In fall 2010, Dr. Todd Barkman and his botany class discovered an individual of dwarf hackberry (Celtis tenuifolia), the first of its species to be recorded in Kalamazoo county. A plant associated with oak openings, the dwarf hackberry is an uncommon species with only 30 documented occurrences in Michigan. Based on the canopy cover, vegetation and soil composition, this site may be the remnant of an oak opening. The fire-dependent savanna ecosystem typically has a canopy cover between 10 percent and 60 percent, predominantly oak trees. Oak openings are found on dry-mesic loams and serve as the transition from tall-grass prairie to woodland habitats. The construction of roads and towns, expansion of agriculture and subsequent suppression of fire led to the conversion of many oak openings into woodlands or urban landscapes. Only 0.02 percent of these globally rare ecosystems still exist in Michigan, with only two documented occurrences.
About the dwarf hackberry
Unlike the common hackberry, the dwarf hackberry tends to have shorter fruiting pedicels and drupes that are more orange-red than purple. These fruits remain plump and smooth when dry, while the fruits of the common hackberry strongly wrinkle. The leaves of the dwarf hackberry have margins that are more entire, especially the bottom third of the basal end of the leaf.
The bark of dwarf hackberry tends to be light gray in color while that of the common hackberry is more tannish-brown. The trunk has muscle like ridges as in Carpinus caroliniana and has more smooth bark with infrequent warty protuberances. As implied by its name, dwarf hackberry grows to a lesser height and trunk diameter than its counterpart the common hackberry.
Among the dwarf hackberries on WMU property, near Stadium Drive apartments, are the three largest dwarf hackberries in the state.