Impact of Streamside Management Zones on Soil Temperature Changes Following Forest Harvesting.

Elevated soil temperatures may result from forest harvesting, impacting biota and altering nutrient cycles. The objective of this research was to measure soil temperature changes along transects from riparian areas to uplands following forest harvesting.  Using the paired watershed approach, three watersheds in southeastern Kentucky were harvested using different streamside management zone (SMZ) widths of 16.7 m and 33.5 m (55 ft or 110 ft) and canopy retention of 100% or 50% and an Harvested watersheds were compared to an unharvested reference watershed.  Soil temperature was measured hourly approximately 0.1 m below the soil surface at locations 7.6 m, 15.2 m, 30.5 m, and 61 m upslope from the stream.  Preliminary analyses indicate an average increase relative to the unharvested control watershed in daily mean temperature of 1.4 (7.6 m from stream) and 1.5 (15.2 m from stream) degrees C for the watershed harvested with a 16.7 m SMZ and 50% canopy removal in the SMZ in the first growing season following harvest.  Additionally, an increase in daily average temperature of 3.86 degrees C was measured 30.5 m from the stream in the two watersheds harvested with a 16.7 m SMZ during the first growing season following harvest.  Further analyses will include examinations of seasonality, changes in maximum and minimum soil temperatures, as well as in the daily range of measured temperatures.