ENVIRONMENTAL CONSEQUENCES in rocky mountain coniferous ...

All residues management treatments altered the proportions of shrub leaves, small
stems, and large stems from that found in the mature forest. An example of three
shrubs that normally have widely different proportions of leaves, small stems, and
large stems i 1 lustrates these residue treatment effects (fig. 19). Residue treatments
that included burning affected leaf and stem proportions the most. Differences were
most pronounced in the larger shrubs. As expected, treatments generally effected a
shift toward higher proportions of leaves and small stems at the expense of large
stems. For example, leaves accounted for only 4 percent, and small stems 5 percent, of
the total biomass of maple in the mature forest. Broadcast burning changed this to 22
and 21 percent, respectively, 4 years after harvesting. Similar trends were apparent
in ninebark, a medium-size shrub, and to a lesser extent in thimbleberry, a smaller
shrub.
ACER PHYSOCARPUS RUBUS
Figure 19.--Components--leaves, smaZZ sterns less than 4 mm (0.16 inch) diameter, and
Large stems more than 4 mi (0.16 inch) diameter--of three typical shrubs 4 years
after harvest cutting in a Zarch/f-ir forest.
The understory-protected treatment resul ted in a relatively mi nor shift in the
shrub components of maple, but produced a moderate shift in the other two species at
the 4-year measurement. Removing all the residues resulted in a moderate shift for
all three species.