Hey fellow park users : these young trees have a tough enough time surviving their youth* in big city parks as it is! Damaging their tender young bark with bike locks is so avoidable --
Lock your bike to itself if you're close by. If you are leaving your bike unattended a long ways from where you are -- such as this one -- find a bike rack along the perimeter of the park.
Trees take up water and return nutrients to its roots via the xylem and phloem, which are thin layers at bark level. If the bark is damaged it damages the trees ability to function. If the damage is done when the tree's bark/xylem/phloem is young and tender and thick bark hasn't yet formed it is more serious.
(BTW, boo to the corporate advertising in the park too, even if those petunias are rather pretty.)
* vandalism. dog pee, drought, among other things....