Environmental Assessment

AFFECTED ENVIRONMENT & ENVIRONMENTAL CONSEQUENCES CHAPTER 3
maintenance program that repairs and corrects erosion problems and damage, and implements diligent
monitoring of activities for resource damage and unauthorized use of undisturbed areas (Scenic Resources
Report page 6).
Grazing, including the construction or reconstruction of improvements, would have no measurable
cumulative or cumulatively significant effects on scenic resources under any of the three alternatives.
None of the other current, on-going or reasonable and foreseeable actions has any identified cumulative
effects on scenic resources under any of the three alternatives.
Soils
Introduction
The long-term sustainability of forest ecosystems depends on the productivity and hydrologic functioning
of soils. Ground-disturbing management activities directly affect soil properties, which may adversely
change the natural capability of soils and their potential responses to use and management. A detrimental
soil condition often occurs where heavy equipment or logs displace surface organic layers or reduce soil
porosity through compaction. Detrimental disturbances reduce the soils ability to supply nutrients,
moisture, and air that support soil microorganisms and the growth of vegetation. The biological
productivity of soils relates to the amount of surface organic matter and coarse woody debris retained or
removed from affected sites.
Forest soils are considered as a non-renewable resource, as measured by human life spans, and
maintenance or enhancement of soil productivity is an integral part of National Forest management.
Therefore, an evaluation of the potential effects on soil productivity is essential for integrated
management of forest resources (Soils Report page 4).
Existing Condition – Landscape Characteristics
Approximately 70 percent of the planning area is comprised of gently sloping plains and uneven lava
flows that surround Pine Mountain, a composite volcano. Pine Mountain and its associated landtypes
comprise another approximately 20 percent. The remaining 10 percent is associated with miscellaneous
landtypes (cinder cones, buttes and escarpments) that occur in scattered locations in the planning area.
Slopes generally range from 0 to 30 percent on the dominant landforms. Steeper slopes (30 to 70 percent)
are associated with the smooth-to-moderately dissected side slopes of Pine Mountain, escarpments of
buttes and ridges, and a few scattered cinder cones (Soils Report page 6).
Most of the water yielded from these lands is delivered to streams as deep seepage and subsurface flows.
Surface runoff generally occurs only in areas with shallow soils and disturbed sites during high intensity
storms or when the ground is frozen. There are no perennial or intermittent streams within the planning
area. Any channeled surface flows within ephemeral channels are discontinuous and of short duration.
With the exception of the youngest lava flows, over 90 percent of the planning area has been covered by a
moderately thick layer of volcanic ash and pumice from the Mount Mazama and Newberry volcanic
eruptions. These deposits consist mostly of sand-sized particles (Soils Report page 6).
Dominant soils are moderately deep (20 to 40 inches) to deep (greater than 40 inches) with loamy-sand
textures and have moderate productivity potential for the growth of vegetation. The locations of
proposed activity areas meet criteria for land suitability that would allow them to be regenerated or resist
irreversible resource damage.
Soils derived from volcanic ash tend to be non-cohesive (loose) and have very little structural
development due to the young geologic age of the ash deposits. These ash-influenced soils have naturally
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