There was a period of time when all of the active preservation societies (Sierra Club, etc.) were trying to get Vibram soles out of the woods. If you've ever spent time re-building heavily used trails, you'd probably feel the same way. Along most of the larger trails, i.e. The Appalachian Trail, The Long Trail, The John Muir Trail, sections are
constantly re-routed to allow the forest to heal and restore itself. Sections of steep trails have had log or cement steps put in because the boot tread damage was leading to so much soil erosion that tree that had been standing for years were no longer getting support from the ground and tipping over! This is NOT a problem for the forest. It's a problem for the hiker who is under the tree when it falls.
Obviously if you camp in remote wilderness areas this is NOT a problem and there is little need to worry. The earth does heal, but only if man lets it do so. However when 750 people walk the same trail every day during Autumn to see the view from the top of Mt.Somewhere because it's only a 30 minute hike from the trail head, that trail is going to get some severe damage that isn't going to heal without the help of the trail crew moving the trail over several steps to the left or right. Unfortunately, a lot of heavily used trails
don't have the needed manpower to do trail maintenance. Nobody thought much about acid rain damage 50 years ago. Most of us have seen the results of it today.
Hell, even the old Boy Scout manual from the early 60's was still advocating bough beds. I used one when I was a kid and can state clearly that they ARE a delight.
But at what cost to my kids? Or your kids? Maybe there are enough fir trees in the Upper Peninsular or in the Smokies for everyone to make their own bough beds, but there isn't in New York State or in Ohio.
How much impact we make on our environment will vary from location to location. If you're all alone in 100 sq miles of wilderness you can follow different guidelines than if you are walking the Appalachian Trail in New Hampshire and passing people every 10 minutes during the day. It doesn't take much to keep the forests healthy. It just takes some caring.
Stitchawl