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Kentucky Coffeetree (Gymnocladus dioicus)

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Kentucky Coffeetree

Summary

A large tree native to the central to northeastern U.S.

Range - Expand

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Native

This tentative map is based on the FHWA's ERA. This data lacks information on Canada, but also overestimates native ranges, especially around the edges, as this post explains. We have not yet reviewed or fixed this map.

USDA Plants Profile for Gymnocladus dioicus

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Habitat

Found in moist soils in bottomlands, and moister sites in open, rocky woodlands. More common on limestone soils and areas that have been glaciated, but uncommon throughout much of its range. Tolerates both drought and occasional flooding, alkaline soils, and compacted soils.

Requires high-light conditions for establishment, and only persists in the earlier-successional stages of closed-canopy forests. It can persist longer on more open sites.

Life Cycle

Seedpods are large and heavy; most fall close to the tree, although pods falling into water can be carried long distances by water. Some seedpods are retained on the tree in winter, where they may fall on crusted snow and be moved a small distance by wind.

The seedpods are slow to decay and may even remain intact for longer than a year. Seeds exhibit a long dormancy, and may seed bank for a number of years.

Uses

This tree is widely planted, including far outside its native range, where it is valued for its ease of growing and tolerance of a wide range of conditions, including urban conditions.

The seeds have been roasted and used as a coffee substitute, hence the name; it does not contain any caffeine.

The wood has a number of desirable properties, including some decay resistance and good workability, but its availability is limited, and as such it tends to be relatively expensive. Like many other legumes, the wood is highly fluorescent under a blacklight.

This plant is the only member of its genus in North America; two other species occur in east Asia.

The broader Umtiza clade of the Caesalpinioideae subfamily of the bean (Fabaceae) family also contains the two native species honeylocust (Gleditsia triacanthos) and water locust (Gleditsia aquatica), both of which overlap with this species in range, as well as carob tree (Ceratonia siliqua), which has been introduced to southern California and Arizona and does not overlap in range.

Notes

Although most legumes have the ability to fix nitrogen, extracting it from the atmosphere and converting it into a form usable by plants, this tree comes from a lineage that has lost this ability.

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