To keep its evergreens from turning into Christmas trees, the University of Idaho is spraying each one over 8 feet tall this year with a potent mixture of skunk scent and coyote urine.

David Rauk, physical plant forestry manager at the Moscow school, said the smell is unnoticeable at outdoor winter temperatures but becomes "extremely offensive" when a treated tree is brought inside and warmed up.The spray will dissipate by January, Rauk said.

University of Idaho forest researcher Kasten Dum-roese recommended the mixture as a way to help groundskeepers combat an annual assault on trees at the school. Similar solutions are available at hunting stores and have been used successfully in other cities, including nearby Pullman, Wash.

Several trees are cut down each year, and Rauk said anyone caught with a campus conifer could be charged with grand theft.

An 8-foot evergreen costs about $500 to purchase, plant and maintain for several years, he said. A spruce worth that amount was stolen this year before the smelly solution could be applied.