ENVIRONMENTAL CONSEQUENCES in rocky mountain coniferous ...

RESIDUES TREATMENT EFFECTS
As described earl i er , s i 1 vi cul ture treatments , accompl i shed by harves ti ng , reduced
volume of understory vegetation on the various sites . However, when data from the
three si 1 vi cul tural treatments were combi ned, we found that residue treatments a1 so
substantially affected understory vegetation. The residues treatment that sought to
protect understory trees during harvesting a1 so resulted in substantially less loss of
the associated understory vegetation. As shown in figure 6, harvesting with this
treatment (understory protected) reduced shrub volume 2 years after harvesting to 35
percent of its preharvest level. At the other end of the scale, the two treatments
that burned remaining res idues reduced shrub volume 2 years after harvesting to less
than 3 percent of their preharvest volume. Little of the shrub volume left after
harvesting remained after burning. Intensively removing a1 1 residues resulted in an
intermediate loss in shrub volume.
0 2
YEAR
Understory Protected
All Residues Removed
l nterrnediate Utilization and Burned
Conventional Utilization and Burned
Figure 6. --Effect of four residues management treatments on understory shmb vo Zwne
2 and 4 years after harvesting in a Zarch/fir forest.