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

Final Environmental Impact Statement Rio de los Pinos Vegetation Management Project
15% of any land unit.”
This standard does not include the permanent transportation system.
The direct effects of logging on soils include soil compaction, displacement, erosion and nutrient
issues. Severely burned soils would occur if slash is piled and burned. Some amount of
compaction, displacement and erosion would be expected. The goal of the harvest will be to
meet standards that require the Forest not to exceed 15% of the area in soil impacts. This would
be accomplished by careful design and layout of skid trails, by harvesting on snow or frozen
soils, and by limiting operations to dry seasons. If soils become too wet, operations shall cease.
Using existing skid trails would help keep soil impacts minimized. After operations are
completed, the use of a winged subsoiler or comparable reclamation measures may be necessary
in some locations to mitigate soil impacts.
Soils in the project area have nutrient limitations based on soil criteria. A portion (50%) of the
fine slash (branches and limbs) would be retained within the forested stand to maintain nutrient
reserves.
Soils of the project area have a high rating for potential mass movement (landslides). A high
rating does not preclude an action but requires more detailed analysis. In order to address
landslide potentials and hazards, two levels of analysis were completed. One is an investigation
of land mass stability using recent air photos to look for landscapes that might exhibit recent
landslide occurrences. The findings of that investigation are contained in a report titled An Aerial
Photography Analysis of Land Mass Stability Hazards in the Proposed Rio de Los Pinos Timber
Sale, J. Rawinski, February 27, 2008. There were no locations showing active mass movement
hazards, and only one small location that would require further ground-checking.
Another level of landslide analysis was the on-site soil investigations that were conducted on
October 2, 2007. During that analysis, no recent mass movement issues were observed or
identified.
Indirect effects include possible mass movement resulting from changes in vegetation and soil
water characteristics. While this is not expected, some small slumps could occur due to a variety
of reasons. Heavy snowpacks, dead trees that no longer transpire soil moisture and other factors
could contribute to some minor slumps, usually less that ¼ acre in size. To reduce risks, any
temporary road construction would occur on gentle slopes and away from seeps and wet areas.
Alternative 1 – No Action
If no action is taken, standing dead trees would soon fall over and begin to rot. As fallen logs
become moist, fungi would begin to break down the wood and return it to the soil. Rotting logs
may provide seedbeds for seedlings. Nutrients would be recycled. Soils would remain healthy.
Wildfire severity might increase as trees fall to the ground, should a wildfire event occur in this
area in some future decade.
Chapter 3 – Affected Environment & Environmental Consequences Page 3-32