| Abstract |
Fire is an ecological disturbance that may kill or topkill woody plants and control the biomass of woody species in disturbance prone areas, thus maintaining the co-existence of trees and grasses in savanna ecosystems. Relatively recently, savannas have been altered worldwide by a phenomenon known as bush encroachment, which is the suppression of grasses by woody species due to the increase in woody biomass. Terminalia sericea is a woody encroaching species which occurs in woodland savannas on dystrophic sandy soils; it often forms dense thickets and is considered as an encroacher on the Waterberg Plateau Park. The ability of encroaching woody species to resprout after topkill by fire, particularly in savanna ecosystems, is due to the already established and functioning carbohydrate reserves stored in the roots. From a management perspective, fire may be used as a preventative measure to combat encroachment of woody plants or less successfully as a symptom treatment. It may be possible to reduce the regrowth of woody encroaching species through the more frequent use of fire, if it is known how fast the root carbohydrate concentrations of resprouts return to pre-fire concentrations. The aim of the study was to investigate how time since last burn, in a semi-arid savanna woodland at the Waterberg Plateau Park, influences the growth of the encroaching T. sericea, in particular the replenishment of root carbohydrates subsequent to fire. The Waterberg Plateau Park is on the south-western side of the woodland to the north of the country on deep Kalahari sands. |
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