ENVIRONMENTAL CONSEQUENCES in rocky mountain coniferous ...

Meanwhile, small shrub cover changed very 1 i ttle overall , accounting for 20 percent
before harvesting and 22 percent 4 years after harvesting. The "other" cover reflected
increases found in the herbs and shrubs--i t decreased from 43 percent preharvest to 33
percent 4 years later.
SILVICULTURE TREATMENT EFFECTS
Looking at the silvicul tural systems overall , and combining residues management
treatments, we found that absolute values of herbaceous cover 4 years after harvesting
had increased an average of 13 percent on group-selection cuttings, increased 6 percent
on clearcuts, but decreased 3 percent on shelterwoods. In relation to preharvest
values, this was equivalent to a 38-percent increase on group selections, a 15-percent
increase on clearcuts, and a 7-percent decrease on she1 terwoods (fi g . 12). Because
cover sampl ing was 1 imi ted to 100 percent with our study method, any increases or
decreases in herbaceous cover were reflected in the cover of small shrubs and other
cover i tems 1 i ke 1 i tter and woody material . Small shrub cover increased most on clearcuts,
increased moderately on shelterwoods, and decreased on group selections in relation
to preharvest values. The "other" cover decreased on a1 1 cutting - methods in
direct response to increases in herbs and small shrubs.
2
YEAR
Selection
Fiuure 12.--Posthawest chunge irz herb cover in reZation to ppreharvest cover
. 08tha*vest by si tvicu tture treatment.
(irewaet )