CO₂ mediated enhanced oil recovery (CO₂-EOR) may lead to methods of CO₂ reduction in the atmosphere through carbon capture and storage (CCS); therefore, monitoring and verification methods are needed to ensure that CO₂-EOR and CCS activities are environmentally safe and effective. This study explored vegetation growth rate to determine potential ecological effects of emissions from CO₂-EOR activities. Plant relative growth rates (RGR) from plots within an oilfield and reference areas, before and after CO₂ breakthrough were used to assess CO₂-EOR activities impact surrounding vegetation. The trend for both areas was the decrease in RGR ratio during the study time; however, the decrease in RGR ratio was significantly less in the oilfield area compared to the reference area overall and by subcategories of pine, tree and shrub. Based on data from plant plots, RGR decreased in the reference and oilfield areas except one plot, which increased in RGR. Within the oilfield and reference areas, several species decreased significantly in RGR, but American olive increased in RGR. Vegetation monitoring could provide parameters related to the modeling potential effects of emissions on local ecosystems (species, groups and community) and serve as a necessary component to the monitoring and verification of CO₂-EOR and CCS projects. The challenge and limitations of vegetation monitoring were also discussed. Full article