The coppicing ability of Acacia erubescens and Combretum apiculatum subsp. apiculatum in response to cutting

Abstract

The investigation was conducted in the Limpopo Province of South Africa. Twenty single stemmed trees of both Acacia erubescens and Combretum apiculatum subsp. apiculatum were randomly selected and five trees of each species were cut at heights of 5cm, 15cm, 30cm and 45cm above ground level. At the end of the following five growing seasons leaf dry mass estimates were calculated using the BECVOL-model. Both species coppiced vigorously, but C. apiculatum achieved a higher leaf dry mass production (mean of 875g tree-1) in comparison to A. erubescens (mean of 608g tree-1). In the case of A. erubescens the leaf dry mass production at the end of the 5-year trial period varied from a minimum of 460g tree-1 at a cutting height of 5cm to a maximum of 768g tree-1 at a cutting height of 15cm. In the case of C. apiculatum it varied from a minimum of 668g tree-1 at a cutting height of 15cm to a maximum of 1 074g tree-1 at a cutting height of 30cm. The effect of the cutting height on the subsequent height of the coppice growth differed between the two species. In the case of A. erubescens the total height of the coppice growth differed significantly between plants that were cut at different heights, but not in the case of C. apiculatum. The cutting height had no significant effect on the leaf dry mass production of both species. Despite the lack of statistically significant differences, the leaf dry mass production tended to be higher with an increase in cutting height. Depending on the cutting height, the A. erubescens trees will regrow to their original leaf biomass (average of 1 429.7g tree-1) within 5.9 to 9.4 years (seasons) and the C. apiculatum trees (average of 1 748.9g tree-1) within 7.1 to 15.8 years (seasons).