Trees on the beach? (Clippings).

Planning a winter vacation in the sun? Instead of lugging a beach umbrella, just look for a tree. Scientists at Purdue University say they may be able to assess just how much protection trees offer against harmful ultraviolet B radiation, according to an article in The Forestry Source.

Purdue agronomy professor Richard Grant and colleagues say they can predict just how much UV-B radiation exposure exists under trees affording varying amounts of shade by considering such factors as the amount of sky visible through a tree canopy, altitude, latitude and time of day.

For example, when 50 percent of the sky is visible through the trees, at latitudes from 15 to 60 degrees it will take about 50 minutes to receive the same amount of sun as would someone standing in direct sunlight, Grant said. A 90 percent canopy coverage offers protection from UVA rays equivalent to applying a level 10 sun block protection.

This latest discovery in sun protection is one more reason to pay attention to America's urban tree deficit, which AMERICAN FORESTS estimated in 2001 at 634 million trees. In the article, Grant cited the importance of planting trees in "multifamily communities and office complexes, especially in urban areas."