Effect of Clearcutting of Boreal Spruce Forest on Air and Soil Temperature Conditions

Helsinki

1991

42 S.

51 Lit. Ang.

Bandaufführung

2623

36997

The present paper deals with the effects of clearcutting on soil and air temperature and the development of temperature conditions during the 12 growing seasons following clearcutting. The temperature measurements were carried out by means of thermographs, Grant measuring devices and minimum and maximum glass thermometers. Clearcutting had no significant influence on temperatures measured at 2m above the ground in a meteorological screen and no changes occurred in them during the period studied, while on the ground level and in the adjacent layer of air the daily maxima increased and the daily minima decreased as compared with uncut forest. The greatest difference was over 10 Grad C between the maximum temperatures at 10cm and almost 8 Grad C between the minimum temperatures. Night frosts were considerably more common at 10cm above the ground in the clearcut area than in uncut forests. Temperature differences were smaller in the soil than close to ground level. Day temperatures were 2-3 Grad C higher in the clearcut area than in uncut forests, and differences between night temperatures at this depth were even smaller. Correspondingly, temperatures were 3-5 Grad C higher at depths of 50cm and 100cm in the clearcut area during the whole measurement period. The differences between the temperatures in the clearcut area and uncut forests did not diminish to any significant extent during the 12 years despite the stocking of the former area with seedlings.