This is widespread across eastern North America, but concentrated on fertile base-rich soils (and often planted at old home sites). In Ky. it is much more abundant in the Bluegrass region than elsewhere; this pattern also existed in the original woodland (Barton 1919, Campbell 1989). It was probably also concentrated locally in or near lowlands of the Pennyrhile Karst Plain, where remnants of Juglans-Aesculus woodland can still be found, similar to those in the Bluegrass. Both J. nigra and A. glabra are relatively unpalatable to deer (Atwood 1941, Wakeland & Swihart 2009), but termimal buds can become locally favored during spring (e.g. at Shaker Village in MERC; R. Stauffer, pers. comm.). Cattle can also largely prevent regeneration (e.g.. as observed at Griffith Woods in HARR). Juglans, especially J. nigra, also has a reputation for allelopathy due to exudation of toxic juglone into the soil (Willis 2000). But although many crop plants are sensitive, there is little documentation of native species being affected within typical habitats of nigra. Several species appear to grow relatively well under this tree, including Pinus strobus, Asimina triloba, Vitis spp., Acer saccharum, Rubus occidentalis, Ribes spp., Celtis occidentalis, Morus rubra, Robinia pseudoacacia, Quercus rubra, Fraxinus americana, Sambucus canadensis, Trifolium stoloniferum, Helianthus tuberosus, Arundinaria gigantea, Elymus spp. and several other cool-season grasses (Scott & Sullivan 2007; plus pers. obs.). The state champion is in GREE: 166 cm dbh, 36 m tall and 27 m wide (KDF 2020).