Rapidly maturing frameworks for investing in and committing to mitigation of climate change through forest management have focused almost exclusively on the benefits of carbon sequestration, without accounting for collateral changes in geophysical factors such as surface albedo. Newly available 30 m albedo retrievals derived from imagery acquired by the Landsat 8 satellite, analyzed at 273 652 field plots monitored by the United States Forest Service, suggest that large areas of the US Inter-Mountain West’s forests have a net warming impact on the planet’s surface energy balance. For the conterminous US, the impacts of albedo offset approximately half of the recognized non-soil forest carbon storage benefit. The emerging capacity to resolve albedo evolution at the scale of a large number of inventory plots also provides unprecedented empirical evidence that albedo impacts vary strongly as a function of both tree age and species group. This research highlights a correctable source of uncertainty in operational monitoring of forest-climate interactions, and it may temper expectations for forest establishment as a means of mitigating global climate change.