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(Figure 36) and greater stem diameter growth (Figure 66) on fresh soil than stored <br />soil, but terminal leader growth appeared similar on both soii types (Figure 5B). <br />Natural root sprouts had no lateral branches. Leaves also appeared to be larger on <br />these trees (data not shown). Nevertheless, these trees apparently experienced <br />somewhat greater pre-dawn water stress in July and September than trees in the <br />irrigated treatments, including the irrigated controls with no water added (Figures 9, <br />10), June pre-dawn and afternoon water stress levels (Figures 8, 11) appeared to be <br />similar for all treatments. The data suggest that pre-dawn water stress levels as high <br />as 14 bars, and afternoon water stress levels as high as 20-25 bars, were not of <br />sufficiently high levels to cause enough stress to reduce survival of these trees. <br />Moisture stress appeared to be less with transplanted sprouts in the irrigation <br />experiment, including the un-irrigated controls, than with root sprouts, potted plants, <br />or natural sprouts in July and September (Figures 96 - 106). It is interesting to note <br />that leaves appeared smaller and terminal growth appeared less on these apparent <br />less-stressed transplanted trees (Figures 3 and 4), suggesting that growth of root <br />sprouts, potted plants, and natural sprouts was not limited by the apparent higher <br />moisture stress levels they experienced. Maximum leaf water potentials at mid- <br />afternoon (Figure 11 A, 11 B) found stress levels of about 25 bars or less, levels that <br />appeared unrelated to treatment, or to growth and survival. <br />The growth data suggest that fresh soil could have provided additional nutrients or <br />other benefits, perhaps mycorhizae, for tree growth. Weed growth appeared greater <br />on fresh soil than stored soil (data not shown). Since we weeded around all <br />monitored trees for this experiment, weeds were not a competitor for the aspen in <br />this study. <br />Fencing: <br />Fencing is necessary to obtain an adequate stand of aspen, regardless of the <br />sources of the trees. The unfenced Yoast site had severe damage from ungulates <br />(Table 1), including breakage of stems, browsing, and rubbing damage. Most trees <br />8 <br />