Agroforestry & Pollinators
Agroforestry Helps Pollinators Help You
By Jeanna Childers Leurck, USDA Forest Service, Forest Stewardship Program Manager
Farms in the U.S. today are larger and have less nearby habitat to support bees than in the past. Yet the need for pollinators in agricultural landscapes has never been greater.
Globally, the acreage of insect pollinated crops has more than doubled in the past 50 years. At the same time, commercial beekeepers in the U.S. are losing an unsustainable percentage of their hives of honey bees each year because of a combination of habitat loss, diseases and pests, and pesticide exposure.
Native bee abundance and diversity is challenged as well. Almost 25 percent of bumble bees are facing dramatic population declines. Ongoing research demonstrates that these native bees play a vital role in crop pollination, and their numbers can be increased through agroforestry and other additions to our agricultural landscapes.
USDA Agencies Taking Steps to Support Pollinators
The Natural Resources Conservation Service through the Environmental Quality Incentives Program has updated its Conservation Stewardship Program to provide incentives for pollinator habitat; the Agricultural Research Service has conducted research on pollinators and released guidelines for gardeners, and the US Forest Service uses collaborative landscape restoration projects to teach students about pollinators, along with many other activities.
One question many people are asking is: how can we incorporate more pollinator habitat into our communities, agricultural lands, and forests?
Landowners Can Support Pollinators
Private landowners can do a lot to help support pollinators by providing habitat and flowering plants that provide food for pollinators. One way is through agroforestry, the intentional integration of trees and shrubs into crop and animal farming systems. For producers of insect pollinated crops, pollinator habitat and floral diversity can pay dividends by improving crop pollination and reducing pest populations, while also supporting other types of production and natural resource conservation goals.
Agroforestry practices can be managed to add more flowering plants and nesting habitat to agricultural or community landscapes. The types of agroforestry and ways pollinators work within each type are described below to help understand the way they fit together.
Windbreaks or hedgerows help reduce wind speed, making it easier for pollinators to fly and visit flowers. When planted with diverse flowering shrubs and trees, windbreaks can provide shelter, pollen, and nectar for pollinators, other beneficial insects, and wildlife. Windbreaks and other linear plantings can serve as buffers to drifting pesticides. To be pollinator friendly windbreaks should not include plants that will attract pollinators when adjacent crops are sprayed. Planting wildflowers during establishment can enhance pollinator resources and reduce weed pressure.
Riparian Forest Buffers
Riparian forest buffers are especially important for bees and other pollinators during hot summer months when upland plants may not produce nectar or pollen. Early flowering willows, as well as fruit and nut-bearing shrubs like pawpaws, elderberries, and hazelnuts, can provide additional farm income as cut flowers or produce, while also providing reliable food resources for pollinators. Honey bees may also visit muddy shorelines to gather water for cooling their hives.
Silvopasture, the combination of trees with forage and livestock production, provides an open understory where a variety of flowering forbs, such as alfalfa, clover, or native wildflowers can be allowed to grow. Rotational grazing practices give these forbs an opportunity to recover from grazing or flower before being eaten. Flowering trees can be added to silvopasture systems, supporting pollinators while providing shade for livestock and a potential additional income source. Harvestable flowering trees, such as basswood, black locust, maple, or yellow poplar can enhance a silvopasture system.
Alley cropping presents an opportunity to grow plants in close proximity that have complementary flowering periods. By paying careful attention to bloom periods and using varied species, this system can provide nearly continuous pollen and nectar forage within a single farm. Consider flowering trees like black cherry, black locust, or basswood along with the more typical alley cropping trees of walnut, pecan, or oak. Diverse forbs and shrubs may be planted in rows for cut flowers, berry production, or the nursery market, as well as for pollinators. A legume forage crop between rows will not only fix nitrogen and help manage weeds, but also provide nectar and pollen for bees if allowed to flower.
Forest farming with valuable overstory crop trees, like yellow (tulip) poplar, maple, basswood, and black cherry provide excellent pollinator habitat. Cultivated understory plants, such as ginseng, goldenseal, and black cohosh, may benefit from pollinator visits.
Information for this article was adapted from the USDA National Agroforestry Center (NAC).
- Pollinators – USDA National Agroforestry Center: http://nac.unl.edu/issues/pollinators.htm
- Pollinator Conservation Resource Center – Xerces Society for Invertebrate Conservation: http://www.xerces.org/pollinator-resource-center/
- Pollinator Resources – Natural Resources Conservation Service: http://1.usa.gov/1VusKNf
- Pollinators – US Forest Service: http://www.fs.fed.us/wildflowers/pollinators/
- Pollinator Conservation – Ladybird Johnson Wildflower Center: http://www.wildflower.org/conservation_pollinators/