Islands have a rich tradition of agroforestry,

building diverse and highly productive agricultural systems

with a variety of strategies and species. Agroforestry Guides

for Pacific Islands is now available and provides userfriendly, practical information on planning and installing a

number of important agroforestry practices. The book draws

on both time-tested, traditional Pacific Island agroforestry

strategies and modern research in the region. Agroforestry

Guides for Pacific Islands is written by and for agroforestry

practitioners, field-level extension workers, and farmers.

Agroforestry Guides for Pacific Islands is published by

Permanent Agriculture Resources (PAR) with support from

the Western Region Sustainable Agriculture Research and

Education (WSARE) Program. 

Individual guides can be downloaded from the

internet at: www.agroforestry.net. Or, contact PAR at:

P.O. Box 428, Holualoa, HI 96725; Phone: 808-324-4427;

e-mail: par@agroforestry.net

“Wow! It is like having an agroforestry

library and librarian

at your finger tips.

The book is well

researched and organized and the individual self-contained

chapters will be of

great value for extension and education.”

Now Available! 

Biotechnical Streambank

Protection Measures Workshop

April 4-5, 2001

A two-day workshop will be held at Arbor Day Farm in

Nebraska City, Nebraska. The workshop will consist of one day

of classroom instruction followed by a day in the field learning

how to install the measures. For more information e-mail Nancy

at: nhammond@fs.fed.us or fax her at 402-437-5712 to request

a registration form.

Agricultural

Development in the

American Pacific

(ADAP) Project

James R. Hollyer,

Project Manager:

University of Hawaii,

Honolulu, Hawaii

Conversation

continued from page 3

For more information on climate

change visit the

World Resources

Institute website at

www.wri.org/wri/climate. One

article of particular interest is

“A Climate and Environmental

Strategy for U.S. Agriculture”

by Paul Faeth and Suzie

Greenhalgh. This can be found

at www.wri.org/wri/sustag/

break_green.html.
Fall/Winter 2000/2001 | Inside Agroforestry 11

thesis, hybrid poplars can store a large amount of carbon in their

wood in a short period of time. There is also good evidence that

poplars significantly increase soil carbon, thus providing another

long-term carbon storage system. As companies look to become

“carbon neutral,” they may begin paying farmers and landowners

to grow hybrid poplars for carbon sequestration. A company is

considered to be “carbon neutral” when the amount of carbon

dioxide released into the atmosphere during their operations is

offset by some atmospheric carbon dioxide absorption method

like a poplar plantation.

Poplars and Water Quality

Clean water continues to be a major issue in the United States.

One way to improve and maintain water quality in wetlands,

lakes, and streams is to plant vegetative buffers that include

hybrid poplars. Poplars are native and well adapted to many of

these riparian areas. The plants in vegetative buffers, including

poplars, help stabilize stream banks, take up excess nutrients and

break down pesticides in surface and sub-surface water from

adjacent cultivated fields before they reach streams or other bodies of water. When poplars are used they can be harvested in 8 to

10 years. For example, if a 50 to 80 feet wide buffer is applied

using hybrid poplar, a 20 to 30 feet wide zone immediately next

to the stream could be left unharvested to protect water quality.

The remaining 30 to 50 feet wide portion of the buffer could then

be managed for periodic harvesting and income for the

farmer.

Poplar

continued from page 5

A national network of experts have come together to

provide technical support for individuals, private companies, city, county, state and federal agencies interested in

using fast growing tree species for wastewater treatment

and other similar types of tree-related environmental projects. 

Eventually a hardcopy manual will be developed, as

well as an internet website. The website will be updated

and provide direct links to identified experts.

For More Information, contact: Jon D. Johnson, Ph.D.,

WSU-Puyallup, 7612 Pioneer Way E., Puyallup, WA

98371. Phone: 253.445.4522; e-mail: poplar@wsu.edu

Poplar-Willow 

Technology Network

Forest Stand

(Schlaegel, 1984)

5 10 15 20 25 30 35 40

Stem diameter (in centimeters) at 1.37m

1.0

0.9

0.8

0.7

0.6

0.5

0.4

0.3

0.2

0.1

0.0

Total volume in m3

Predicted from shelterbelt 

equation. (Zhou, 1999)

Predicted from forest 

stand equation. 

(Schlaegel, 1984)

Above-ground volume of green ash

(includes stems and branches)

Pictured above Dr. Xinhua Zhou, University of NebraskaLincoln, takes measurements of a windbreak tree. This

tree is part of a study to determine the distribution of

mass in the above-ground portions of trees. Studies like

this one are helping to quantify how much carbon is

actually stored in trees and shrubs. Zhou has found that,

in the species studied so far, trees grown in windbreaks

contain more wood than forest grown trees of the same

diameter; as much as double the amount. This can be

attributed to the increased size of tree branches in windbreak-grown trees. This information can help landowners

determine how to take advantage of the potential carbon

credit benefits of agroforestry along with conservation

and production benefits.

How much

carbon is in a tree?

Volume 

proportion 

for green ash

Two-Row

Shelterbelt 

(Zhou, 1999)

Discovering Profits in Unlikely Places:

Agroforestry Opportunities for Added Income

...is a new publication that helps you search for profit niches on your farm. It discusses the potential of incorporating

Agroforestry practices for profit. It was written by Scott

Josiah and produced by the University of Minnesota

Extension Service, CINRAM, and MISA. For a copy email: order@extension.umn.edu or credit card orders at

800-876-8636.

Stem 48% Branch 52%

Branch 18%

Stem 82%
National Agroforestry Center

East Campus-UNL

Lincoln, Nebraska 68583-0822

PRSRT STD

POSTAGE & FEES PAID

USDA — FS

PERMIT NO G-40

March 6-8, 2001

Social Issues and the Environment, 

Nebraska City, NE. Contact the 

National Arbor Day Foundation, 

phone: 888-448-7337.

March 28-29, 2001

Second Carbon Sequestration and 

Biomass Energy Conference, 

Sacramento, CA. Contact Jim 

Vancura, phone: 530-397-7463; 

James.Vancura@ca.usda.gov

April 4-5, 2001

Biotechnical Streambank Protection 

Measures Workshop, Nebraska City, 

NE. Contact Nancy Hammond, 

fax: 402-437-5712;

nhammond@fs.fed.us;

April 7, 2001

Opportunities in Agroforestry, 

LaCrosse, WI. Contact Steve, phone:

608-348-3235; 

steve.bertjens@wi.usda.gov; 

April 24-26, 2001

Agroforestry and Forest Management

Learning Community Workshop. 

Arnot Forest Cornell University, 

Official Business

Penalty for Private Use, $300

Ithaca, NY. Contact Louise Buck: 

leb3@cornell.edu.

May 1-3, 2001

Urban Wildlife Management 

Conference, Nebraska City, NE. 

Contact the National Arbor Day 

Foundation, phone: 888-448-7337.

August 16-18, 2001

Seventh Conference on Agroforestry 

in North America. Regina, Sask., 

Canada. Contact John Kort, phone: 

306-695-2284, kortj@em.agr.ca,

agr.ca/pfra/aftappfa.htm

Agroforestry | Fall/Winter 2000/2001 Inside

Upcoming Events

Inside Agroforestry is published quarterly by the

USDA National Agroforestry Center. 

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

Greg Ruark, Center Director ext. 27

Michele Schoeneberger, 

FS Research Leader ext. 21

Rich Straight, FS Lead Agroforester ext. 24

Bruce Wight, NRCS Lead Agroforester ext. 36

Kimberly Stuhr, TT Specialist/IA Editor ext. 13

Ryan Dee, TT Assistant ext. 14

Mike Majeski, FS Agroforester

St. Paul, MN phone: 651-649-5240

Jim Robinson, NRCS Agroforester 

Fort Worth, TX phone: 817-509-3215

Gary Kuhn, NRCS Agroforester 

Spokane, WA phone: 509-358-7946

Web Site: www.unl.edu/nac

The National Agroforestry Center (NAC) is a partnership of the USDA Forest Service, Research

& Development (Rocky Mountain Research Station) and State & Private Forestry 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 partners and cooperators to conduct research, develop technologies and tools, establish demonstrations, and provide useful information to natural resource professionals.

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.

Mission