An image analysis system for determining densitometric and ring-width time series

Abstract

A new interactive image analysis method for determining tree-ring density and width data for dendrochronological studies is described. The method employs the Prism Image Analysis System (from Dapple Systems, Inc.) for Apple Macintosh microcomputers and uses additional FORTRAN software (program MACDRUID) developed for tree-ring applications. The principal advantages of this system are (i) interactive image analysis, which substitutes computer software for the complex scanning densitometer operations used in previous systems and (ii) high resolution, which is necessary for processing the narrow-ringed, stressed trees often sampled in dendroclimatology. Other advantages are real-time editing, ease of adjustment for angle variation of ring boundaries, and the ability to append individual frame data into homogeneous time series. Comparisons of ring-width and density data determined by this image analysis system with similar measurements derived from other methods indicate that the image analysis data are of equal precision and quality for use in dendrochronological studies. In addition to applications in the fields of dendrochronology and wood science, this image analysis method is applicable for analyzing variations in cyclical banding in other types of geological samples, such as sediment laminae (e.g., varves) and corals.