An optical phenomenon in which some species of dew-covered plants become strongly retroreflective. On a warm summer evening when a beam of light, such as car headlights, illuminates dew- covered trees, the scene is reminiscent of snow-covered trees in the moonlight. Four things must be present for the sylvanshine to be seen: the proper species of tree, the proper season of the year, dew-covered leaves, and a view looking directly down the beam of light illuminating the tree in an otherwise dark scene. The sylvanshine is closely related to the heiligenschein. Fraser, A. B., 1994: The Sylvanshine: retroreflection in dew-covered trees. Appl. Optics, 33, 4539–4547.

Sylvanshine is an optical phenomenon in which dew-covered trees of species whose leaves are wax-covered retroreflects beams of light, as from a vehicle's headlights, sometimes causing trees to appear to be snow-covered at night during the summer. The phenomenon was named and explained in 1994 by Professor Alistair Fraser of Pennsylvania State University, an expert in meteorological optics. According to his explanation, the wax on the leaves causes water to form beads, which become, in effect, lenses.