Allometric relationships and peak-season community biomass stocks of native shrubs in Senegal's Peanut Basin

Allometric equations and community biomass stocks are presented for Guiera senegalensis J.F. Gmel ( Gs) and Piliostigma reticulatum (DC.) Hochst ( Pr) – two native shrub species in the Sahel. These shrubs are of interest because they dominate semi-arid sub-Sahalien Africa but have been largely overlooked as a key biomass component and regulator of ecosystem composition and function in this landscape. In Year 1, best predictors of aboveground biomass were height and number of stems ( Gs) and crown diameter ( Pr); and for belowground biomass were height and basal diameter ( Gs) and basal diameter ( Pr). In Year 2, height and crown diameter were the best predictors of aboveground biomass ( R 2 = 0.90 for Gs and 0.87 for Pr), whereas basal diameter and number of stems ( Gs) and basal diameter ( Pr) were best predictors of belowground biomass. Peak-season biomass estimates ranged from 0.44 to 4.58 ton ha −1 (mean = 2.38 ton ha −1) in the Gs sites and from 0.33 to 7.38 ton ha −1 (mean = 3.71 ton ha −1) in the Pr communities. Both species exhibited unusually large root:shoot ratios (4.5:1 for Gs and 10.2:1 for Pr). Although models differ between years, allometric relationships provide reasonable biomass estimates for Gs and Pr.