THE DEFINITION OF SEASONAL GROWTH ZONES IN SOME AFRICAN ACACIA SPECIES - A REVIEW

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 a rid areas, Acacia. The ring boundaries are marked by fine marginal par enchyma containing small crystals of Ca-oxalate. Rings are usually ann ual and produced in the rainy season. Ring width is related to precipi tation and/or minimum temperature. Rooting characteristics of the vari ous species studied influence the type of relationship found.