Costs and scheduling are considered in detail in Chapter 14 using SNAP.

As previously discussed in chapters 6 and 10, the most significant limiting habitat parameter within the planning area is tree height. Due to the severe wind shear trees rarely exceed 90 feet. This will be a major consideration when examining thinning options

With passive management, the upper Washougal watershed will achieve 85% habitat within 5 years. Although this high percentage of habitat is a desired result, there is no revenue gained through this period. Therefore, passive management is not the preferred design option for the planning area. The no harvest, pre-commercial thinning, commercial thinning, and regeneration harvest results are contained within coverages located on the data CD "Washougal 98".

Pre-commercial thins were defined as removal of the smallest 30% of the stand based on DBH. After modeling this in 10 current dispersal non-habitat stands, it was determined that none of these stands would recover to reach habitat within 25 years. Relative density and height were the two HCP criteria that were low.

To model pre-commercial thins, 10 dispersal non-habitat stands were thinned in 1998 and grown to 2023. The table below highlights habitat requirements from two of the dispersal non-habitat stands subjected to pre-commercial thinning in a LMS-derived chart written by Jim McCarter of the UW Silviculture Lab. The inability to reach habitat over 25 years in these two stands is a function of the low relative density. This is logical as the trees taken are the worst in the stand leaving fairly high heights and high diameters with low relative density.

The 1998 volumes for Table 13.1 and 13.2 were calculated using a volume program called TARIF. The projected volumes were calculated through LMS using a different volume equation. This accounts for the slight drop in volume between 1998 and 2003. This changes the volumes slightly and the trend through out the 25 years stays the same.

In the case of pre-commercial thins, habitat is constrained by the height of standing trees and the relative density. It would be possible to raise the average height if the thinning were to take out the shortest 30% of the stand. This however is not practical for a sawyer to determine from the ground as therefore not an option. Thus, pre-commercial thinning is not an option due to habitat constrainsts.

Pre-commercial thinning not only fails to meet habitat goals but also brings in no revenue. It is an expensive operation for the low returns it brings in the Washougal planning area. It therefore will not be considered due to economic practicality as well.

For the planning area, commercial thins were considered 40% from below based on diameter. Ten dispersal habitat stands were commercial thinned in 1998 and projected to 2023. The results matched the pre-commercial thins. There was no quick release that elevated stands into habitat within 25 years. Nor was the cost of thinning justified by the cut volume. In both cases, thinning from below means the trees with the poorest grade are harvested. This suggests that the wood harvested would not make much profit on the market. The table below shows the habitat requirements of two dispersal habitat stands thinned in 1998.

The current stands in the Washougal watershed are too mature to consider commercial thinnings. There would be no growth release of ten associated with thinning on younger, less stagnant stands. This causes the relative density to drop and never recover. Due to the habitat reasons alone, commercial thinning is not considered an efficient silvicultural strategy

Pole thins are not a viable option due to the habitat constraints and the condition of the standing timber. Pole thins require timber to have low taper and few branches, the opposite characteristics of the trees in the planning area

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There are at least two old growth stands within the Washougal planning unit. These are the only stands that have enough volume to warrant a commercial thin. There may be other exceptional stands in the area that will be identified with the updated FRIS survey.

Regeneration harvests have seemingly severe initial effects on the landscape. However, our models predict that they have approximately the same impacts as thinning as far as removing acreage from the habitat criteria. It may then afford the DNR to start over with a planted stand under intense management, which in the long run, will be more beneficial towards the development of habitat. Specific volumes and growth associated with regeneration cuts will be discussed in detail in Chapter 14.

Regeneration cuts will provide the most revenue for the Skamania County trust. Through regeneration cuts the DNR will be able to generate sufficient revenue every year while keeping harvesting costs down.

The severe site conditions in the upper Washougal watershed and the relative maturity of the trees limits the range of silvicultural operations. The stands are currently in a stagnant, unproductive. Because of the advanced age of the trees it is not expected that they would respond to the increase in growing space provided by thinning. Thinnings and pole cuts are therefore not biologically or economically efficient. Further, thinning removed stands from compliance with the HCP criteria for as long as 30 years. It is therefore recommended that harvest operations in the planning area be limited to regeneration cuts. Regeneration harvests may present the best opportunity to develop revenue for the trust while increasing the productivity of the watershed through intensely managed planting.

The DNR may also want to redraw the HCP map when the FRIS data is released with all riparian buffers separately classified. The riparian buffers tend to contain the best growing in the watershed and are therefore the areas most likely to achieve habitat the earliest. the total acreage of the watershed in compliance with the HCP will be underestimated if these areas are included in adjacent stands. This is due to the significantly higher growth rates that over time could split stands into two different structures.