15th St.: Why Orange Fencing, No Parking?

Orange mesh fencing surrounds 15th Street tree boxes from P to Corcoran. Why?
Anyone know why orange mesh fencing was put up today around all the tree boxes on 15th Street between P and Corcoran Streets? “No Parking” signs are also posted for this Saturday, August 23, from 7:00 a.m. to 5:00 p.m.