The study site was established at a cool temperate bog, Bibai Mire, in Hokkaido, northern Japan. The Bibai Mire is one of the remaining mires of the Ishikari Mire, which originally had an area of 55,000 ha but decreased to 119 ha after agricultural development. The Bibai Mire was a 22 ha conserved mire, but only 2 ha was preserved with the original bog vegetation intact. The site within the flux footprint was characterized as the original bog, where graminoids (Moliniopsis japonica), sedges (e.g., Carex omiana, Carex middendorffii, Rhynchospora alba, Rhynchospora fauriei, and Eriophorum vaginatum), and sparse woody plants (Vaccinium oxycoccos, Myrica gale, and Ilex crenata) were distributed among Sphagnum mosses (Sphagnum papillosum). Since the site was on a well-developed bog, the vegetation was relatively homogeneous within the flux footprint. The thickness of peat was approximately 4 to 5 m, which began to accumulate on the alluvial plain approximately 2000 years ago. The turbulent fluxes of sensible heat, latent heat, CO2, and CH4 were measured using the eddy covariance system installed at 2.3 m above the ground using pipe scaffolding.
