Abstract: The investigation on the forest carbon storage and fuel carbon emission in Tanjiang River basin showed that since 1990, the forests in Tanjiang River basin acted as a carbon sink, and this action was increased with time and with economic development. The net carbon uptake by the forests was 1.0579×10⁷ t in 1990 and 1.28061×10.7 t in 2002, with an annual increment of 1.856×10⁵ t, while the fuel carbon emission was 9.508×10⁵ t in 1990 and 1.8562×10⁶ t in 2002, with an annual increment of 7.0×10⁴ t. In 2003, the fuel carbon emission was up to 2.1968×10⁶ t, 3.406×10⁵ t more than that in 2002. In 2002, the energy consumption per 10⁴ yuan GDP in Tanjiang River basin was 2.21 t standard coal, higher than the average consumption (1.81 t standard coal) in the Pearl River delta. If the fuel consumption decreased to the average level, the carbon emission in Tanjiang River basin would be reduced by 3.360×10⁵ t, which was higher than the annual increment of forest net carbon uptake in the basin. From the viewpoint of net carbon uptake and emission in a basin, more attention should be paid to the relations between forest carbon sink and human activities.

Key words: Constructed wetland, Vertical flow, Downflow-upflow, Wastewater purification