Ramps, also known as wild leeks, and their unique garlic-onion flavor profile, are a popular foraged seasonal food, but that demand could drive over-harvesting of the native forest plant. In response to excess harvest worries, a multi-institutional research team has been studying how to grow and harvest ramps as a potential forest crop since 2017. In their latest study, published in the journal Wild, the team 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 the state and paired it with geographic information system site-level data for more than 100 additional populations to determine "ramp habitat." 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 the region 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 guide practical site selection for forest farming.
"By using Maximum Entropy, a machine learning algorithm widely used in species distribution modeling, we associated the occurrences of ramps with different environmental conditions including climate, soil, and topography and mapped the predicted probability of the species across geographical space," said Xin Chen, co-author on the paper and assistant research scientist at the UMCES' Appalachian Laboratory. "Such a map will provide useful information for prospective forest farmers about whether the environmental conditions at a site are suitable for ramps or not."
The lead researcher, Eric Burkhart of Penn State University, 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 for nearly two decades. In the case of ramps, the increasing demand for the plant in recent years 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," said first author, Ezra Houston. "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." Choosing the proper location to grow ramps can help reduce planting failures or poor performance.
The team hopes that by using a combined modeling and field-collected data approach, they 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. The authors expect to disseminate their findings in less technical outlets, such as extension education products and programs, beginning in 2025.
The Pennsylvania Department of Conservation and Natural Resources, Wild Resources Conservation Program, funded this research.
To read the paper, entitled, "Habitat Associated with Ramps/Wild Leeks (Allium tricoccum Ait.) in Pennsylvania, USA: Guidance for Forest Farming Site Selection," follow this link: https://www.mdpi.com/3042-4526/1/1/6
