Spy Mesa Yields Better Understanding of Pinyon-Juniper in Range Ecosystem

Abstract

A 2-year study on the Spy Mesa relict of the Arizona Strip provides information concerning the natural occurrence of pinyon-juniper in range ecosystems of this area. The 40-acre relict is unique because there is a wide variety of soils and natural fires have occurred over the past 50 years. The plants have been grazed by rodents and mule deer and yet they have been inaccessible to livestock. This study reveals that, following natural fires, grass became significant in the plant community only on soils that had sandy surface textures. Pinyon-juniper was the dominant species in the absence of fire, regardless of the kind of soil. Those soils having a vesicular, massive, or platy surface layer did not produce significant quantities of grass at any stage of plant succession.