Western North American Juniperus Communities: Patterns and Causes of Distribution and Abundance

Abstract

About 60 species of Juniperus are found across the Northern Hemisphere, from near the equator in Africa and Central America and north to the Arctic Circle in Alaska, Canada, Greenland, Norway, and Russia (Hora 1981). In North America, 13 species of Juniperus have been reported (Little 1971; Elias 1980). Juniperus communis and J.horizontalis are found in the Far North across Alaska and Canada, while J. flaccida and J. deppena occur south into the mountains of southern Mexico. In the eastern United States, J. virginiana is the most common species of Juniperus, whereas in the intermountain West J. monosperma, J. osteosperma, and J. scopulorum are common. In Oregon and northern California, J. occidentalis is the major species of Juniperus and J. californica is largely confined to California. The distribution of J. ashei and J. pinchotii is mostly in central and western Texas, and J. silicicola occurs along the Atlantic and Gulf Coasts.