Quantification by allometric equations of carbon sequestered by Tectona grandis in different agroforestry systems

Non destructive methods for quantification of carbon sequestration in tropical trees are inadequately developed. We described a standardized method for estimating carbon stock in teak (Tectona grandis Linn. F.). We developed linear allometric equations using girth at breast height (GBH), height and age to quantify above ground biomass (AGB). We used AGB to estimate carbon stock for teak trees of different age groups (1.5, 3.5, 7.5, 13.5, 18.5 and 23.5 years). The regression equation with GBH, y = 3.174x ? 21.27, r ²=0.898 (p <0.01), was found precise and convenient due to the difficulty in determination of height and age in dense natural forests of teak. The equation was evaluated in teak agroforestry systems that included Triticum aestivum (wheat), Cicer arietinum (gram), Withania somnifera (ashwagandha), Avena fatua (wild oat) and Hordeum vulgare (barley) as agricultural crops established at Tropical Forest Research Institute, Jabalpur, M.P. (India). The annual carbon stock gain in teak in different agroforestry systems was in the order: teak-barley (60.47%) > teak-wheat (56.92%) > teak-wild oat (54.94%) > teak-gram (37.15%) > teak-ashwagandha (11.86%). The results from GBH-based regression equations provided satisfactory estimates of carbon stock in tropical trees.