Forest and its bi-product (often called as biomass) are the essential part of environment. Forest is directly or indirectly serving human being from the very beginning. Three forest ranges of Gorakhpur district of Uttar Pradesh namely Banki, Tilkonia and Pharenda are the reserved forest which have Sal (Shorea Robusta) and Sagaun (Tectona Grandis) as the dominant species. The biomasses generated from the three forest range are mainly dry leaves and twigs which are generally used as litter. The biomass production of three forest ranges are 2782.91 Kt. The trees are mostly mature in which the results state that the Sal plantation forest are with less Above Ground Biomass. It is revealed that plantation forest has large tree population with less DBH class. The plantation forest has greater carbon stock as well as great carbon sequestration potential than any other forest.