Bus service on the MBTA’s 73 route was impacted Sunday after a tree fell on Belmont Street in Watertown. A tree fell across a major road in Watertown Sunday afternoon, impacting MBTA bus service in Watertown. The tree fell on Belmont Street near Prentiss Street, according to an Instagram post from the Watertown Fire Department. It struck wires used by the MBTA’s 73 bus. View this post on Instagram Early this afternoon a large tree fell across Belmont Street at Prentiss Street.