ENVIRONMENTAL CONSEQUENCES in rocky mountain coniferous ...

and the 1 ack of this low-vegetati on response on the residues-removed/shel terwood
treatment combination (Schmidt 1980). A1 though this treatment consistently used more
water than its two burned counterparts, the differences averaged only about 6 percent
or 1.0 inches (2.5 cm) during the study period (appendix E) .
There were no substantial differences in water use between the two burned treatments
on the group selections and clearcuts where broadcast burning was reasonably
consistent. However, on the shel terwood treatment, more water was used on the intensive
utilization and burn than on the conventional utilization and burn. This may be
related to the cooler burning on the intensive uti 1 ization and burn (Artley and others
1978; Schmidt 1980). However, caution is in order because only the upper replicate
s he1 terwood data are used here--the lower rep1 i cate shel terwood was not burned.
WATER USE PATTERNS
Water use began early in the season, peaked around mid-July, and tapered off
more rapidly than it had begun. Figure 18 illustrates an average daily water use
envelope that encompasses the range of water use by all treatments evaluated in this
study. As indicated in this envelope, daily use maximums in mid-July peaked at
nearly 0.16 inches (0.4 cm) and the minimums peaked at about 0.10 inches (0.25 cm).
As expected, the uncut controls were in the upper layer of the daily use envelope and
the burned treatments on the clearcuts and group selections were found in the lower
layer of the use envelope.
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MAY2 JUNE 1 JULY 1 AUG. 1 SEPT. 1 OCT. 1
Figure 28. --Aveulage daily water use envelope during *he growing ~sason encompassing a
range of siZvicuZture residue treatment combinations in a Zarch/fir forest.
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