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

Final Environmental Impact Statement Rio de los Pinos Vegetation Management Project
Existing Conditions
The following table describes existing soil conditions and current soil impacts.
Table 3.7-2 Existing soil conditions and current soil impacts.
Harvest Units Sum of Soil
Impacts by
percent of
activity area*
Nature of Impacts
1 2-4% Some past harvest, compaction
2,3,4 2-4% Some compaction evident in trails
5 3-5% Compaction due to light past
harvests
* Percent of soil impacts on an aerial extent basis within an activity area. An activity area is defined as: An area of land impacted
by a management activity or activities. It can range from a few acres to an entire watershed depending on the type of monitoring
being conducted. It is commonly a timber sale cutting unit.
During on-site visits, skid trail spacings were measured in the proposed harvest units. The skid
trail spacing provides an initial estimate of potentially impacted area. Soil samples using a tile
spade were then observed in the field for compaction to define the percent of skid trails having
compaction. Platy structure, dense layers and wheel ruts indicate compaction. Estimates of soil
impacts outside of skid trails are also estimated including landings, eroded areas, severely burned
soils and displacement.
The Region 2 Supplement allows for a wide range of soil monitoring tools as described below:
“2.42 - SOIL SAMPLING TECHNIQUES. Sampling techniques range from extensive visual
observations to intensive sampling techniques using statistically sound methodologies. The
intensity of sampling must be determined on a case by case basis depending on the values and
risks at stake.”
The sampling techniques conducted on these harvest units is well within the R2 Supplement
requirements.
All of the stands proposed for harvest are currently meeting soil quality standards. This means
that, based on on-site investigations, soil impacts are estimated to be well below the 15 percent
soil standard. Most stands have had only light logging in the past. Compaction is the primary soil
impact.
Direct, Indirect, and Cumulative Effects
All standards and guidelines from the Forest Plan would be implemented and are incorporated
into action alternatives as design criteria. Design criteria are non-discretionary actions that must
be implemented as part of the action alternatives. One of the key soils standards states the
following:
Forest Plan Standard (III-10, Soil Productivity Std #1): “Manage land treatments to limit the
sum of severely burned and detrimentally compacted, eroded, and displaced land to no more than
Chapter 3 – Affected Environment & Environmental Consequences Page 3-31