UNIVERSITY PARK, Pa. — Ramps, also known as wild leeks, and their unique garlic-onion flavor profile, are a popular foraged seasonal food but that demand could drive overharvesting of the native forest plant. In response to excess harvest worries, an interdisciplinary Penn State research team has studied how to grow and harvest ramps as a potential forest crop since 2017. In their latest study, published in the journal Wild, they characterized ramp habitat for the first time in Pennsylvania, offering guidance for the agroforestry practice known as forest farming.

The researchers gathered field site data such as soil, topography and neighboring vegetation at 30 thriving wild populations across Pennsylvania and paired it with geographic information system site-level data for more than 100 additional populations to determine “ramp habitat” in the state. Plant species associated with ramps in natural settings were recorded as “indicators” for on-the-ground assessments of potential forest farming sites.

In the field, ramp populations were most frequently recorded in moist, bottomland positions, facing north, east or northeast. They are most often found under the following forest canopy trees: sugar maple, tulip poplar, American basswood, black cherry, bitternut hickory, northern red oak and American beech. The most frequent woody understory species associated with ramps in Pennsylvania are multiflora rose, Japanese barberry, spicebush, gooseberry blackberry, elderberry witch-hazel, choke cherry, grape vine and poison ivy. 

Taken together, the researchers reported, these results can help to guide practical site selection for forest farming.

“The agroforestry practice of forest farming may be a solution to conservation challenges surrounding the wild exploitation of this species, but it requires proper site selection to be successful,” said team leader Eric Burkhart, teaching professor in ecosystem science and management

For nearly two decades, Burkhart’s lab in the College of Agricultural Sciences has conducted research on the conservation, ecology and management of popular wild plants in Appalachian forests such as American ginseng, goldenseal, ramps, ghost-pipe and prickly ash. In the case of ramps, the increasing demand for the plant in recent years, Burkhart noted, has the potential to be detrimental to wild ramp populations in the future if not balanced by planting and stewardship, especially in parts of their range where they are less plentiful.

Ramps have specific growing requirements, and “not just any forest will do,” according to first author Ezra Houston, who earned a master’s degree in forest management from Penn State in 2022.

“Plants can tell you a lot about local site conditions within a forested landscape — especially because many slow-growing perennial forest understory plants tend to grow together in similar forest microhabitats,” Houston said.

Choosing the proper location to grow ramps can help reduce planting failures or poor performance, Houston explained.

“We hope that by using a combined modeling and field-collected data approach, we have produced information so that a prospective forest farmer could walk a forested site and quickly get an idea of whether it is a suitable spot for growing ramps or not,” he said, adding that the authors expect to disseminate these findings in less technical outlets such as extension education products and programs beginning in 2025.

Contributing to the research were Cassie Stark, who earned master’s degree student in forest resources at Penn State; Xin Chen, with the Appalachian Laboratory, University of Maryland Center for Environmental Science; and Sarah Nilson, assistant professor at Penn State Beaver.

The Pennsylvania Department of Conservation and Natural Resources, Wild Resources Conservation Program, funded this research.