Final Environmental Impact Statement Rio de los Pinos Vegetation ...

Final Environmental Impact Statement Rio de los Pinos Vegetation Management Project
would continue. Units that currently have large beetle outbreaks would continue to experience
extensive tree mortality, most likely until the mature spruce component is almost entirely lost.
Loss of live basal area due to spruce beetles has already occurred to varying degrees within the
analysis watersheds, with some units experencing over 50% mortality. The loss of live basal
area could lead to increases in annual water yield and late season stream flows, as well as
changes in peak stream flows. See Section 3.6 Watershed and Aquatic Resources in the EIS for
detailed discussion regarding beetle epidemics and potential effects to watershed hydrology.
The potential effects to stream habitat by the loss of live basal area could be mitigated by
increased growth in understory vegetation and well established riparian vegetation; as well as
provide a source for woody debris and large woody structure which is important for many
aquatic species including trout and macroinvertebrates. On the other hand, high stand-level
mortality rates can lead to increased runoff and higher flows which can increase streambank
instablity and rates of soil erosion. Increased sediment loading in the streams could lead to loss
of spawning and overwintering pool habitat which could be detrimental to trout and aquatic
insects which are important as a food source.
The No Action alternative could potentially affect the trout population due to the extensive tree
mortality rates within the analysis area and the possible corresponding increase in erosion and
stream sediment loads.
Alternative 2 – Full Salvage Harvest
In this alternative, approximately 13.1 MMBF would be harvested from 878 acres by salvage
logging dead and dying Engelmann spruce. This would be accomplished with ground-based
(tractor) logging methods. No green, uninfected spruce trees would be harvested and no green or
dead subalpine fir would be harvested. Exceptions to this are those trees that must be removed
from skid trails, landings, or for safety reasons, and scenic patch cuts.
Following removal of the dead or dying spruce, the Forest Service would plant Engelmann
spruce seedlings on those areas where post-sale reforestation surveys indicate that stocking is
below the minimum standard of 150 trees per acre.
This alternative would cause more surface disturbance than Alternative 1 or Alternative 3 due to
the increased size in harvest area and harvest volume; and corresponding increase in ground
disturbance associated with skid trails, roads, and heavy equipment operation. Currently, most
streams and riparian areas within the project area are in good to robust conditions and any fish
habitat concerns within the analysis area tend to be site specific and not an overall threat to the
fish populations throughout the Rio de Los Pinos drainage. All surface disturbances would be
adequately buffered to prevent direct impacts to the water influence zone and riparian areas.
New surface disturbances from skid trails and landings would be limited to acceptable levels
established in the Forest Plan.
Road work is included in this action alternative and some surface disturbances would occur
during pre-haul road maintenance, road reconstruction, road closure and rehabilitation, and
during construction of a short temporary road. The short-term impacts during these activities
Chapter 3 – Affected Environment & Environmental Consequences Page 3-64