Forests have been recognized to have positive impacts on both physical and mental health. While previous studies demonstrate the positive health effects of residential greenness, large spatiotemporal studies on forest cover change and human mortality are lacking. With continuing deforestation trends and various reforestation efforts, this study first aims to quantify forest cover change and associated mortality in the elderly population in China over 15-year period. Second, we aim to assess whether the effect of reforestation counteracts deforestation, or that these two effects can simultaneously affect health. Third, we aim to determine the spatial scale of the effect of forest cover change. Here we used a longitudinal open cohort of 31,038 participants totaling 111,607 person-years of follow up across China. We applied Cox proportional hazard models to assess the effect of forest coverage in four spatial scales, adjusted for potential confounders.
Results/Conclusions
We found a protective effect of forest gain in all spatial scales, while forest loss increased mortality only in a 100km radius around the residence. The effect of both forest gain and loss became more prominent as the spatial scale expanded. With 1% of forest gain in 100km-radius, mortality reduced by 6.5%. While urban residents were more sensitive to the forest change closer to their residences (<10km), rural populations showed a strong association between forest cover change and mortality in the 100km radius. Our research provides epidemiologic evidence of health co-benefits and a nature-based solution through forest conservation and restoration, which is key to combat biodiversity loss and climate change.