The feasibility of restoring subtropical thicket using carbon markets is largely a function of its carbon sequestration potential. We measured below-ground carbon stocks and analysed soil properties in intact, degraded and old agricultural landscapes in Baviaans Spekboom Thicket - a highly degraded thicket type earmarked for restoration. Soil and root carbon stocks to a depth of 110 cm in intact thicket were 93 +/- 7 (SE) t ha(-1) and 11 +/- 2 t ha(-1), respectively. Degraded thicket had approximately one-third of the soil (31 +/- 2 t ha(-1)) and one-quarter of the root (2.7 +/- 0.3 t ha(-1)) carbon of intact thicket. Old agricultural lands had approximately half of the soil (42 +/- 4 t ha(-1)) and quarter of the root (2.6 +/- 0.3 t ha(-1)) carbon of intact thicket. Soil carbon stocks in topsoil were constrained at low concentrations of extractable K (<0.5 mmol(c) kg(-1)), Mg (<1 mmol(c) kg(-1)), Ca (<12 mmol(c) kg(-1)) and extractable P (<40 mgkg(-1)), suggesting that carbon sequestration will be strongly influenced by soil nutrient content. Restoration of Baviaans Spekboom Thicket stands to sequester 70 +/- 8 t ha(-1) of below-ground carbon - an amount rivalling sequestration potentials in degraded mesic forests. (C) 2009 Elsevier Ltd. All rights reserved.