WASHINGTON, D.C. — The practice of combining tree planting with crops and livestock to protect soil, water and air quality – also known as agroforestry – is not favored by many farmers in the United States. The USDA is hoping to change that by establishing a partnership with its Canadian counterpart, and boosting support for agroforestry research and development.

“We’re not trying to convert fields into forests,” said Andy Mason, U.S. National Agroforestry Center (NAC) director. “Agro-forestry is about planting the right trees in the right place, for the right reason.”

Agroforestry encompasses everything from traditional windbreaks that protect soil, crops and livestock, to biomass production and other emerging practices that protect water and air quality.

According to the USDA, having trees interspersed with crops can help reduce erosion and topsoil loss, as well as improve water quality, since the roots act as a filtration system for pesticides and fertilizers. The trees are also beneficial to wildlife and serve as carbon storage.

The collaboration between USDA and Canada’s Department of Agriculture and Agri-Food aims to advance agroforestry science and develop tools to mitigate the effects of global climate change. To that end, NAC and Canada’s Agroforestry Development Centre will support the Global Research Alliance on Agriculture Greenhouse Gases. “One of the things we will work on with Canada is greenhouse gas accounting,” Mason said. “For example, with silvopasture, we will study how much carbon is sequestered by the trees and how much greenhouse gas is emitted by the livestock.”

Despite all the benefits to the environment, agroforestry is relatively rare in the United States, according to Jeff Dukes, associate professor of bioscience at Purdue University’s Department of Forestry and Natural Resources.

“There’s not a lot of support for it,” he said. “Traditional methods of agriculture and forestry have been favored over agroforestry, which is viewed as kind of complicated, especially with the bigger-size equipment. A lot of today’s equipment is sized to deal with massive acreage, and that makes intercropping and focusing on multiple species impractical.”

But Bruce Wight, national forester for the USDA Natural Resources Conser-vation Service, said there are many reasons why farmers should consider integrating tree plantings on their land.

“Whether you believe that climate change is manmade or not … agroforestry practices make the landscape more resilient to extreme events,” he said, pointing to studies showing that riparian quarters help protect croplands during floods.

Trees also help crops against the wind during droughts and provide shade for livestock.

Regardless of the conservation aspects, Mason added that agroforestry systems can be profitable.

“For example, if you decide to make a wider buffer, you can grow trees for biomass production,” he said.

Douglass Jacobs, professor of forest regeneration at Purdue’s Department of Forestry and National Resources, believes several factors determine if the initiative will be successful.

“The main thing is that it’s hard to break traditions, especially among farmers who are not accustomed to planting crops and trees together,” he said.

“Part of the challenge is to have people that can demonstrate that this can be a compatible system.”

He added there is a need for financial incentives as well as a big educational effort “to show some ways that farmers can benefit from both worlds.”

Depending on where the trees are planted, Jacobs said there are already some tax reductions and cost-share programs in place of which farmers can take advantage. And even though planting trees next to a cornfield will reduce the area available for that crop, agroforestry practices can be profitable for the landowner in the long term.

“Eventually you’ll be able to harvest the trees and recoup the investment,” Jacobs said. “The profit depends on the time frame. Some of the higher-value trees, like oak, ash, walnut and maple, may need 60 years before you can harvest. Lower-value species like spruces and pine are typically harvested on a shorter rotation, 20 to 30 years.”