PEAT TEMPERATURE REGIME OF A MINNESOTA BOG AND EFFECT OF CANOPY REMOVAL

Temperatures were measured at 4 depths in a strip-cut black spruce bog [Minnesota, USA] to determine the effect of forest canopy removal. Canopy removal had no effect upon temperature in the top 1 m of the bog. Changes in vegetation or microbial activity due to temperature changes would not be anticipated following canopy removal. Radiant energy exchange probably has little or no direct influence upon peat temperatures in a vegetated bog. Surface peat temperatures were closely correlated with air temperatures, with temperatures at a depth of 2 m lagging several months behind. Temperature differences between forested and cleared strips were observed at 2 m depth, but these differences may be attributed to differences in the distance to the underlying mineral soil and to water exchange between the bog and the regional groundwater system. Outlet stream temperatures indicated that streamflow originates from the upper surface of the bog water table, the temperature of which was unaffected by forest canopy removal. Changes in the stream habitat therefore would not be expected following canopy removal.