Estimation of carbon in the forests located in the coast of tropics is needed to support conservation and forest monitoring strategies. This study aimed at quantifying carbon stocks in the regenerating tree species of intact forest (IFS), disturbed by agriculture (ADS) and by livestock grazing sites (LDS) to understand the importance of coastal trees in carbon stocking as part of mitigating climate change impacts. Methodology: Thirty-three independent measurements of tree carbon stocks were carried out on 33 tree families found in the coastal zone of Tanzania. The vegetation was inventoried by means of a floristic survey of the woody component across intact, crop agriculture and livestock disturbed land use sites. The biomass was then estimated by employing the existing allometric equations for tropical forests. Thereafter, the above ground stored carbon was quantified on the sampled tree species found in each land uses. Results: The results showed that there were significant variations (p ≤ .05) of carbon stock values across species and land uses. The average carbon (Kg/ha) stored in the regenerated adult trees was 1200 in IFS, 600 in ADS, 400 in LDS. Saplings had 0.43 in LDS, 0.07 in ADS and 0.01 in IFS. Indeed, seedlings had the average of 0.41 in IFS, 0.22 in ADS and 0.05 in LDS. Conclusion: These findings show that crop-agriculture highly affects the regeneration potential of trees, biomass accumulation and carbon stock than livestock grazing. To restore carbon storagepotential of coastal tropical forests, crop-agriculture must be discouraged, while livestock grazing can be integrated in forest management. Indeed, further studies are required to gauge the integration levels of any anthropogenic activities, so that the natural capacity of coastal tropical forests to regenerate and stock carbon is not comprised further.