This study attempts to uncover the impact of aging populations on forest growth by employing data for 158 countries during the period of 2000–2020 via GMM estimation. The baseline estimation indicates that growing aging ratio would benefit the growth of forest cover, which is credible when we conducted robustness tests by changing the measurements of forest protection, aging ratio and setting new sub-samples. Furthermore, the ratio of aging males would exert higher positive impact on forest protection than that of aging females. The trade openness, greenhouse gas emissions, and government spending would also weaken the aging ratio's positive impact on forest growth. In addition, the impact of aging ratio on forest growth is lower with right-wing governments than that with left-wing governments. Finally, aging populations would promote the individuals' environmental concern, innovation for adapting technologies in agriculture or forestry, technologies for energy generation, and technologies in plastic and rubber recycling.