African Journal of Wood Science and Forestry

African Journal of Wood Science and Forestry ISSN 2375-0979 Vol. 5 (6), pp. 320-332August, 2017. © International Scholars Journals

Full Length Research Paper


Growth rings of African timber described by an approach using Gis tools: Case of Milicia excelsa

Cédric Ilunga1*, Prosper Sabongo2, Joseph Komba3, Idriss Ayaya4 and Leopold Ndjele2

1University of Kisangani, Faculty of renewable resources management, B. 2012 Kisangani, Democratic Republic of Congo,

2University of Kisangani, Faculty of Sciences, B.2012 Kisangani, Democratic Republic of Congo,

3Compagnie Forestière et de Transformation (CFT). Kisangani, Democratic Republic of Congo,

4Northeast Forestry University, College of Wildlife resources, B.150040,

5University of Kisangani, Faculty of Sciences, B.2012 Kisangani, Democratic Republic of Congo.


Accepted 24 August, 2017 


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, highly 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 cross-section 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 geo-databases that offer possibilities of many retrospective analysis. This new knowledge is useful for future dendrochronological studies of this species in the tropical rainforests. 

Keywords: Tree-ring analysis, Gis tools, digital images, Milicia excelsa, ring boundaries, wedging rings, wood description, Democratic Republic of Congo