Site Factor Relationships with Volatile Oils in Big Sagebrush

Abstract

The volatile oil content in big sagebrush leaves varied greatly on different sites, ranging form 3.5% of the air-dry weight in short plants on poor sites to 6.0% in tall plants on favorable sites. A regression equation using selected site factors accounted for 91% of the variation in oil content. Oil content was most highly correlated with sagebrush size and the amounts of magnesium and phosphorus in the A horizon. Short big sagebrush plants on poor sites should be maintained as forage plants, but tall big sagebrush plants on favorable sites should be replaced with other more palatable species. Chemicals which can reduce or retard volatile oil production should be studied.