Rangers armed with silicon putty check the sculpture for cracks every fall but were unable to chip away at the black and green lichen that was spreading across the surface.

• 每年秋天，公园管理员都会用硅腻子检查雕像的裂缝，却不能清除掉蔓延覆盖在总统面部的黑色和绿色苔藓。