The research experiment was carried out to evaluate the effects of various nitrogen sources combination on biochemical indices in Swietenia macrophylla and Swietenia mahogany at Forest College and Research Institute, Tamil Nadu Agricultural University, Mettupalayam. The study consists of ten different types of nitrogen fertiliser combinations (Organic and inorganic sources) includes control (without any fertilisers application) to compare the treatment effect in two tree crops. Research experiment was laid out in Randomized Block Design (RBD) with three replications. Swietenia macrophylla T2 (Urea + sheep manure) combined application shows statistically significant differences in bio chemical indices (Chlorophyll a and b) after the fertiliser application during the research experiment. In Swietenia mahogany T2 (Urea alone) shows the statistically significant difference in biochemical indices (Chlorophyll a and b) during the experimental research period. In both tree, crops did not explain any statistically significant differences in Carotenoids content due to fertiliser application at the time of research experiment.