The LAI from 1948 to 2007 was simulated for jack pine and trembling aspen on the 12 soil profiles. Because LAI changes during the growing seasons, only the annual maximum value was extracted for comparison. Table 2 presents the mean and standard deviation for the maximum LAI for each soil profile. LAI differences for different soil profiles were ascribed to the influence of plant available water. Among the 12 soil profiles, the GFS had the greatest LAI value for aspen and the largest AWHC value (211.6 mm), whereas the UCS had the smallest LAI for aspen and the smallest AWHC value (12.3 mm). A positive but nonlinear relationship between the mean value of the maximum LAI and AWHC was found for each forest type (Fig. 4a).