The effects of pruning on shoot production and basal increment of Acacia tortilis

Abstract

The shoot production of pruned, felled and undamaged Acacia tortilis trees on an old land site in the northern Transvaal was compared over two growing seasons. Trees were tolerant of damage and continued to increase in size when all current season’s shoots were removed. Basal increment of treated pruned trees was less than controls. Shoot production, relative to basal area, increased after winter pruning and decreased after summer pruning. Shoot production and basal increment were positively correlated with rainfall and indicators of soil moisture. Replacement shoots of pruned trees had a higher moisture content and leaf mass in the dry season and were more thorny than shoots of undamaged trees.