The cycling of mercury (Hg) within forested ecosystems is impacted by atmospheric deposition, sequestration in soils and vegetation, surface emissions, and mobilization in runoff. Mercury cycling can be impacted by forestry operations where clear-cut logging most of the vegetation cover by impacting several of the key flux processes, as well as foodweb dynamics and bioaccumulation.  This paper measured surface-air Hg fluxes from catchments in the Pacific Northwest, USA to determine if there is a difference between forested and logged catchments.  These measurements were conducted as part of a larger project on the impact of forestry operations on Hg cycling which include measurements of water fluxes as well as impacts on biota (published separately).   Surface-air Hg fluxes were measured using a commonly applied dynamic flux chamber (DFC) method that incorporated diel and seasonal variability in elemental Hg (Hg⁰) fluxes at multiple forested and harvested catchments.  The results showed that the forested ecosystem had depositional Hg⁰ fluxes throughout most of the year (annual mean: -0.26 ng/m²/h).  In contrast, the harvested catchments showed mostly emission of Hg⁰ (annual mean: 0.63 ng/m²/h).   Differences in solar radiation reaching the soil was the primary driver resulting in a shift from net deposition to emission in harvested catchments.  The surface-air Hg fluxes were larger than the fluxes to water and accounted for 97% of the differences in Hg sequestered in forested versus harvested catchments.