Estimation of phenotypic and genotypic correlation between various traits provides necessary information in breeding program, when selection is based on two or more characters. The intensity and trend of association among characters may be estimated by genetic coefficients of correlations and genotypic and phenotypic coefficient of correlation depending on the type of materials studied. The knowledge of genetic inter-relationship between characters is also of theoretical and practical interest because a genotypic correlation may drive genetic linkage or from developmental induced relationships between components that are only indirectly the consequences of gene action. Terminalia arjuna is a medium to large sized fast growing versatile tree popularly known as Arjun. It has immense economic potential in various industries viz., pharmaceutical, timber, paper, soap, tannin, dye, match, food, fodder and fuel. Thirty candidate plus trees (CPTs) of T. arjuna were selected as seed source from 30 different provinces of Uttar Pradesh for the study of correlation study morphological & biomass traits. After 12 months of growth under nursery condition, data were collected and analyze for association studies. Present study concludes that magnitudes of phenotypic correlation coefficients were lower compare to corresponding genotypic values. A strong positive and highly significant phenotypic correlation with collar diameter, bark content, fresh shoot weight, dry shoot weight, fresh root weight, dry root weight and total biomass of seedling were exhibited. Therefore, these characters may be given proper emphasis during selection and breeding program of Arjun tree species where the amount of leaf, bark and biomass production is of immense importance.