Tree biomass and soil organic carbon densities across the Sudanese woodland savannah: A regional carbon sequestration study

Mean tree biomass and soil carbon (C) densities for 39 map sheet grids (1° lat. × 1.5° long.) covering the Acacia woodland savannah region of Sudan (10–16° N; 21–36° E) are presented. Data from the National Forest Inventory of Sudan, Harmonized World Soil Database and FAO Local Climate Estimator were used to calculate C densities, mean annual precipitation (MAP) and mean annual temperature (MAT). Above-ground biomass C and soil organic carbon (SOC, 1 m) densities averaged 112 and 5453 g C m−2, respectively. Below-ground biomass C densities, estimated using root shoot ratios, averaged 33 g C m−2. Biomass C densities and MAP increased southwards across the region while SOC densities were lowest in the centre of the region and increased westwards and eastwards. Both above-ground biomass C and SOC densities were significantly (p < 0.05) correlated with MAP (rs = 0.84 and rs = 0.34, respectively) but showed non-significant correlations with MAT (rs = −0.22 and rs = 0.24, respectively). SOC densities were significantly correlated with biomass C densities (rs = 0.34). The results indicated substantial under stocking of trees and depletion of SOC, and potential for C sequestration. Up-to-date regional and integrated soil and forest inventories are required for planning improved land-use management and restoration.

► Sudanese woodland savannah tree biomass C and SOC (1 m) densities were estimated.
► Above-ground biomass C and SOC densities averaged 112 and 5453 g C m−2.
► SOC densities significantly correlated with above-ground biomass C densities.
► Biomass C and SOC densities significantly correlated with MAP, but not with MAT.
► C densities across the region are considerably below sequestration potential.