Root suckering dynamics of Dichrostachys cinerea

Root suckering is the phenomenon whereby a plant is able to produce new stems
from buds on its roots. Dichrostachys cinerea is a widely occurring species well
known for its ability to encroach in disturbed areas. Reports of its ability to spread
vegetatively by means of root suckering prompted this investigation into its rooting
morphology, as an attempt to begin to understand the regeneration dynamics of D.
cinerea in savanna systems. It does not appear to conform to the savanna plant life
history strategy proposed by the Demographic Bottleneck Model, in that it thrives
within the fire trap. Twelve individuals were excavated in the mesic savanna region
surrounding Pretoriuskop in the Kruger National Park, South Africa. Six of these
individuals were found to be linked root suckers, while no root connection was found
in the other six individuals. None of the root suckering individuals had a tap root,
suggesting that a lateral spreading network of roots without a tap root may be a
feature of D. cinerea where it is root suckering. Of the individuals where no root
connection was observed, three individuals had a tap root and three did not. The stem
basal area was found to be positively correlated to bole area (r2 = 0.817), and also to
root area (r2 = 0.5301), suggesting a consistent pattern of resource allocation
throughout the lifespan of an individual. The relationship between above ground and
below ground biomass as well as observations of the nature of root suckering is
hoped to provide a useful starting point for future studies. The observation of root
suckering in D. cinerea is important for future management strategies, and also
requires the definition of a new life history functional group for savanna systems.