HomeMy WebLinkAbout1999-0217 Marty Main, President
Small Woodland Services, Inc. 1305 Butte Falls Hwy.
Forest & Resource Management Eagle Point, OR 97524
541/826-5306
February 17, 1999
To: Keith Woodley
From: Marty Main
Subject: Fine Tuning of Management Practices on More Geologically Sensitive
Terrain--Units P, Q, and N.
Keith -
As you know, we have begun implementation of stand level treatments in Units
P and Q, based on guidance and directives (with some restrictions) from you and the
Forest Commission. We have initially focused on those areas of reduced concern from
a slope stability perspective, namely subunits Q~ and P3 (see map) Thinning in these
two subunits has largely been completed, and we will be working on piling and burning
of resulting slash in the near future. Once completed, both of these areas will be much
improved fuel-reduction zones, and will provide important and strategic locations with
which to attempt to arrest the spread of developing wildfire.
In implementing these thinning and fuel reduction activities in subunits Q~ and
P3, however, it became clear to me that a more elaborate, site-by-site analysis of slope
stability issues may be necessary in order to successfully achieve land management
objectives as outlined by the City of Ashland. Further, while we have made
adjustments in thinning intensities in subunits Q~ and P3 in areas delineated in Hicks'
original mapping (i.e., left higher stand densities for purported slope stability benefits),
levels of adjustments in thinning intensity in upcoming, untreated portions of Units P,
Q, and N were difficult to determine without input from an engineering geologist.
As per our agreement, Bill Hicks, Engineering Geologist, and I visited Units P,
Q, and N on February 2, 1999 to "fine tune" slope stability analysis and potential
vegetation removal activities in those units. In Hicks' original landslide zonation
mapping, Units P and Q contained relatively minimal cautionary classifications for
landslide potential, but were rated a high hazard due to the presence of the City's water
pipeline that crossed through these units. Four landslide channels cross underneath
supports that hold the City's pipeline in Units P and Q. A re-visit of the supports
during our traverse re-emphasized that they are in structurally poor condition. Further,
the slope gradients at these locations are steep to very steep, often 70 percent or
greater.
Under these conditions, Hicks' initial recommendations were:
1. Maintain a 75 to 100-foot "no thin" buffer along both sides of these four
debris slide channels.
"Specializing in sound forest management for private, non-industrial small woodland ownerships"
Forest Management Plans · Timber Cruising · Reforestation · Thinning O' Stand Improvement · Timber Sales/Administration
February 17, 1999 / page 2
2. Strongly consider a "no action" alternative on slopes greater than 70
percent due to well documented inherent dramatically increased potential
for landslides in these granitic-based soils.
If those two recommendations are accepted, the great majority of the remainder
of Units P and 0 (i.e., subunits Pt, Oz, Pz, and 03) would remain untreated.
As I have mentioned to you and the Forest Commission, it is certainly
reasonable to leave a portion of your ownership untreated at this time, particularly if a
certain resource concem(s), such as slope instability in these case, warrant such an
approach. This is particularly true if other resource objectives are not necessarily
severely impacted by a "no-action" decision.
In this particular situation, fuel reduction in these untreated portions of Units P
and 0 is not a high priority due to (a) existing topographic realities, and (b) the fuel
reduction treatments currently being implemented that will, in effect, surround these
untreated portions of the units. Hicks and I flagged a connecting link between subunits
01 and P3 (see map) where stand density and fuel reduction activities could be
completed along the ridgeline without adversely affecting slope instabilities, thereby
encircling the untreated portions of Units P and O. It is hoped that the U.S. Forest
SeIVice can eventually tie into this work from above, providing yet another increased
level of zonal fuel reduction and wildfire preparedness.
Silviculturally, these units remain moderately to severely overstocked and ideally
stand densities could be lowered. However, these stands in these units are not under as
severe of a threat of demise as those lower in the City's ownership due to increased
elevation, greater precipitation, less current bark beetle infestation, and generally
greater overall vigor. Delaying treatment for silvicultural reasons is possible at this
time, although it should be carefully monitored in the immediate future.
For these reasons, I think it would not be inappropriate to designate these
portions of Units P and 0 as "no-action" locations at this time. It is certainly possible
that stand density and fuel reduction could be implemented on these sites or portions
of these sites in the future.
Hicks' on-the-ground analysis of Unit N produced very similar results as for the
untreated portions of Units P and 0, as so little of the unit is located on slopes of less
than the highest potential for slope failure. Most of the unit is located on slope
gradients approaching or exceeding 70 percent. Hicks' original slope stability analysis
indicated numerous areas of either potential and/or recent slope failure. This leaves
very few sites that lend themselves to stand density reduction without potential
aggravation of slope failure. Although none of the debris slide channels in Unit N
cross directly under the City water pipeline, collective failures in the area in the New
Year's Day storm of 1997 removed one of the supports of the pipeline in the main
February 17, 1999 / page 3
channel just above its intersection with Ashland Creek.
Multiple resource realities in Unit N, then, are very similar to those in the
untreated portions of Units P and Q previously discussed: (1) Major slope stability
issues, with a higher overall potential for slope failure, although the immediate hazard
is less (no immediate crossing under City water pipeline); (2) reduced importance of
this unit from a wildfire management perspective; and (3) considerably overstocked but
under a somewhat reduced threat of total stand demise in the near future. In addition,
understory thinning will be of significantly less value in Unit N both from silvicultural
and wildfire management perspectives due to greater stand differentiation (less stand
stagnation) and a smaller amount of non-commercial stems that could be removed to
improve stand densities and reduce ladder fuels. Even without slope stability concerns,
it is likely that commercial extraction would be needed to effectively reduce stand
densities to more desirable levels in Unit N.
It is my suggestion that the City should undertake a process of delineating
portions of their ownership that should not be entered at this time due to high slope
stability concerns. Hicks' original analysis, coupled with an ongoing "fine tuning" on a
more site-by-site basis (such as occurred in this situation) would form the basis for this
delineation. It is possible that we may want to develop a specific slope gradient (e.g.,
70 percent) and/or topographical situations (e.g., 75 to 100 feet from debris slide
channels of greater than 55 percent) that automatically kick in a "no-action" alternative
at this time. An ownership-wide mapping of these "no-action" locations could then be
developed and be quite useful in resource decision-making, planning, and
implementation.
This delineation of "no-action" locations would not necessarily be intended to be
a permanent designation as much as perhaps a category of "delayed treatment" at this
time. Exceptions to this process in the event of other significant resource concerns on
any given site could be addressed on a case-by-case basis.
This process could provide several important advantages for the City:
1. Clearly demonstrate the City's intent to respond proactively and progressively
with the difficult land management dilemmas associated with decision-making in
steep terrain prone to landslide activity.
2. Facilitate future planning endeavors (e.g., timber sale preparation, potential
thinning and fuel reduction, etc.) and on-the-ground implementation of those
activities.
3. Focus achievement of objectives to a landscape or ownership level perspective
over longer periods of time. Pockets of untreated vegetation will be acceptable,
if not desirable, if a greater percentage of the ownership/watershed has been
February 17, 1999 / page 4
treated in such a way as to reduce wildfire potentials. These pockets can be
distributed in such a way so as not to contribute significantly to wildfire
potentials, while contributing to biological, structural, and wildlife diversity goals.
Spreading out vegetation manipulation over time and space also minimizes
potential impacts to anyone area at anyone time. 1teating every acre of the
City ownership should not be a desired goal at this time.
4. Focus forest and resource management activities on those sites where multiple
resource objectives can be more easily attained, and accomplished in order of
priority.
5. Allow time for development of professional research and expertise regarding
appropriate treatment responses in steep, unstable terrain (e.g., levels of
vegetation that can be removed while maintaining acceptable levels of slope
stability, etc.). This is rapidly developing in the Pacific Northwest, at least
partially in response to political pressure in the aftermath of recent deaths and
property destruction due to landslides. I suspect that significant strides will be
made in this arena within the next five to ten years.
This document, in effect, acknowledges that my suggestions and eventual land
management practices implemented by the City will be evolutionary as we proceed onto
these steeper, more sensitive, and more landslide-prone portions of the City's
ownership.
Sincerely,
Marty Main
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