Certainly you *can* do timber harvesting in a manner that is sustainable, but those "Paul Bunyan" days are a lot closer than you think, especially when you consider that it takes decades to regrow a forest; fir trees aren't annuals like corn.

I know in the Pacific NW, much of what we were harvesting through the 1980s was still virgin old-growth timber -- those sorts of forests are only "renewable" on a time scale of a couple of centuries if what you care about is a diverse ecosystem full of 10 foot wide, 300 foot tall mature Doug Firs.

Even if you define sustainable as 50 year old monocultures of decent sized but still "young" trees, much of the harvesting in the pre-spotted owl days was not sustainable, in that the rate of harvest was vastly higher than rate at which reforested areas were maturing. If you assume 100% reforestation those areas would have eventually come back, but there would have been a long gap -- we would have run out of prime timber and then had a couple of decades of very short supply in the NW before areas regrew.

Moreoever, reforestation was certainly not happening everywhere, not in complete, well-managed ways at least. That was particularly true on some of the private timberlands, notably the notorious Plum Creek company, which was basically strip mining its holdings of trees to pay off high interest bonds (it was formed as a hostile takeover of a couple of smaller firms), and not really giving a crap about future reforestation. Even on USFS lands things could have been better.

Certainly, many of us in the NW suspect that timber companies saw that the long-term future of the industry was in managed plantations in better terrain/climate conditions (i.e., fast-growing pine plantations in the U.S. South), and figured they'd mow down the forests of the NW in a blaze of glory and not really worry about spending the $$$ for proper long-term reforestation. Ditto in British Columbia today.