Inside Agroforestry | Summer 2004

Tool Talk



"If your only tool is a hammer, you tend to see every problem as a nail." 
- Abraham Maslow

Most would agree that having the right tools on hand can make just about any job 
easier. Ever try to cut a tree down with a sledgehammer? You’d probably find 
that an ax would make that chore a whole lot easier.

Along with ease, the right tools can also help save time and money. It's well 
worth the effort to keep abreast of new technology. For example, today, a chain 
saw, or even a feller-buncher, is probably the tool of choice when cutting down 
a tree. 

In this issue of Inside Agroforestry, you’ll find that numerous tools exist for 
you to use when designing agroforestry plantings. It's difficult to imagine what 
a tree planting might look like in 20 years. But with CanVis, a new visual 
simulation tool developed by NAC, you can digitally alter photos to illustrate a 
proposed design alternative. And, if you have to wait 20 years, you probably 
want to make sure your windbreak will meet your expectations. Using WBECON 
(WindBreak ECONomics) computer program, you can calculate the economics of a 
crop field with windbreaks, all while taking into account various factors, like 
windbreak species and design, soil and climate, crop rotation, yields, and 
prices.

Here's a chance to get some new agroforestry tools for your tool bench!



NAC Director's Corner
A commentary on the status of agroforestry by NAC Director, Dr. Greg Ruark

1st World Congress of Agroforestry


Participants from 82 countries gathered in Orlando, Florida from June 27 to July 
2, 2004 for the 1st World Congress of Agroforestry. Over the past 25 years 
significant progress has been made in building a scientific foundation for the 
design, installation, and management of agroforestry systems. The resultant 
gains in crop production and diversification, economic performance, and 
environmental benefits serve to illustrate the value of agroforestry research 
and technology development efforts and argue for the need to expand our gains to 
better meet societal demands.  

The Congress produced two books that document the current state-of-knowledge and 
practice of agroforestry worldwide.  These books have already been published 
and they provide valuable resource tools for those wishing to further explore 
the potentials of agroforestry. The 1st World Congress of Agroforestry Book of 
Abstracts (426 pages) contains summaries of the talks and poster sessions and 
represents the collective endeavor of hundreds of researchers, extensionists, 
landowners, students, and others involved in agroforestry.  The second book is 
titled New Vista in Agroforestry: A Compendium for the 1st World Congress of 
Agroforestry, 2004 (480 pages) and it offers a state-of-the-art synthesis of 
agroforestry as it applies to a broad array of topics in both temperate and 
tropical ecosystems.

More details on how to acquire these books can be obtained on the conference 
website at 	http://conference.ifas.ufl.edu/wca.



"When people can estimate the costs of changing their minds before they install 
a practice, we are more likely to see conservation on-the-ground ten years 
after the installation." - Madalene Ransom, NRCS Economist


Critics say, "Two thumbs up... Buffer$ pay!"

Gary Bentrup, Research Landscape Planner, Lincoln, Nebraska


"Buffer$ allows me to quickly calculate an economic return on buffers, saving 
me valuable time with landowners" says Don Ulrich, a conservation professional 
with the Natural Resources Conservation Service (NRCS). In the previous issue 
of Inside Agroforestry, we presented Buffer$, a spreadsheet-based application 
developed by the USDA National Agroforestry Center (NAC) to assist landowners 
and planners in analyzing the cost-benefits of conservation buffers. Buffer$ 
can calculate potential income from a buffer using cost-share programs, growing 
agroforestry specialty products, and incorporating other income opportunities. 
To aid in decision-making, the tool can compare potential income generated 
between a buffer alternative and a cropping alternative. 

Although recently released, this tool is already gaining popularity with 
conservation professionals because it has an easy-to-use interface. Buffer$ 
uses state average NRCS costs for installation and maintenance budgets and 
county soil rental rates for calculating program payments. Default values from 
Nebraska are used to demonstrate the tool. You can easily customize the tool 
for your area by entering your NRCS state average costs and local county soil 
rental rates. Buffer$ can be downloaded from the NAC's website www.unl.edu/nac/		
conservation/ and requires Microsoft Excel to run. A free CD with Buffer$ 
can also be requested by contacting NAC at (402) 437-5178.
	


Adding up the benefits
Software calculates the economic potential of windbreaks


Field windbreaks reduce wind speeds for a distance of 20 to 30 times their own 
height (H) and increase crop yields out to about 15H. Although they compete 
with crops within their root zone (about 1H) and take land out of production, 
at maturity, the overall production increases at the field level usually 
outweigh any localized decreases.

The computer program, WindBreak ECONomics (WBECON), was created to calculate 
the economics of field windbreaks over their lifespan. WBECON is a useful tool 
for natural resource professionals and landowners. It calculates the economics 
of windbreaks taking into account various factors such as species and 
characteristics, design, soil and climate factors, crop rotation, windbreak 
costs, crop costs and crop prices. For each year of the windbreak's life, from 
the time of planting or from a specified age, costs and benefits are calculated. 
Costs include windbreak establishment, maintenance, and removal, yield losses 
due to competition, and land taken out of production. The benefits are crop 
yield increases for each year and reduced input costs. Other economic benefits, 
such as soil erosion control and crops from windbreak trees, are not considered 
in the program.

The user enters the following information:
- Soil texture, moisture condition, and prevailing wind
- Crop rotation (for up to five years), production costs, crop prices, expected 
  yield without shelter
- Field dimensions
- Windbreak species, placement, and number

After the user has entered all of the necessary information, the computer does 
the calculations.

The output summarizes inputs and assumptions used in the calculations. The 
program calculates the annual benefits of the windbreak at maturity in constant 
dollars. Most importantly, the windbreak’s Net Present Value (NPV) is 
calculated. NPV is the net benefit over the windbreak's life-span in which the 
benefit calculated each year in constant dollars is discounted at an annual 
discount rate to account for real interest rates. For example, at a five 
percent discount rate, $100 earned at the beginning of the first year has a 
present value of $100 but $100 earned one year in the future has a present 
value of only $95. The NPV is important because it permits a realistic 
comparison of windbreaks which have different life-spans and growth rates.

It is easy to change windbreak design, crop rotation, and other factors and 
recalculate the economic benefit. This allows the user to try out different 
scenarios and assess the sensitivity of NPV to changes in inputs. 	

For more information or to get a copy of WBECON, contact Jim Brandle at 
jbrandle1@unl.edu or, in Canada, John Kort at kortj@agr.gc.ca.



GIS: Mapping opportunities for agroforestry

Gary Bentrup, Research Landscape Planner, Lincoln, Nebraska


Agroforestry opportunities are being identified using geographic information 
systems (GIS), a collection of computer hardware and software used to analyze 
and display geographically referenced data. Using readily-available data layers 
like soils, slope, and land cover, suitable locations for agroforestry 
practices can be identified. 

In the Pacific Northwest, fast growing hybrid poplar are being increasingly 
used by the pulpwood industry. To assist landowners who are considering 
diversifying their operations with poplar, optimal growing sites need to be 
identified. Dave Hoover, State GIS coordinator for Idaho NRCS, analyzed 
regional soils data using GIS to find the most suitable sites in the Pacific 
Northwest for hybrid poplar.

At the Center for Subtropical Agroforestry (CSTAF) located at the University of 
Florida, researchers have been developing an online GIS database to help 
landowners and agroforestry practitioners select plants for southern 
agroforestry systems. The Southeastern Agroforestry Decision Support System 
(SEADSS) allows users to select an area of interest and view information on 
soils, land use, climate, and other data. Based on these data, the tool 
provides a list of agroforestry plants suitable for the site. Because the GIS 
tool is linked to a plant database, a user can quickly find out more 
information on the recommended plants, including management and propagation, 
products and services, and species photos. The tool is currently being 
developed for counties in Florida. Future plans include developing SEADSS for 
Alabama and Georgia. More information can be found at 
http://cstaf.ifas.ufl.edu/SEADSS.htm.

The most significant benefit of using GIS in agroforestry is the ability to 
combine different assessment results to simultaneously address rural landowner 
and community issues. Landowner goals, like minimizing soil erosion and 
providing crop diversification, may be accomplished by just focusing on site 
conditions, however to solve community-driven goals like water quality and 
wildlife habitat requires a larger scale perspective. GIS can provide a way to 
integrate these different concerns by efficiently combining information from 
different scales.

At the USDA National Agroforestry Center (NAC), multi-scale GIS-guided 
assessments are being developed for water quality, wildlife habitat, soil 
protection, and agroforestry specialty products for the western corn belt 
ecoregion of the U.S. The individual assessments are then combined to identify 
where several objectives can be accomplished with agroforestry practices. For 
instance, one of NAC's assessments has identified perennial vegetation gaps in 
riparian corridors that could be restored to facilitate wildlife species 
movement and provide surface runoff filtration. Another assessment has 
identified suitable locations where decorative woody florals, like curly willow 
and pussy willow, can be grown. University of Nebraska researchers have shown 
potential annual net returns ranging from $400 to $3500 per 1000 feet at four- 
to six-foot plant spacing. By combining these assessments results, areas are 
identified where riparian buffers can be located to improve habitat connectivity 
and protect water quality while offering landowners the option to grow a 
product for profit. More information can be found at 
www.unl.edu/nac/conservation/.

Depending on the scale of analysis, GIS-guided assessments can support 
conservation policy and program development, prioritize projects, develop 
technology transfer programs, guide additional research, and influence 
site-scale planning and design. Many states have internet-accessible GIS data 
clearinghouses providing free spatial information, and skilled GIS technicians 
can now be found in many state and county-level resource management agencies 
which may be able to provide assistance. Promoting acceptance, support, and 
adoption of agroforestry will be easier with GIS mapping the way.



Pixel this: Visual simulations aid in resource planning

Gary Bentrup, Research Landscape Planner, Lincoln, Nebraska


"What will it look like?" Natural resource professionals often hear those words 
from landowners who have difficulty picturing a proposed agroforestry tree 
planting or conservation plan. Planting plans and engineering drawings, while 
necessary documents, often mean very little to the general public. Landowners 
lament that if they could only see a picture of the final project. 

Now resource professionals have a visual simulation tool to illustrate their 
design ideas. Visual simulations are images that have been digitally altered to 
illustrate a proposed design alternative. Digital photos of the landowner's 
property can be acquired by scanning photographs or taking pictures with a 
digital camera. Using image-editing software, the proposed design can be 
"created" by adding images of trees, shrubs, grass, and other materials onto 
the base image of the landowner's property. In a relatively short time, 
windbreaks, riparian buffers and other conservation practices can be depicted 
in rural and urban environments.

In addition to communicating ideas and design alternatives, visual simulations 
can be used to engage the public in the design and decision-making process. For 
example, a Wisconsin community was opposing a proposed flood control dike 
because they had difficulty visualizing how it would impact a local park. 
Visual simulations were used at public meetings and in the newspaper to better 
explain the proposal. Once the public saw the proposal, there was overwhelming 
support for the project.

Visual simulations can be used as a marketing tool for new programs and as a 
training aid to help new employees visualize new concepts.

To facilitate the use of visual simulations in agroforestry and conservation 
planning, the USDA National Agroforestry Center (NAC) is creating a manual to 
show users how to create realistic and accurate simulations. The manual will 
provide detailed information on acquiring images and how to edit the images 
using a variety of available software programs. The core of the manual will 
focus on how to size and locate plant materials and other objects in the images 
using perspective and scaling principles. Using the manual, resource 
professionals will be able to gain the skill and confidence that the 
simulations they create are accurate depictions of the proposed design 
alternative. See NAC’s website, www.unl.edu/nac/conservation/, for the manual 
availability this fall.


CanVis: Image editing for resource planning

Visual simulations can be created using software programs like JASC PaintShop 
Pro and Adobe Photoshop Elements. While these programs are quite powerful for 
creating simulations, they can take some time to learn how to use them. In 
response, NAC has developed a software program that allows resource 
professionals to create realistic simulations with minimal computer skills. One 
of the main benefits of CanVis is its collection of object libraries that 
contain images of plants materials, agricultural features, people, and urban 
park elements that can be quickly added to the base image. This saves users' 
valuable time by not having to create plant and other images from scratch. 
Some of the other tools available in CanVis include adding shadows and text, 
cloning textures, and adding hardscape elements like pathways and walls. This 
program will be available this fall. For more information, check NAC's website 
www.unl.edu/nac/conservation/.



It's sedimentary: EBA/FRA=efficiency
Moving from generality to specificity in buffer assessments


According to data from the USDA Farm Services Agency (FSA), over 1.5 million 
acres of riparian forest buffers and filter strips have been installed on 
American farmlands through the CRP program. Most of these buffers have been 
installed according to general program guidelines and not necessarily custom 
designed to the site specific soils, slope, and vegetation cover or even 
modified with respect to other upland conservation practices on the same fields. 
Consequently, we as resource professionals need a way to evaluate riparian 
buffer function in order to know that our conservation program dollars are 
being used effectively.

With these issues in mind, Mike Dosskey, of the National Agroforestry Center 
and Matt Helmers, Dean Eisenhauer, Tom Franti, and Kyle Hoagland, all of the 
University of Nebraska, set about to develop a field-based approach for 
assessing the sediment trapping efficiency of riparian buffers. It has been 
long recognized that the concentration of runoff flows reduces the 
effectiveness of riparian buffers because only a portion of the buffer will 
interact with the field runoff. This group of researchers devised a visual 
buffer evaluation system that takes into account the effects of concentrated 
flows, without requiring lots of expensive monitoring equipment and time. 

They found that the relationship of the "effective buffer area" (EBA), that 
area of the buffer that actually receives runoff, to the "field runoff area" 
(FRA), that area of the field that contributes runoff through the buffer, is a 
very good indicator of the buffer’s sediment trapping efficiency (see Figure 
One). 

The field runoff area is delineated by walking the field margins adjacent to the 
buffer examining the topography, microrelief, and patterns of erosion and 
deposition of soil and crop debris. 

The effective buffer area estimation is more subjective and requires careful 
interpretation of the runoff flow path from the field area and into and across 
the buffer to the stream. One of the most critical areas to examine is the 
field margin where sediment deposits and tillage berms often direct runoff to 
flow and concentrate along the edge of the buffer for relatively long distances 
before finally entering the buffer (see Figure Two).

The visual indicators of the runoff flow direction are far easier to find in 
the spring before buffer vegetation gets to tall and the crop closes canopy 
over the field. This visual approach to assessing sediment trapping of buffers 
is relevant for 10-year rain events or larger. Although this appears to ignore 
more frequent rain events, the researchers believe that the 10-year event is a 
good indicator of runoff patterns. 

More details can be found in the article, Assessment of concentrated flow 
through riparian buffers, Journal of Soil and Water Conservation. 
(2002) 57: 336-343.



Is your BMP working?
Protocol helps to protect our nation’s water resources


Best Management Practices or BMPs have become a part of our conservation 
language as a result of the 1987 Clean Water Act (CWA). The CWA has identified 
BMPs as the primary means to address non-point source water pollution. The 
Environmental Protection Agency (EPA), is required to show evidence of 
enforcement and has long sought a standard BMP monitoring protocol to provide 
measurable data that are reliable and comparable among states. As a result, 
many states, universities, federal agencies, companies, and organizations have 
developed BMPs to guide their land use management activities. 

The forest management community is no different. In fact, the term BMP was 
defined to refer to precautionary activities designed to protect water 
resources during timber harvests. It is in the best interest of those involved 
in timber harvesting activities to effectively use BMPs because then they are 
exempt from permitting requirements under the CWA. 

However, individual state monitoring has been sporadic, qualitative, and only 
marginally acceptable as a measure of effectiveness. State Forestry agencies 
have sighted manpower, time, cost, reluctance to change their individual BMP 
specifications, and monitoring team makeup as barriers to acquiring a common 
protocol. 

The Northeastern Area Association of State Foresters, Water Resources Committee 
(NAASF), using a grant from the U.S. Forest Service has initiated a project to 
create a regional BMP monitoring protocol. The protocol focuses on water 
crossings and riparian areas as having greater potential to adversely impact 
water resources. Evaluating BMP principles, incorporating a quality control 
system, and recording impacts on GPS units will overcome state agency barriers 
and permit evaluation by watershed, political or other boundaries. Quantitative 
data will permit computer modeling and provide a meaningful foundation for risk 
and impact analysis and a defensible measure of the impact of forest management 
activities on water resources.

Since Version 1, the monitoring protocol has been through two seasons of field 
testing in 10 northeastern states and the equipment cost was reduced by a 
factor of ten when the protocol was adapted for use in PDAs Pocket PCs and 
Trimble units using Pendragon and Windows software. Several western states are 
also looking at this protocol for evaluating timber harvesting activities in 
their regions.

Although this monitoring protocol has been developed to evaluate timber harvest 
activity BMPs, the protocol may become the foundation for evaluating other land 
use BMPs.

Adapted from A Protocol for Monitoring Best Management Practices, USDA Forest 
Service Northeastern Area bulletin.



Agroforestry tools: The spherical densiometer


In agroforestry, it is often important to manage the tree over story canopy 
density in order to produce the desired crops in the under story. This is 
especially true for the practices of silvopasture, forest farming, and, in some 
instances, alley cropping. 

Canopy has often been calculated using ocular estimates which have been shown 
to be neither accurate nor reliable by two different people. The spherical 
densiometer is a simple, inexpensive tool that will often meet the needs for 
collecting canopy estimates. It is essentially a convex, circular mirror 
etched with a grid that divides the mirror into 24 squares.

To use a densitometer:
- Hold instrument level, with the mirror pointing up, 12 to 18 inches in front 
   of body and at elbow height.
- Assume four equal-spaced dots in each square on the grid and systematically 
   tally the dots covered by canopy material.
- Total dot count equals the percent canopy closure. 
- Make four readings per sample point-facing North, South, East and West.

This will provide a reliable estimate for managing canopy density in 
agroforestry systems.