This paper provides information on carbon stock at the habitat level in the above ground biomass (ABG), standing floor litter and soils in a 10 year-old Tectona grandis plantation following restoration of a degraded secondary forest at Obafemi Awolowo University, Ile-Ife Nigeria. Four sample plots 25 m x 25 m, two in Tectona grandis plantation and two in a nearby degraded secondary forest were studied. Soil samples were randomly collected at 0-20 cm and bulk density determined. Standing floor litter was randomly collected at five points every three months for one year, sorted into different litter components. Soil and standing floor litters carbon concentration and C stock were determined. Above ground biomass (ABG) and carbon stock were significantly (p=0.003 and p=0.0001) higher in the plantation, the order is ABG > soil > standing floor leaf litter > standing floor wood litter. Soil C stock varies from 10.47 t ha-1 in the plantation to 10.58 t ha-1 C in the forest. Above ground biomass, standing leaf and wood litter were estimated as 18.26-5.81, 0.49-0.36, 0.06-0.08 t ha-1 C, respectively (plantation to secondary forest). Reforestation after 10 years has increased C stocks by 45% in ABG in the plantations.