Toward a Biophysical Evaluation of Forest Site Potential

Abstract

Soil characteristics, soil moisture, radiation exchange, and temperature regimes on adjacent 20 percent north- and south-facing slopes suggest that, in areas of high summer precipitation, marked differences in growth are not associated with soil moisture differences. During midday periods on south-facing slopes, it appears that 1) super-optimum temperatures for net assimilation occur frequently in forest canopies, 2) lower soil temperatures limit the absorption of available water, and 3) higher canopy temperatures increase the transpiration demand, create leaf water deficits earlier in the day, and magnify the midday depression of net assimilation. Forest Sci. 20: 145-154.