Does the description of a root system matter for sustainable use and conservation? A case study in Burkina Faso

Sarcocephalus latifolius (Sm.) E. A. Bruce is one of the most useful medicinal plants in many African countries. The root being the part generally used for this purpose. In the context of land degradation and overexploitation of biological resources in many parts of Burkina Faso, a good description of the root system is necessary to better plan for sustainable use and conservation. We aim to answer the following: i) What is the root system architecture of S. latifolius in the Sudanian zone of Burkina Faso? ii) What amount of root biomass is produced by the species? iii) Can we use a semi-destructive method to establish a model for root biomass prediction?

Forty plants were randomly selected and their dendrometric parameters were measured. For each sampled tree, the quarter of the roots were harvested and weighed. Results show the species has a superficial lateral root system. The roots grow towards other species, but do not form anatomical links with roots of other species. An allometric equation for root biomass prediction was developed through a multiple linear model. As a practical use of the present study, we propose, that people using this plant to treat illness should search for roots at approximately 10m between the trunk of mature individuals of S. latifolius and another species, instead of using roots near the trunk. Thus, only the ends of roots would be cut. Using this method could limit tree mortalities due to root harvesting and contribute to the preservation of this important species.