The study estimated the physical and monetary value of forest biomass and the existing stored carbon (C), and the rate of C sequestration by vegetation in Ayer Hitam Forest Reserve (AHFR), Puchong, Selangor. The estimates used direct measurement - based method by a sample survey of AHFR where both above-ground and below-ground C pools were considered. Allometric biomass equations were applied to estimate individual tree biomass per hectare. The total amount of forest biomass - above-ground and below-ground - ranged from 209 to 222 t ha^-1 and the corresponding quantity of C stock ranged from 104 to 111 t ha-1. The rate of change of the C stocks was between 4 and 6.5 t ha^-1 yr^-1. Such rate of C sequestration was relatively high, comparable with sequestration rate of fastgrowing Mahagony (sweitenia macrophylla) plantation. Using a weighted average price of carbon ranging from USD4.00 t^-1 to USD50 t^-1, the estimates of the value of C stock ranged from RM1,654 ha^-1 to RM20,800 ha^-1. The corresponding value of AHFR as a carbon sink thus amounted to RM2.06-25.96 million. In terms of the dynamics, the estimates of the value of C sequestration ranged from RM 0.87 million to RM 1.45 million yr^-1. The information is very useful in estimating the total economic value of AHFR and other tropical forests in future.