Opposition effect imaged by Keith Beard of Monterey California. ©Keith Beard , shown with permission.

The bright patch is directly opposite the sun at the antisolar point.

At that point each tree shadow is hidden by the tree itself and thus the area looks brighter than surrounding ones where shadows are increasingly visible.

The 'shadow hiding' opposition effect is most easily seen from an aircraft or even when walking as the bright spot moves across the landscape.

The heiligenschein from water drops and light scattering by rocks also make antisolar point glows. This one is definitely shadow hiding - you can even see the individual shadows. The grey insert is a simulation for circular disks casting shadows on a surface beneath.

Next Feature - Martian Opposition Glow