Evaluation of Agroforestry Carbon Storage Status and Potential in Irrigated Plains of Pakistan

The Kyoto Protocol includes agroforestry practices as a suggested approach for mitigating global atmospheric CO2. Agroforestry systems are a desirable option for mitigating atmospheric CO2, as they provide numerous secondary benefits, including food, fodder, fuel, increased farm income, biodiversity maintenance, and soil conservation. This research was planned to assess the current carbon storage status and future potential of agroforestry systems in Pakistan through a nondestructive approach (allometric equations) in 14 subdivisions (tehsils) of three selected districts located in the irrigated plains of Punjab, Pakistan. A total of 1750 plots of 0.405 ha each were selected in a randomized, unbiased sampling to estimate the total number of trees, tree species diversity, diameters at breast height (DBHs), and tree heights. Soil carbon was also measured at 0-30 cm using the Walkley-Black method in a subset of plots. It was found that the current number of trees in farms in the study area varied from 18 to 51 trees/ha, which can be increased to 42-83 trees/ha if all the farmers plant the maximum permissible number of trees along with their crops. The estimated total tree carbon stock ranged from 0.0003 to 8.79 Mgha(-1), with the smallest mean value of 0.39 Mgha(-1) for tehsil Faisalabad, and the largest mean value of 1.41 Mgha(-1) for tehsil Chiniot. The whole study area had an estimated woody vegetation carbon stock of 950,470 Mg and a soil carbon stock of 22,743,008 Mg. If farmers in the study area all increased tree stocking to their average maximum desired stocking, the total tree carbon stock would more than double to 2,497,261 Mg. These results highlight both the current and potential carbon sequestration potential of agroforestry in Pakistan and can be further used in devising strategies for implementing tree planting programs on agricultural lands and designing future carbon sequestration projects in Pakistan.