Old growth.....hmm.....at the risk of being a cynic.......
Environment extremist (Ee's), who seem to have all of the answers, don't ever give a definition do they?
I interpret their "old growth" forest as one that was naturally seeded, unattended throughout its evolutionary growth, Matured to the point that it contains the upper echelon of trees that will develop in that particular ecosystem and canopied over such that no new growth can exist amongst those lucky enough to have found a spot all their own.
Now that means that "Man", the one thing on this planet that Ee's think shouldn't exist, isn't welcome because his needs (fire, clothing and shelter) would endanger these plants that had become "king of the mountain".
So, I guess the definition according to this blurb is Old growth means evolutionary mature regardless of size.
Trees grow old the same as people. If we, as a part of the ecosystem, need a tree then we are better off taking it before it reaches declining maturity and before it has inhibited the growth of other trees that would replace it.
My Granddaddy was a fine old gentleman. He was a tribute to the society. He was a newspaperman, railroad man, clergyman and Judge. If someone had needed an organ for transplant and his carcass had been available, he would have made an excellent donor. By the time I new him in his declining years his organs were worn out and he was sick. Using him for transplants at the time of his death wouldn't have benefited anybody for very long. (I don't support genocide either.)
Mature Trees or as my forester calls them, "Overly Mature", don't benefit anybody either.....except for perhaps visual gratification. They are generally too big to handle. They have declining root systems and lack stability. Disease and rot in their boles inhibits their use for lumber and huge canopies prevent the development of future trees. Ferns and mosses are about the only thing that will co-exist in an environment like that and their density may prevent the reseeding of an old tree when it naturally succumbs. Perhaps a forest should first be considered "old growth" when it can still produce a product and is on the verge of declining.
If you take the stance that humans belong in this ecosystem then I agree with you that 'Logging is Good'. Of course it must be performed properly and who else would be better to judge than the logger whose lively hood depends on it. It is unfortunate that the people who get the most press shoot from behind a desk and are "Educated Beyond Their Intelligence".
So, keep on teaching. I think you're on the right track.