Short‐term burning treatments and ecological interactions in the herb layer of false thornveld of the eastern province

Controlling bush encroachment with fire in the savanna areas of South Africa

“…Preliminary results on the effect of season of burning in the arid savannas of the Eastern Cape (Trollope, 1979 a) and supported by similar results from the moist savannas in Natal (Tainton, Groves & Nash, 1977) indicate that burning can be applied before the first spring rains when an intense fire is assured, without haying undue deleterious effects on the grass sward. Nevertheless the fire should be applied as close to the commencement of the growing season as possible so as to minimise the period of excessive soil exposure and therefore potential soil erosion.…”

“…While recognising the merits of this principle the author is of the opinion that in the absence of published botanically evidence to support this hypothesis, it is very difficult to assess the effect of burning on the botanical composition of the grass sward under a system of controlled selective grazing. Research results (Robinson, Gibbs Russell, Trollope, Downing, 1979) and field experience gained at the University of Fort Hare in the Eastern Cape indicate that the efficiency of controlled selective grazing in improving the botanical composition of the grass sward depends upon the successional status of the desirable and undesirable grass species. In situations where the undesirable grass species is lower in the grassland succession than the desirable species, controlled selective grazing is effective in reducing the abundance of the undesirable species.…”

“…Research and experience gained at the University of Fort Hare indicates that a sufficiently intense fire will be obtained when the grass fuel load is 5* 3,000 kg/ha fuel moisture == 40% (fully cured), air temperature !> 25°C, relative humidity ^ 30% and soil moisture preferably less than field capacity. Wind speed is apparently not important under controlled burning conditions (0-20 km/ha) because the fire generates its own air movement through convection and is therefore largely independent of the overall atmospheric wind conditions (Trollope, 1979 a). The fire intensity from such a fire will be normally effective in destroying the stems and branches of trees and shrubs up to a height of approximately 2 m.…”

Short-Term Responses of Southern African Semi-Arid Rangelands to Fire: A Review of Impact on Plants

“…The phenomena for the aforementioned situation were already discussed under impact of fire on basal cover, where burning of bigger tufts generate a higher temperature. By contrast, in the higher rainfall False Thornveld of the Eastern Cape in South Africa (AE500 mm rainfall), for example, frequent burning favors T. triandra and also has a negative effect on the abundance of C. pospischilii (Robinson et al, 1979;Snyman et al, 2013). This parallels the results for the Tall Grassveld of KwaZulu-Natal (AE500 mm rainfall) in South Africa (Everson, 1999), where Tristachya leucothrix Nees, C. excavatus Hochst and C. validus Stapf ex Burtt Davy become dormant when burning is infrequent, provided other forms of defoliation are not imposed.…”

“…One of the most important reasons for this original decline in production due to fire in specific semi-arid areas could be the decrease in plant density and basal cover (Robinson et al, 1979;Snyman, 2005b). Depending on the climatic conditions, aboveground phytomass production of burned rangeland can normally take at least two growing seasons for full recovery (Table 1).…”