Environmental Assessment

AFFECTED ENVIRONMENT & ENVIRONMENTAL CONSEQUENCES CHAPTER 3
Both of the action alternatives propose mechanical harvest treatments on landtypes that contain sensitive
soils in localized areas. Table 3-30 displays, by alternative, the proposed harvest units that contain small
areas of sensitive soils by category and the total number of acres affected.
Table 3-30 Proposed Mechanical Harvest Units and Acres on Landtypes with Sensitive Soils in Localized Areas.
Sensitive Soil Category Alternative 2 Alternative 3
1 - Slopes greater than 30 percent 226 acres (total)
H02, H04, H07, H10, H11, H42,
P03, P04, P06, P07, P08, P10, P11,
SD01 & SD08
2 - Low productivity sites limited
by frost heaving, low fertility and
climatic factors
3 - Soils with variable depths in
areas of rocky lava flows
4 - Soils with high hazard for
surface erosion
112 acres (total)
H29, H30, H34, P20 & P21
418 acres (total)
H19, H22, H32, H33, H34, H37, P19
& P21
12 acres (total)
H42, P07, P08, & P10
3-107
328 acres (total)
C302, C303, C305, C307, C339, P303, P304, P306,
P308, P309, P310, P311, P312, P314, P315, P316,
P317, P321, P322 & P324
139 acres (total)
C329, C330, C331, C333 & P343
715 acres (total)
C314, C321, C324, C329, C330, C333, C334, C335,
P335, P342 & P343
80 acres (total)
P312, P315, P316, P317, P321, P322 & P325
Figures 3-14 (Alternative 2) and 3-15 (Alternative 3) display proposed harvest units relative to landform
types with slopes greater than 30 percent and/or sensitive soils with high ratings for surface erosion.
These management concern categories of sensitive soils occur only in the Pine Mountain portion of the
planning area.
The majority of sensitive soil acres are associated with landtypes that limit regeneration potential. It is
expected that many of the sensitive areas with steep slopes and high erosion hazards will be included as
untreated patches within and adjacent to the proposed units to meet wildlife objectives. New logging
facilities – skid trails, landings, etc. – would not be constructed in these areas. If timber harvest occurs
within such areas, mechanized equipment would be required to utilize existing facilities except for
mechanical harvesters which would be limited to a maximum of two passes with travel routes 30 or more
feet apart. Activity areas proposed for mechanical treatments on landtypes with slopes greater than 30
percent and/or sensitive soils with high erosion hazards are identified by unit number in site-specific
mitigation measures (EA, Chapter 2).
Soil displacement from ground-based harvest occurs when soil organic layers are scraped away by
equipment or gouged by logs during skidding operations. This type of soil disturbance is most likely to
occur on the steeper portions of harvest units (slopes over 30 percent). Only the Pine Mountain portion of
the planning area contains areas where slopes exceed 30 percent and is therefore the only portion of the
planning area where soil displacement is likely to be a concern.
Surface erosion is not a primary concern under Alternative 2; less than 10 percent of the unit acres contain
soils susceptible to erosion damage. Under Alternative 3, of the eight units proposed for treatment that
contain sensitive soils, only two, P321 and P325, have more than 10 percent of the unit acreage with soils
with high erosion hazards. Use of all reasonable Best Management Practices (BMPs) for Timber
Management and Road Systems would protect the soil resource and control erosion on roads and logging
facilities used during project implementation (Soils Report, page 30).
There are no sensitive soils located either within or in the vicinity of the two regeneration harvest units
proposed under Alternative 2. No sensitive soils are located in the area proposed for tree planting at the
Pine Mountain Observatory under either alternative.