Developing Production Techniques and A Site Assessment Tool for Forest Farmed Ramps in Appalachia

The Allium tricoccum Aiton (ramps, aka wild leeks), a native spring ephemeral, is a cultural keystone species in Appalachia, a mountainous physiographic region encompassing 205,000 square miles of the eastern United States. People in Appalachia have long harvested ramps in the wild. However, growing demand for the plant in and outside the region has increased harvesting, resulting in threats to native populations. Agroforestry cultivation techniques and technical support for sustained-yield forest farming practices are needed to conserve ramps and meet increasing demand. Various techniques for assessing suitable production practices for ramps were explored in this dissertation, particularly examining best-suited ramp ecotypes, mycorrhizal treatment, and habitat suitability determination. In the first study, bulbs and seeds from diverse Appalachian locations were gathered and transplanted to a common experimental site to investigate the effects of different ramp ecotypes on growth, survival, and stress responses. Plant characteristics and stress measurements were recorded before transplantation and post-transplantation assessments. Specifically, the study investigated the germination rate of three ramp seed ecotypes and the growth, survival, and stress responses of eight native ramp bulb ecotypes and three commercially obtained seedling samples. Results indicated that above-ground growth, survival, and stress response on the ramp ecotypes differed significantly. The second study explored the impact of mycorrhizae on ramps and was evaluated by assessing the impact of Arbuscular Mycorrhizal Fungi (AMF) inoculation on Allium tricoccum. Four measurements, collectively referred to as parameter categories, were assessed. These included measures of 1) above-ground plant growth: leaf length, and leaf width; 2) stress measurement: transplant stress after a few days of transplant, and photosynthetic performance stress after a year of transplant; 3) survival analysis; and 4) mycorrhizal colonization rate. For each parameter category, three treatment comparison categories were conducted: 1) Positive control treatments: bulbs were planted from their native environment without treatment; 2) Negative controls: bulbs were treated with fungicide before planting to eradicate existing AMF in roots; and 3) The test group: bulbs were inoculated with commercial AMF (Atriva 500). Results indicated that mycorrhizal inoculation could increase ramp leaf length (P≤0.03). However, the impact varied by ecotype, highlighting the importance of considering local environmental conditions and ramp ecotype. Mycorrhizal inoculation did not impact ramp growth at the seedling stage. Mycorrhizal treatment increased the transplanted ramp's survival and stress tolerance (P≤0.001). The third study used multi-criteria decision-making (MCDM), the Analytic Hierarchical Process (AHP), and weighted linear combinations to model suitable habitats for ramps production. Ten habitat criteria were chosen (including five soil properties, three topographic parameters, and two land use properties) to assess the potential for growing ramps in seven counties in Virginia, West Virginia, Pennsylvania, and North Carolina. The percentage of highly suitable areas for ramps production in the studied counties ranges from 21.5% in Haywood County to 49.6% in Macon County. Similarly, moderately suitable areas range from 36.7% in Macon County to 54.5% in Lawrence County. Ground truthing was performed to validate the model. Ramp patch locations within each county were geocoded in the final suitability maps. Existing ramp patches were within the model's estimate of moderate to high site suitability ranges, suggesting the model is valid. Results of the study suggest that site suitability modeling could be useful for producers interested in growing ramps in forest farm settings across Appalachia.