Effect of clearcutting of boreal spruce forest on air and soil temperature conditions.

Air and soil temperatures were measured in 1974-85 in 3 clear felled areas and 3 neighbouring forest stands dominated by Norway spruce (Picea abies) in N. Finland. Daily temperatures were measured with thermograph plotters and maximum and minimum thermometers in meteorological screens (2 m above the ground), and a Grant device at 10 cm above the ground and at 5, 50 and 100 cm below ground level. Clear felling had no significant influence on air temperature at 2 m above the ground. The daily air temperature maxima at 10 cm were greater in the clear fell area than in the forest; the daily temperature minima at 10 cm were less in the clear fell area. Night frosts were more common in the clear fell area. Daily soil temperatures at 5 cm depth were 2-3 degrees C greater in the clear fell area than in the forest; temperatures at 50 cm and 100 cm depth were 3-5 degrees C greater. A sparse sapling stand developed from plantings and natural regeneration. Consequently, the differences between the clear fell area and the forest did not diminish during the 12 years following clear felling