ENVIRONMENTAL CONSEQUENCES in rocky mountain coniferous ...

MEAN CONSUMPTIVE USE -ALL YEARS (1976- 1978)
1 S helterwood
Group Selection
Figure 17. --Water use summary for the second through the fourth year after the 12
sC ZvicuZture and residues trea-bments were imposed in a Zarch/fir forest.
The most conspicuous water user is the understory-protected treatment in the
shel terwood. It consistently used more water than the uncut-control areas. The
differences became even more conspicuous as the study progressed. However, this same
understory-protected treatment was little different than the other residue treatments
on the group selections and clearcuts. As it turned out, a1 though there was a deter-
mined effort to save the understory trees and shrubs in this treatment, only in the
shel terwood was this accomplished very effectively. This is shown in the analysis of
the understory vegetation of these treatments (Schmidt 1980). These water use data
correspond to the unders tory-vegetation measurements -- the greater the residual under-
story vegetation, the greater the water use.
The residue-removed treatment ranked second in water use, but this was most
obvious on the clearcuts and group-sel ection cuttings . This corresponds directly with
the dramatic increase in herbs and small shrubs on this same combination of treatments