Knowledge-Based Estimation of Edible Fern Harvesting Sites in Mountainous Communities of Northeastern Japan

Once local expert knowledge regarding the harvesting of various non-timber forest products (NTFPs) is lost, it is difficult to recover. We investigated whether the knowledge of expert forest harvesters can be used to determine the habitat distribution and harvesting sites of three popular edible wild ferns, i.e., ostrich fern (Matteuccia struthiopteris), bracken (Pteridium aquilinum), and royal fern (Osmunda japonica), in mountainous communities of western Fukushima, Japan. Using multi-criteria evaluation (MCE) based on the analytic hierarchy process (AHP) and geographic information system (GIS), we found that harvesters were easily able to recognize differences in the spatial characteristics of the habitat distribution of fern species due to both natural and anthropogenic factors. These factors were described by various GIS layers, such as vegetation and terrain features (e.g., gradient, aspect, and slope position) derived from a 20-m digital elevation model (DEM). Harvesting sites were limited by their distance from a roadway, which differed among species. By comparison with the GPS records of actual harvesting sites, we estimated the potential harvesting sites of each fern species with reasonable accuracy, particularly for bracken. Our results show that the knowledge of expert forest harvesters can be quantified using MCE and GIS, which is useful for determining the spatial characteristics of NTFP harvesting and ensuring sustainable management practices.