Changes in microclimate after stand conversion in two northern hardwood stands

Changes in air temperature, soil temperature, and soil moisture were monitored for 5 years in two northern hardwood stands after whole-tree harvesting and conversion to red pine ( Pinus resinosa Ait.) plantations. Soil temperatures at a depth of 5 cm and maximum air temperatures 2 m above the soil surface were increased 5–25% after stand conversion. Soil moisture content at a depth of 5 cm was increased by 10–20% in one stand but not in the other. Differences in stand, soil, and topographical characteristics between the two stands did not have any apparent effect on the magnitude of air or soil temperature changes after stand conversion. However, higher initial stand density and soil water holding capacity appeared to be related to increased soil moisture content at one of the sites. The increased soil temperatures after conversion were not only a result of the removal of the northern hardwood canopy but also the removal and redistribution of the forest floor caused by whole-tree harvesting. Five years after stand conversion air temperature, soil temperature, and soil moisture showed no evidence of recovering from initial post-harvest levels.