A TECHNIQUE TO RECONSTRUCT RIVER DISCHARGE HISTORY FROM TREE-RINGS1

ABSTRACT: Cores were obtained from several tree species located both on a river floodplain and a nearby terrace. A ratio of annual tree growth on floodplains to terrace growth was developed and shown to be related to the annual river discharge. Growth ratios from the time prior to written records can therefore be used to reconstruct river discharge and infer past unrecorded flood frequency. Oak and basswood ratios yielded the best models for discharge reconstruction, whereas those of elm and birch were less useful. This method permits reconstruction of river discharge from an assemblage of growth cores obtained within a relatively small area.