Environmental Assessment

AFFECTED ENVIRONMENT & ENVIRONMENTAL CONSEQUENCES CHAPTER 3
Connectivity for all categories is less than adequate in the planning area. The reasons for this include:
road density and road intersections with corridors is high;
LOS is limited and localized; and
corridors are fragmented by non-forest habitats such as xeric shrublands.
Corridors with the objective of linking OGMA and LOS habitats should have a relatively high canopy level,
or upper 1/ 3 rd of site potential. Very few stands within the planning area meet either of these criteria.
The dry forest types found in the planning area do not provide habitat for those species that are highly
sensitive to fragmentation, such as the northern spotted owl and Pacific fisher. Small core areas and
extensive edges would give a competitive advantage to species favoring small grain mosaics over those
requiring larger patches. Fragmentation by past timber harvest has occurred throughout the planning area,
but is not considered significant because there have been no regeneration harvests in the ponderosa pine
types. Regeneration harvest in lodgepole pine types has occurred, but mimics the natural cycle of this
species, which has periodic stand replacement fires. Fragmentation by road and power line construction has
had a greater impact on habitat connectivity within the planning area than past timber harvest (WL report pg
13).
Connectivity and Fragmentation - Late and Old Structure Habitat (LOS)/Old Growth Management
Areas (OGMAs)
All Alternatives: All alternatives would meet standards, guidelines, and direction described in the Eastside
Screens. Under Alternative 1, no treatments would be implemented in designated corridors. Currently
levels on connectivity would be maintained. Connectivity for travel, LOS, and OGMAs would remain less
than adequate because hiding cover is generally deficit across the planning area; road density and road
intersections with corridors are high; LOS is localized and limited; and corridors are fragmented by nonforest
habitats such as xeric shrublands.
Action Alternatives
Alternatives 2 and 3: Under Alternatives 2 and 3, corridors would only be thinned in order to meet their
respective management objective(s), including maintenance or enhancement. Twenty (20) of the 26
corridors have one or more vegetation or fuel reduction treatments prescribed. For connections of LOS and
OGMAs, the Eastside Screens specify that connectivity corridors between these habitats need to be made
by: Stands in which medium diameter or larger trees are common, and canopy closures are within the top
one-third of site potential. Stand widths should be at least 400 ft. wide at the narrowest point. Deer travel
corridors are to be provided where needed by linking stands meeting the clump/unit conditions specified in
the LRMP. Thinning of most of the travel corridors is prescribed in order to prevent future losses to
insect/disease vectors or loss to catastrophic fire. Where thinning is employed within corridors adequate
cover patches would be needed to reduce sight-distance. The combination of avoiding corridors, or where
corridors intersect/traverse treatment units, appropriate PDCs (BG2) would eliminate the effects of the
treatments on corridor goals and objectives.
Table 3-40 summarizes the overlapping of treatments on designated corridors by Alternatives 2 and 3
respectively.
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