L.
Identity
Unique IDELEMENT_GLOBAL.2.141124
Element CodePDJUG02080
Record TypeSPECIES
ClassificationSpecies
Classification StatusStandard
Name CategoryVascular Plant
IUCNLeast concern
Endemicoccurs (regularly, as a native taxon) in multiple nations
KingdomPlantae
PhylumAnthophyta
ClassDicotyledoneae
OrderJuglandales
FamilyJuglandaceae
GenusJuglans
Other Common Namesblack walnut (EN) Noyer noir (FR)
Concept ReferenceKartesz, J.T. 1994. A synonymized checklist of the vascular flora of the United States, Canada, and Greenland. 2nd edition. 2 vols. Timber Press, Portland, OR.
Conservation Status
Rank Method Rank calculation - Biotics v2
Review Date2024-07-10
Change Date1984-06-06
Edition Date2024-07-10
Edition AuthorsN. Ventrella (2024)
Threat ImpactUnknown
Range Extent>2,500,000 square km (greater than 1,000,000 square miles)
Number of Occurrences> 300
Rank ReasonsJuglans nigra is a tree occurring in rich woods, meadows and fields, and calcareous hammocks in eastern North America from Ontario, Canada and New York west to North Dakota, United States south to Texas east to Florida; it is an introduced species in much of New England and elsewhere in Canada. Native groves of Juglans nigra were once more prevalent in eastern forests, but this species was heavily logged for agricultural clearing and wood products. Additional threats include damage by defoliating insects, fungal diseases, wildfire, succession, wind disturbance, drought, and predation. This species is commonly cultivated, and little is known about trends, but with a large range extent and number of occurrences, Juglans nigra is considered secure. However, this species should be monitored closely for impacts from thousand cankers disease, which was recently confirmed in several eastern states.
Range Extent CommentsJuglans nigra occurs natively in North America is from Ontario, Canada south to Texas east to Florida (FNA 1997). It also occurs as an introduced species to most of New England (Native Plant Trust 2024), and elsewhere in Canada and the western United States. Range extent was estimated to be over 4 million square kilometers using herbarium specimens and photo-based observations documented between 2021 and 2024 (GBIF 2024, iNaturalist 2024, SEINet 2024).
Occurrences CommentsBy applying a 1 km separation distance to herbarium specimens and photo-based observations documented between 2021 and 2024, it is estimated that there are thousands of occurrences rangewide (GBIF 2024, iNaturalist 2024, SEINet 2024). However, this taxon is commonly cultivated, and iNaturalist observations (>50,000) were not evaluated for evidence of cultivation (iNaturalist 2024).
Threat Impact CommentsNative populations of Juglans nigra are primarily threatened by over-harvest, as wood has been heavily prized for furniture making and gunstocks (Williams et al. 1990). The top causes of death for black walnut recorded range-wide between 2005 and 2010 were unknown (38.1%), vegetation (28.5%), and silviculture or land clearing activities (9.6%) (Randolph et al. 2013). Additional potential threats include damage by defoliating insects, fungal diseases (including thousand cankers disease), wildfire, succession, wind disturbance, drought, predation, and other threats in some places.