The Sustainable Harvest of Wild Populations of Oshá (Ligusticum porteri) in Southern Colorado for the Herbal Products Trade

It is a challenge to both use and conserve wild-harvested medicinal plants, especially when it appears they may be threatened by harvest pressure, and there is often limited biological information available to inform management decisions. Osha (Ligusticum porteri) is an important medicinal plant whose roots are harvested in the southwest USA and Mexico as an herbal remedy to treat flu, sore throat, and other illnesses. We studied population structure, root production, and the ability of osha to recover from harvest in different environmental contexts at two high-elevation southern Colorado sites with a goal of understanding what a sustainable rate of harvest might be. We experimentally harvested roots of mature osha plants at four different rates. Results indicate that low rates of harvest allow for stable osha populations over the short term (3–5 year) at our sites. Due to management interest by the USDA Forest Service, we propose a possible sustainable harvest rate of 50% of mature plants every 10 years. Given variability due to weather and other environmental factors, we recommend that future osha harvest should be planned and adjusted after careful monitoring.