About 30 years ago when I was in college, there was a very nice area with a major waterfall in it. It was private property but the owner didn't mind people enjoying it. There were hundreds of people a day going in to enjoy the hiking there.

I went there several times a year for several years. Never noticed any undue wear on the place.

Then trail riding became a big thing. The next time I went there, I got nearly clipped several times while walking the half mile. Riders bombed pretty fast even past little children. The next spring when I went, there was massive erosion that was pretty clearly caused by bike tires tearing the ground up. A month later the owner closed off a beautiful area that had been open to everyone for 100 years. It's still closed. It didn't leave me thinking much of trail riders. Even on the trails that have been prepared to take the abuse of a bike, the 1 in 10 riders that are complete jerks really ruins things for me. I have to go to very, very out of the way trails to enjoy a hike anymore. I was extremely nervous when I had small children on the trail with me. I skipped going on some trails because of the danger.