This is the Bikewright definition.
Trail Trash -(n) Trail Trash is all the dirt/leaves/small rocks/pine needles and other trail crap that sticks to your legs while riding or goes down inside your boots or shoes while hiking or backpacking that can cause hot spots or blisters,
Trail Litter-(n) Trail Litter is all- (just look at the picture)
This was just from a short loop on the trails and back to the house! You would think with all the folks that ride with some type of pack on that there wouldn't be anything on the trail. So the next time you are on the trail just take a second or two and stop and pick-up some trail litter.