Even though several native species of juniper are major ecosystem components south of the Snake River Plains, the distribution and age class of the ones scattered along streams in the Boise Front suggest that these are all sporadic introductions of cultivated junipers, perhaps cultivars of Chinese juniper (Juniperus chinensis), mostly likely spread by birds.  If so, this in turn begs the question of why native junipers, which are abundant elsewhere in southern Idaho, are missing from the Boise Front.