Performance de croissance de quelques espèces ligneuses sous l’effet du pâturage dans la savane soudanienne

Performance de croissance ligneuse sous pâturage

Abstract

The degradation of forest resources is a major concernin sub-Saharan Africa and especially in Burkina Faso. Restoration initiatives are being undertaken, through the enrichment of areas losing vegetation cover. The aim of this study was to assess the growth performance of woody species planted in a Sudanian savannah subject to grazing. The methodology consisted of assessing survival rate and measuring dendrometric parameters such as crown diameter and height of seedlings of 10 ligneous species planted 5 years ago. These dendrometric measurements were used to assess the relative growth rates in diameter (DGR) and height (HGR). The results showed that survival rates varied from one species to another, with the highest rate recorded in the grazed area (32.25%). The species Anogeissus leiocarpa (DC.) Guill. & Perr., Sclerocarya birrea (A. Rich.) Hochst. and Combretum nigricans Lepr. ex Guill. & Perr. showed the best survival rates in the grazed and ungrazed areas. The results also showed that growth rate of the majority of species declined, with the exception of A. leiocarpa, which had positive values for both DGR (0.32 ±1.6 mm/year) and HGR (0.01 ±1.6 mm/year). The effect of grazing was also significant for the HGR, which decreased but less in the grazed area (-1.32 ±1.8 mm/year) than in the ungrazed area (-1.83 ±1.7 mm/year). The study identified some species of interest for restoration initiatives in environments similar to our study site. Furthermore, the presence of grazing, when moderate, could have a beneficial effect on the development of ligneous plants, probably through its interaction with other degradation factors.