Valuation refers to attempts to calculate monetary values for natural resources. Peters et al.’s widely cited paper (1989) on non-timber forest products suggested that the value of a tropical forest plot in Peru was more than ten times the site’s timber potential. Sheil and Wunder (2002), however, have questioned Peters’ conclusions, offering a number of questions around appropriate methodologies for valuation. For example, should actual or potential extraction values be used as the basis for valuation? Should valuation focus on values for individual users, communities, or society at large? (How) should non-economic values be taken into account? [DF]

Voucher specimen is an herbarium specimen (a pressed and dried plant) collected to serve as an example of the plant that was named. The voucher is a form of primary data and can serve to provide scientific identification of a locally named taxon. Not all herbarium specimens serve as vouchers: only those collected to verify or provide examples of locally named or used plants and that have associated cultural data are voucher specimens. [GEW]