Tom/Barb,
I studied forestry at UW. The West Side is definitely different than other drier forest types in eastern WA and other part so of the western US. Large fires on the West Side occur infrequently, but can cover a lot of acreage due to the accumulation of very large amounts of organic matter on the forest floor. In old growth forests, it is usually not possible to travel through them except by walking on fallen dead trees.
Over 90% of the nutrients in a tree are in the foliage. Decaying organic matter adds little in the way of primary and secondary nutrients to the soil profile. Decompostion ties up primary nutrients especially N making it unavailable to the plants through nitrification.
Your idealized view of Douglas fir/western hemlock West Side forest is overstocked with a large amount of organic matter on the forest floor. It is not what a managed stand should look like.
