Short-term temperature response in forest floor and soil to ice storm disturbance in a northern hardwood forest

Abstract

Significant changes in the temperature of forest floor and soil of the Hubbard Brook Experimental Forest occurred as a result of canopy damage caused by a major ice storm in Jan. 1998. The summertime patterns among open, brush-pile, and reference sites were clear and repeatable: (1) air temperatures at all sites peaked at about the same time each day although the average open-site values were 1 to 4°C higher; (2) the pattern at 2- and 15-cm [0.8- and 5.9-in.] depths was similar to air; (3) the open value was 5 to 9 and 6 to 10°C higher than that in the reference site and brush-pile sites, respectively; (4) there was a lag of ∼0.3 hours for daily peak temperatures between the air and 2-cm depth, and ∼3.3 hours between the daily maximum temperature at 2- and 15-cm depth for the open sites; (5) the open site temperature at both 2- and 15-cm depth was ∼2°C higher than reference and brush-pile temperatures (average daily temperature for the brush-pile site rose to be roughly equal to that in the open site in Aug. 1999 and Aug. 2000, while the reference site remained about 2°C lower); (6) small, but not statistically significant, changes were observed at the 50-cm [19.7-in.] depth where the open site was ∼1°C higher than the brush-pile or reference sites; and (7) regrowth of vegetation in the canopy gaps during the first 3 years reduced forest floor temperatures to or below the temperature at the 2-cm depth in the reference site. These results have potential ecological importance to the northern hardwood forest ecosystem.