Abstract

Cédric Ilunga1 *, Prosper Sabongo2 , Joseph Komba3 , Idriss Ayaya4 and Leopold Ndjele

One of the challenges in tree-ring analysis in the tropical regions of Africa is the lack of accessible methods for researchers working in this field. Recently, some innovative methods using Geographic Information System (GIS) tools and digital images have been developed and their use proved to be inexpensive, high accurate and efficient approach to tree-ring analysis. In this study, one of these methods (Dendro-Gis) adapted to large wood samples was tested in describing tree-rings of Milicia excelsa. The aim was to explore whether the use of GIS tools would provide additional data compared to classic methods (microscope, magnifying glass or the naked eye). For this purpose, high-resolution digital images from sanded crosssection stem disc of Milicia excelsa were processed using ArcMap software enhanced with other image processing softwares. The approach used made it possible to digitize ring boundaries over the entire circumference of the disc. Tree-ring analysis provided numerous data: ring width series, occurrence and location of ring anomalies (wedging rings particularly) and other geometric information stored in the geodatabases that offer possibilities of many retrospective analysis. This new knowledge is useful for future dendrochronological studies of this species in the tropical rainforests.