Summary
During the Spring of 1998, the senior class of Forest Engineering undergraduates of the University of
Washington, under the direction of Dr. Peter Schiess, developed a harvest plan for 13,000 acres of state
lands in the Northwest portion of the Washougal Landscape (T03N R05E and T03N R06E, WM) east of
Vancouver, WA (A Management Plan for the Washougal Landscape, June 1998). The report you are
reading today, is a condensed version of the harvest plan proposed to the Southwest Region Department
of Natural Resources. This report focuses on the silvicultural alternatives of harvesting practices as
dictated by the Habitat Conservation Plan (HCP) and economic drive for revenue.
According to the 1997 HCP, at least 50 percent dispersal habitat for the Northern Spotted Owl must be
maintained in each watershed. A recent DNR habitat survey in our planning area near Washougal, WA
concluded that just under 50 percent of the area currently meets dispersal habitat requirements as
designated by the HCP. The habitat criteria are as follows on a per acre basis:

Relative Density Index > 50 (Approximate to 70 percent canopy closure)

Quadratic Mean Diameter (QMD) of 100 largest trees > 11 inches

Height of 40 largest trees from above diameter class > 85 feet

At least three large snags
Due to the harsh growing conditions, we have found that the stands in this area have trouble meeting the
minimum height requirements and the relative density constraint.
The main objectives in creating a harvest plan for this area, then, are to maximize economic return to
the Trust, and to maintain at least 50 percent dispersal owl habitat. In our analysis, we looked at
three different silvicultural options:

Non-Commerical Thinning

Commerical Thinning

Regeneration Harvests (Clear-cutting)
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Using growth models, our analysis has shown that both thinning options in our planning area fail to create
dispersal habitat conditions within the next 25 years. The stands are too mature to recover from thinning
to create habitat in the areas of relative density and minimum height. We have also shown that 85 percent
of the area will reach habitat conditions on its own within the next five years. Since thinning options do
not show benefit in the creation of dispersal habitat, and are much more costly than the traditional method
of regeneration harvests, they were not considered realistic in this area. Furthermore, we believe that it is
reasonable to sustain a harvest of four million board feet a year from the area in regeneration harvests,
and still maintain the HCP requirements for dispersal habitat. A Management Plan for the Washougal
Landscape
outlines a recommended schedule of regeneration harvest units in order to maintain FPA and HCP
requirements, and still sustain a 4 million boardfeet per year harvest volume. Since the initial stand data
available at the time of the analysis was limited, we suggest revisiting our analysis when more stand data
becomes available from the forest inventory (FRIS).
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Table of Contents
Introduction ……………………………………………………………………………… 1
Design Constraints …………………………………………………...…………. 1
Silvicultural Alternatives …………………………………………...…………... 2
Conclusions ……………………………………………………………………………… 3
Recommendations ……………………………………………………………………….. 4
Discussion ……………………………………………………………………………….. 5
Design Criteria ….……………………………………………………...………. 5
Maintain at Least 50 Percent of the Area as Dispersal Owl Habitat …... 5
Provide Economic Benefit to the Stakeholders ………………...…….... 6
Current Stand Conditions …………………………………………....………….. 6
Growth Modeling Using LMS ………………………………………......…..….. 7
Non-Commercial Thinning ……………………….…..………………... 8
Commercial Thinning ……………………………………………….…. 9
Regeneration Harvest …………………….….……………..…………. 10
Habitat Comparison of the Three Treatments …………….…..…..….. 11
Summary of Cost Comparison of the Three Treatments …………………...…. 12
Harvest Scheduling and Optimization ……………………………………........ 12
Limitations with our Models ………………………………………….….…..... 13
Works Cited …………………………………………………………………….……….15
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List of Illustrations
Figure 1. Results of 1997 DNR Owl Dispersal Habitat Survey ………………………... 7
Figure 2. Percentage of Habitat from 1998-2023 Harvesting 4000MBF/yr …..………. 13
Table 1. Two Dispersal Non-Habitat Stands Non-Commercially Thinned in 1998 and
Projected to 2023 ……………………………………………………………………... 9
Table 2. Two Dispersal Habitat Stands Commercially Thinned in 1998 and Projected
to 2023 …………………………………………………………………………...….. 10
Table 3. Comparison of Growth Model Stands with the Habitat Criteria in the Year
2023 ………………………………………………………………………………….. 11
Table 4. Summary Table of the Cost Comparison of the Three Treatments ………….. 12
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