Effects of season of burn on shrub survival, regeneration and structure in the Natal Drakensberg

Abstract

Abstract Four shrub species which tend to invade unburnt grassland were studied in field‐burning trials at Cathedral Peak in the Natal Drakensberg. Results showed that neither hot winter burns, nor cool summer burns, affected the ability of Buddleia salviifolia, Leucosidea sericea, Widdringtonia nodiflora or Philippia evansii to survive fire. The first three species resprouted following damage to their shoot systems. The winter burns damaged more canopy, resulting in proportionally more basal resprouting and higher net gains in new stems. Summer burns, on the other hand, resulted in proportionally more defoliated stems developing aerial resprouts. P. evansii, in contrast, was sensitive to fire and the species regenerated from seed, with larger recruitment of seedlings following winter than summer burns. Season of burn was shown to be important insofar as it affected shrub structure and the nature and amount of regeneration. Management objectives would therefore influence the way in which fire is used in these shrublands.