The relationship between ring width measures and precipitation for Widdringtonia cedarbergensis

Abstract

Within South Africa there is a growing need for a high resolution proxy rainfall record that goes beyond the historic record. As a contribution to meeting this need the relationship between rainfall and Widdringtonia cedarbergensis Marsh, ring width indices is re-evaluated. As opposed to the various Podocarpus sp. it is possible to develop an annual ring width chronology for Widdringtonia cedarbergensis. In the present study, two more chronologies are added to the single chronology already available for this species. The development of these well dated ring width index chronologies is hampered by a lack of an abrupt termination of late wood growth in many of the trees utilised for this study. Despite this limitation the results show that with a large enough sample size it is possible to develop well-dated ring width indices from Widdringtonia cedarbergensis. Correlations between ring width indices and rainfall are not sufficiently high to reconstruct rainfall through time.