Playing with Asimina triloba (pawpaw): a species to consider when enhancing riparian forest buffer systems with non-timber products

A dynamic model that depicts the growth, production and possible economical gains from Asimina triloba (pawpaw), a native North American fruit, is presented. Very few horticultural data exists on this species, calibration can only be done based on estimates and on educated ecological sense. This fruit was selected to be modeled because it is native to the Eastern US and because very little is known about it. Perhaps, with the construction of a model some insight on its productivity can be obtained. The interest in this fruit stems from a deeper problem. As a consequence of the increased pollution in the Chesapeake Bay Watershed, different actions have been taken in order to control and restore its environment. Among such actions, the building and maintenance of riparian forest buffer strips has been suggested and enforced. Farmers have been adamant about implementing these new approaches because land would have to be taken out of production, thus incurring an economic loss. However, if the riparian forest buffer is enhanced with economically viable non timber species, profit could be made from the land. The authors suggest the use of pawpaws as one of many options to include in the harvestable zone of the riparian forest buffer system. Three biological scenarios and four economical scenarios were tested in the model. We observed that unless pawpaw harvesting associated wages are cut, or subsidies for the economical exploitation of pawpaw riparian buffer strips are generous, the financial viability of such buffer strips using pawpaw as the harvestable species is reduced. In one of such scenarios, given a 5 ha pawpaw riparian buffer strip, where the farmer pays no wages, the pawpaw fruit is sold at $0.99 each, and the buffer is planted from new, the net present value of the buffer strip is $26 396.60.