Ski runs are not created equal.

• Position: Ecology

Building a new aid run by bulldozing a mountainside rather than cutting only its shrubs and trees is far more damaging ecologically, yet might offer only a week's earlier start to the downhill season, indicates a study from the University of California, Davis--and even that extra week of revenue may be offset by higher summer maintenance costs.

[ILLUSTRATION OMITTED]

Ecologist Jennifer Burt's study of seven winter resorts in the northern Sierra Nevada mountain range found that ski slope grading, compared to clearing, is worse for plant abundance and diversity, reduces soil depth and fertility, and promotes erosion.

"Most large downhill resorts in the U.S. are on lands managed for the public by the USDA Forest Service, which is supposed to encourage multiple uses while attempting to protect the ecosystem, but ski areas are managed primarily for recreation, when they might be better managed to minimize negative impacts on water storage, nutrient cycling, and biodivarsity."

"Cleared" runs are created by cutting and removing tall woody vegetation as needed to create open skiing and riding pathways, but leaving the top layers of soil and their existing seed bank largely intact.

"Graded" runs are cleared--and then machine-graded or leveled to remove bee stumps, boulders...