Cool info. Burnham....
I have always wondered, when a big tree falls in the woods on it's own, how is the soil decompacted?
There's more than 50% of the original forest left at Hood? or 50% hasn't been logged? I remember when those folks were protesting up there in 99'-00'? they had some pretty wild a$$ figures.
Iv'e heard alot of random info. over the years and it's good to hear from a pro like you.
As for cuttin' those big trees over the road... I'm all for it, saftey first
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Thanks again for the post and pics Burnham, high quality.
I can only give you my take on your first question...it would be uncommon for a naturally falling tree to hit hard over any significant proportion of it's length. The ground isn't smooth or flat and there are always obstructions like other fallen trees on the ground and standing trees to strike that would mitigate against a hard, soil compresssing strike. The other factor is the huge number of organisms in a natural stand that are active in the soil...burrowing, foraging, all that sort of thing. So natural processes decompact soil at a furious pace, better than we could achieve with all our technology we wield in the 'burbs and urban environments. The key is having a sufficiently intact cohort of this type of organisms to do the deed. It's there where I work, and usually not where most of you folks do.
As to your second question...for my answer to click for you, I'd guess you are going to have to re-construct your vision of what a completely "original forest", as you put it, looked like before European emmigrants came to this part of the continent.
There never was, ever, an uninterrupted forest of oldgrowth covering the +1,250,000 acres that today are designated the Mt. Hood National Forest. For example, not all of that ground could support a stand of trees because it was either alpine ecotype, talus slopes, wet meadows, bodies of water, etc.
Natural disturbances have always occured, taking areas of mature forest back to open ground...things like lightning-caused fires, floods, mass land movements, volcanic eruptions. Another thing that happened to modify forested acres actually was human management in the pre-history era...native peoples actively used fire to create openings to improve hunting conditions and habitat for preferred food species like huckleberries...hundreds of thousands of acres on the eastern side of this Forest were treated that way from the time shortly after the glaciers retreated some 15,000 years ago, when those people first got here from east Asia...or wherever.
Another interesting factor is the length of time the current forest composition has existed here. Core samples from natural lakes in the region looking at pollen deposits have shown that the current species mix of Douglas fir, western redcedar, hemlock, noble fir, alder, and maple, etc. has only been so for about 6,000 years. Those native peoples where burning a completely different mix of tree species back when they started. Long term climate change is generally thought to be the reason for the shift in predominant species making up the forests of this region over that time frame.
Last, what is the definition of "oldgrowth"? There is currently a move here in Oregon to legally define oldgrowth as anything over 80 years. Now I can't say I know when a forest is old enough to be called oldgrowth, but I know for certain that 80 year old Douglas firs are not even close to maturity, let alone ancient.
Ok, so back to your question. Since the late 1920's when harvests first started on the Mt. Hood NF, we have cut less than 50% of the economically viable to harvest acres. That is quite a bit less that 50% of the total acres. My educated guess would put it at about 35-40%.
We have not harvested much of anything except by commercial thinnings of managed stands since the early 2000's. Stands people like me planted, released, and pre-commercially thinned back 35 to 50 years ago.
. Oh, well...best laid plans and all that 
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I love these old threads 
