Most of the tree damage articles and studies I've seen over the years were focussed on the arbutus which has thin, paper-like bark and a vulnerable trunk. Because of where it grows it can often be a tempting "anchor" for someone's stern tie line.
However bark damage is bark damage and while a tree may make an effort to repair the damage it offers a foothold to insects and disease.
Humans have perfected the art of excusing away virtually any behavior even if that behavior is detrimental to some other living thing. "Never seen any damage," "things heal themselves" and "been doing it for years and never seen a problem" are classic examples which, while contrary to the findings of deliberate, carefully conducted studies and research often carried out over many years, make the behavior "okay" in the minds of people to whom convenience and habit are more important than the well-being of something other than themselves.
A fair number of the problems on this planet, not just the health of coastal trees, are tied directly to this attitude I think.
We don't stern tie very often because our current time limitations restrict where we're able to go with our PNW cruising boat. But when we do we find it takes little more effort to do it with no impact on the shoreline than to make convenience the number one priority over everything else.
I certainly don't expect anyone to change what they currently do. I learned a long time ago that this is wishful thinking. One of my favorite truisms I've mentioned other times came from a woman who when we were all very young was our floor director at the television station in Honolulu where we worked. Years later in an e-mail exchange about people we'd worked with I enquired about a particular person I'd heard nothing about since leaving Hawaii. I wrote something like, "What's ______ doing these days? Has he changed from the way he used to be?"
My friend wrote back, "Oh Marin, you know people don't change. They just get more of the same."
If there is one thing I've learned for sure in my life thus far it's that she's right.
Somebody on this forum-- I suspect it was psneeld-- made an astute comment in one of the endless "best anchor" threads and that was that no matter what was said in the thread, no matter how eloquently people wrote in favor of their favorite anchor or anchoring technique, it would not cause a single person to change what they currently do, how they do it, and why they believe in it.
I believe the situation is the same with regards to stern tying to shore.