For a long time, there’s been a common belief in many farming communities that trees and farming don’t belong together. However, agroforestry—a method that combines trees and shrubs into agricultural systems, such as using trees as windbreaks, incorporating them in pastures, or intercropping tree crops with annual crops—can offer numerous advantages for both farmers and the land. Unfortunately, in the U.S. Midwest, these advantages have largely been overlooked, resulting in very low adoption rates.
Researchers at the University of Illinois Urbana-Champaign highlight the need for strategic planning that takes into account environmental, social, and economic factors to promote agroforestry in the Midwest. Their recent study published in Environmental Research Letters lays the groundwork for this.
Lead author Sarah Castle, who conducted this analysis as part of her doctoral research in the Department of Natural Resources and Environmental Sciences (NRES) within the College of Agricultural, Consumer and Environmental Sciences at Illinois, stated, “While there has been plenty of research on the agronomy and ecology of agroforestry and its environmental advantages, we know relatively little about its social and economic effects. These factors can significantly alter our priorities for implementing agroforestry in specific areas.” Castle is now a postdoctoral researcher at Yale School of the Environment and a visiting scholar at Illinois.
Together with co-authors Chloe Wardropper, an assistant professor in NRES, and Daniel Miller, an associate professor at the University of Notre Dame, Castle aimed to develop a tool that identifies where agroforestry could yield the most environmental benefits while also being economically feasible, socially acceptable, and placed in areas where the relevant tree species would thrive best.
Combining data on social attitudes and economic viability with environmental information proved to be challenging, but the researchers successfully accomplished this task.
“We gathered various data layers, normalized them for consistency, and combined them purposefully to create a comprehensive assessment. Conducting interviews with key informants was particularly valuable,” Castle added. “We spoke with individuals from Illinois Extension, USDA’s National Agroforestry Center, the U.S. Forest Service, and the Savanna Institute, a key player in Midwest agroforestry, to gather insights on our methodology.”
Ultimately, Wardropper explained that the team produced a map pinpointing regions where agroforestry could significantly influence factors like soil erosion, water quality, climate, and profitability on lands unsuitable for other crops. They also provided an estimation of potential carbon sequestration if agroforestry were adopted on the most suitable land in the Midwest.
“If just 5% of suitable agricultural land in the Midwest adopted these practices, it could capture 43 million tons of carbon dioxide equivalent (CO2e) annually,” Wardropper noted. “This presents a considerable benefit compared to cover crops, which are estimated to store around 8.4 million tons of CO2e per year on the same types of land.”
Importantly, the researchers have made their mapping tool freely available for landowners, conservation scientists, and policymakers.
“The decision support tool we’re rolling out enables users to adjust all parameters in their suitability analysis,” Castle explained. “For instance, if someone wishes to focus on one specific tree species, consider only economics, or weigh economic factors significantly more than environmental ones, they can customize their parameters according to their agroforestry objectives and rerun the analysis to create tailored maps for different Midwest states, counties, and watersheds.”
Wardropper added that each agroforestry practice comes with its own spatial possibilities, allowing for a suitable method in nearly every region.
“There’s a distinction between edge-of-field practices like windbreaks and riparian buffers, and those that encompass the whole property or parts of it, such as alley cropping and silvopasture,” she observed. “It’s essential to realize that transitioning to agroforestry doesn’t need to entail a complete transformation of the entire farm.”
“There are numerous ways that a landowner or operator can customize agroforestry to align with the benefits they seek. For example, establishing a windbreak in a windy area of the Plains can be advantageous and could represent a lower investment and learning curve compared to moving to a practice like alley cropping.”
