This paper reviews and summarizes the results of investigations at the Oxford Forestry Institute on the occurrence of seasonal growth rings in the wood of one of Africa's most widely distributed genera in the arid areas, Acacia. The ring boundaries are marked by fine marginal parenchyma containing small crystals of Ca-oxalate, Rings are usually annual and produced in the rainy season. Ring width is related to precipitation and/or minimum temperature. Rooting characteristics of the various species studied influence the type of relationship found.
In: IAWA Bulletin (new series). 16. (4). pp. 353-359.