| Autor: |
Monegi P; Animal Production, Agricultural Research Council, Private Bag X 02, Irene 0062, South Africa.; School of Life Sciences, University of KwaZulu-Natal, Scottsville 3209, South Africa., Mkhize NR; Animal Production, Agricultural Research Council, Private Bag X 02, Irene 0062, South Africa.; Animal and Poultry Science, School of Agriculture, Earth and Environmental Sciences, University of KwaZulu-Natal, Scottsville 3209, South Africa., Tjelele JT; Animal Production, Agricultural Research Council, Private Bag X 02, Irene 0062, South Africa., Ward D; Department of Biological Sciences, Kent State University, Cunningham Hall, Kent, OH 44242, USA., Tsvuura Z; School of Life Sciences, University of KwaZulu-Natal, Scottsville 3209, South Africa. |
| Abstrakt: |
Mechanical and chemical methods are widely used to control woody plant encroachment in many African countries. However, very little is known about the effectiveness of these control methods among woody species of different ages. We conducted a field experiment to determine the effects of different tree removal treatments (10%, 20%, 50%, 75% and 100%) and herbicide application (Picloram; 6 mL L -1 ) on the resprouting ability and vigour of 12 woody plant species. We examined 20 plots (30 m × 30 m) that were each subjected to tree removal, followed by herbicide application on half of the stems for each plot. All the tree species in this study resprouted after cutting. The applied concentration of herbicide significantly reduced the shoot production for Ehretia rigida , Vachellia robusta and Ziziphus mucronata , with a marginal effect for Dichrostachys cinerea . The diameter of stems was an important factor in determining resprouting ability, with shoot production decreasing with increasing stem diameter. However, stem diameter did not affect shoot length and diameter for all species. We found that woody plants are more likely to resprout and survive as juveniles than as adults after cutting and that herbicide only affected four of the twelve species at a concentration of 6 mL L -1 . Thus, testing the amount of Picloram needed to kill certain woody species may be of importance for land users in southern African savannas. |
