ECOLOGY OF CELTIS RETICULATA IN IDAHO

The small deciduous tree Celtis reticulata (netleaf hackberry) reaches its northern limit in Idaho, where, contrary to most of its western range, it often occurs as an overstory dominant. Two hundred fifty stands of this tree were sampled throughout Idaho. Celtis is slow-growing, averaging 4 m tall at 50 yr, and long-lived (to 300-400 yr). It occurs in a variety of habitats, from riparian to rocky uplands. Trees grow best where topographically sheltered, such as in draws and narrow canyons, and where soils are loamy. Although plants grow more slowly as surface rock cover increases, stands are often associated with rock, with a mean surface cover of 39% rock. Differences in growth rates were unrelated to parent material and aspect. Most stands are reproducing, in spite of habitat degradation caused by overgrazing, alien plant invasion, and increasing fire frequencies. Stands are typically represented by one dominant cohort; however, young, even-aged stands are rare and are generally found along waterways on stream terraces or at the high-water line. Although slow-growing, C. reticulata shows promise for land managers interested in site enhancement. This native species is long-lived, produces fruit used by wildlife, and provides structural diversity in a semiarid landscape (with a maximum height of 12 m) in areas that are becoming increasingly dominated by exotic plant species.