Acta Scientiarum Polonorum

Abstract: The present study concerns the effect of weather conditions and of the biometrical characteristics of forest on the course and dynamics of changes in air temperature in the vertical profile of forest. The aim of research was to compare the values and patterns of air temperature in a spruce stand and on a mountain meadow. The investigations were conducted in a 30-year-old spruce stand situated in the area of the Experimental Forest Station in Krynica. The stand grows at an altitude of 800 m on a gentle slope of eastern exposure, on the mountain forest site, in the conditions of a temperate cool climate. The meadow is located under the same geographical and climatic conditions, at a distance of 200 m from the wall of the stand. In July 1996, two 34-hour series of measurements were performed. Air temperature was measured every hour with Assmann’s psychrometer at a height of 5, 50 and 150 cm above ground level. In the spruce stand the temperature differences in the vertical profile were greater than in the open area. In the forest and on the meadow the averages of air temperature were similar. Maximum temperatures occurred near the active surface and were higher in the open area. Minimum temperatures at both measuring stations were similar. The daily amplitudes of air temperature increased towards the active surface. The vertical gradients of air temperature in the forest were always negative while on the meadow they changed according to the time of the day, wind velocity and precipitation.