On the road leading to the Department of Energy's Oak Ridge National Laboratory, drivers may notice that many of the green trees lining the entrance to the lab are dappled with brown leaves. At first glance, the sight isn't extraordinary, as deciduous tree leaves turn hues of oranges and browns before falling to the ground each autumn. Yet, just weeks past the summer solstice, this phenomenon is out of place and is in fact evidence of another natural occurrence: cicada "flagging."