Concerns about climate change have increased interest in developing forest management strategies to maximize carbon storage. Forest Service and University of Maine researchers evaluated total ecosystem and harvested wood carbon stocks among alternative forest management approaches (even-aged silviculture, uneven-aged silviculture, high grading, and no management) in mixed-species conifer-dominated stands in Maine. Researchers measured ecosystem carbon pools (live trees, dead wood, understory plants, and soils) and used long-term data to determine carbon stored in belowground dead roots, landfills, and harvested wood products. Though carbon storage was greatest in unmanaged stands, carbon storage differed among harvested stands. High grading (harvesting only commercially valuable trees) resulted in less carbon storage after half a century compared to either even- or uneven-aged silvicultural treatments. Findings highlight the impacts of forest management strategies on carbon storage and indicate that the type of harvest, including species and sizes of trees removed, influences the amount of carbon stored. In working northern conifer forests, sustainable forest management results in more carbon storage than exploitative cutting.