Introduction: Butea monosperma (Lam.) Taub. is an ecologically and economically important dry-deciduous tree species widely distributed in the semi-arid Bundelkhand region. Despite its multipurpose utility, like gum production, flowers for dye, fodder, fuelwood, and medicinal compounds, there is limited scientific information on its growth variation, biomass and carbon dynamics, and nutritional composition across diameter classes and localities. Understanding silvicultural behaviour and biochemical variation is crucial for optimizing its use in agroforestry, carbon sequestration, and livelihood enhancement in the Bundelkhand region. Methods: A multistage stratified random sampling approach was adopted across 10 localities (Jhansi and Lalitpur districts), covering agroforestry systems (AFS) and naturally regenerated areas (NRA). The research employed a factorial randomized block design with the first factor as three diameter classes: D-1 (10-30cm), D-2 (30-50cm), and D-3 (>50cm), and the second factor as locality (L-1-L-5). Trees per class per site were measured for DBH, height, stem volume, above- and below-ground biomass, carbon stock, and CO2 mitigation potential. Reproductive traits (leaf and flower characteristics), gum yield, and biochemical properties of gum and flowers were analysed using standard laboratory procedures. Results: Diameter class exerted a significant influence on tree growth, biomass accumulation, and carbon sequestration. The largest diameter class (D-3) consistently recorded the highest DBH (55.56cm), stem volume (10.90m), AGB (0.72t tree(-1)), BGB (0.18t tree(-1)), Carbon stock (0.45t tree(-1)), and CO2 mitigation potential (1.67t tree(-1)) in Jhansi district. Lalitpur district also followed the same trend in terms of growth, biomass, and carbon parameters. Reproductive traits such as leaf fresh/dry weight and flower characteristics showed mostly non-significant differences among diameter classes and localities. Gum yield was significantly highest (p <= 0.05) in Jhansi and Lalitpur districts in medium-sized trees (D-2) (207.76g tree(-1), 224.6g tree(-1)), indicating locality-specific physiological responses. Biochemical composition of gum exhibited significant variation, with higher phenolic content (13.61mgg(-1)), ash (4.12%), and ascorbic acid (42.08mg 100g(-1)) in larger diameter trees. Flower biochemical traits differed significantly across sites, with Lalitpur showing greater variation in phenols (16.03mgg(-1)), ash (6.78%), antioxidants (68.90%), and carotenoids (37.14mg 100g(-1)). Overall, D-2 and D-3 trees demonstrated superior biochemical traits, reflecting higher metabolic activity. Conclusion: Butea monosperma shows substantial variation in growth performance, carbon sequestration potential, gum productivity, and biochemical composition across diameter classes and localities in Bundelkhand. Larger trees serve as major contributors to biomass and carbon storage, while gum and biochemical quality are influenced by both tree size and site conditions. The findings highlight that B. monosperma has strong ecological resilience and economic potential, supporting its wider adoption in agroforestry and livelihood-based interventions in semi-arid regions.