Rural healthcare facilities play a vital role in community well-being but are often overlooked in sustainability discussions. While urban hospitals integrate green infrastructure to mitigate carbon emissions, rural healthcare landscapes rely heavily on natural vegetation, particularly mature trees, for environmental benefits. This study investigates the carbon sequestration potential of mature trees within the landscape of Hospital Gerik, a rural public healthcare facility in northern Perak, Malaysia. The research adopts a quantitative methodology, using tree biomass analysis to calculate the annual carbon dioxide (CO2) sequestration of all inventoried trees within the hospital compound. Results reveal a total carbon sequestration value of 172.66 tonnes CO2 per year with an overwhelming 92% contribution from mature trees, despite their lower population compared to younger trees. These findings highlight the ecological value of preserving mature trees, which play a imbalanced role in carbon sequestration and climate mitigation. The study reinforces the critical importance of incorporating mature tree preservation into landscape management policies for healthcare environments. It also calls for the development of national guidelines that recognize the environmental functions of natural vegetation in institutional settings, especially in low density or rural areas. Promoting such low carbon, nature-based strategies aligns with Malaysia’s broader climate goals under the 12th Malaysia Plan and the National Low Carbon Cities Framework.