Abstract To achieve carbon neutrality in China, wood vaulting, which involves semi-permanent wood storage, should be integrated with proper thinning of plantation forests to maximize the forest carbon sink. Here, we mapped the optimal forest stand biomass carbon density and stand age in terms of forest biomass carbon sink in China during 2020‒2060, by identifying the turning points in the partial impacts of various influence factors on the satellite-based forest biomass carbon sink. Subsequently, we explored how, where, and when to perform plantation forest thinning under future climates through to 2060. When combined with wood vaulting, the optimal spatiotemporal thinning schemes could enhance national forest biomass carbon sink during 2020‒2060 by 32.2% and 32.8% compared to natural conditions under the high and medium emission scenarios, without compromising the forest live biomass carbon stock. Our study outlines a new pathway towards carbon neutrality in China, offering insights for global climate change mitigation.