Projecting medicinal plant trade volume and value in deciduous forests of the eastern United States
The volume, value, and distribution of NTFP trade in the United States are largely unknown. This is due to the lack of systematic and comprehensive market tracking programs. Trade measurement and mapping would allow market actors and stakeholders to improve market conditions, manage NTFP resources, and increase sustainable production of raw material. This is especially true in the heavily forested and mountainous regions of the eastern United States. This study hypothesized that the tendency to purchase medicinal NTFPs in this region can be predicted using socioeconomic and environmental variables associated with habitat and trade, and those same variables can be used to build more robust estimates of trade volume. American ginseng (Panax quinquefolius L) dealers were surveyed (n=700) because by law they must acquire a license to legally trade in this species and therefore report a business address. They also record purchase data. Similar data are not reported for other medicinal species sold to the same buyers, known colloquially as off-roots. Ginseng buyers were queried about trade activity in eleven commonly harvested and previously untracked medicinal NTFP species in 15 states. Multinomial logistic regression including socioeconomic and environmental predictors tied to business location was used to determine the probability that a respondent purchased off-roots. Significant predictors included location in a particular sub-region, population, and percentage of employment in related industries. These business-based variables were used in a two-step cluster analysis was used to group respondents and non-respondents. Modeled probabilities for off-root purchasing among respondents in each cluster were used to impute average off-root volumes for a proportion of non-respondents in the same cluster. Respondent observations and non-respondent estimations were summed and used to map off-root trade volume and value. Model functionality and estimates of the total volume, value, and spatial distribution are discussed. The total value of the species surveyed to harvesters was 4.3 million USD$. 77 percent of the trade value, and 73 percent of the trade volume were represented by two species: black cohosh (Actaea racemosa L.) and goldenseal (Hydrastis canqdensis L.).