Common Name: Blue Ash

General Information

Fraxinus quadrangulata is a deciduous tree that usually grows up to 20 metres tall, occasionally reaching 30 metres or more[].
The plant is harvested from the wild for its valuable wood, which is used locally and also traded[].. It has often been grown as an ornamental.
Fraxinus quadrangulata is suffering the devastating impact of a recently introduced invasive pest, the Emerald Ash Borer, that has rapidly spread across much of its native range and shows no sign of stopping. The disease causes virtually 100% fatality and regeneration is almost non-existent. A population decline of at least 80% over the next 100 years (and likely much faster than that) is assumed. The plant is classified as 'Critically Endangered' in the IUCN Red List of Threatened Species(2017)[].

Known Hazards

None known

Botanical References

, ,

Range

Central and eastern N. America - Ontario south to Kansas, Oklaoma and Georgia

Habitat

Dry or moist rich woods[], especially on limestone hills[]. Upland forests on dry, rocky habitats, in limestone glades and on limestone bluffs, thriving on alkaline soils[].

Properties

Conservation Status	Critically Endangered
Other Uses Rating
Habit	Deciduous Tree
Height	20.00 m
Pollinators	Wind
Cultivation Status	Wild

Cultivation Details

Fraxinus quadrangulata is a very cold-hardy plant, able to tolerate temperatures down to around -30°c when fully dormant[].
Prefers a deep loamy soil, even if it is on the heavy side[, ]. Most members of this genus are gross feeders and require a rich soil[, ]. Succeeding on dry soils, this species is one of the more drought tolerant of the ashes[]. Plants succeed when growing in exposed positions[] and also in alkaline soils[]. They tolerate atmospheric pollution[].
A fast-growing tree in the wild, where it lives 125 - 150 years[].
A recently introduced invasive pest, the Emerald Ash Borer has rapidly spread across much of N. America and is devastating the genus Fraxinus. The borer infests and feeds on all the North American ash species it has so far encountered. The nature of the infestation (larval feeding in the phloem) effectively girdles trees as small as 25mm in diameter, which is many years before reproductive maturity, leading to death within five years of infestation. The borer therefore causes virtually 100% mortality of Ash populations. The Ash species are unable to persist for very long through vegetative reproduction, and seeds only remain viable in the soilfor at most 7 - 8 years, so regeneration after borer infestation is minimal or nonexistent. Furthermore, the borer persists in forests in low population densities after major ash population crashes, so the orphaned cohort of ash seedlings that remains is quickly infested as they reach a suitable size[].
Most species in this genus are dioecious but this species is said to be hermaphrodite[, ].

Edible Uses

None known

Medicinal

None known

Agroforestry Uses:

Fraxinus species in general are gross feeders with an extensive, fibrous root system, which makes transplanting easy, but means that other species will often not grow well if planted nearby, especially if they are shallow rooted[],

Other Uses

A blue dye is obtained from the inner bark[, , ]. The bark is ground into a powder and then steeped in water in order to obtain the dye[].

The wood is hard, heavy, close-grained, durable, but not strong and is somewhat brittle. It weighs 47lb per cubic foot. The wood is largely used for flooring, the interior finishes of houses, construction etc[, , , , , ].

The wood is strong and of good quality for uses like tool handles and furniture[].

Propagation

The seed is best harvested green - as soon as it is fully developed but before it has fully dried on the tree - and can then be sown immediately in a cold frame[]. It usually germinates in the spring[]. Stored seed requires a period of cold stratification and is best sown as soon as possible in a cold frame[]. Prick out the seedlings into individual pots when they are large enough to handle and grow them on in a cold frame for their first winter. Plant them out into their permanent positions or a nursery bed in late spring or early summer of the following year.
If you have sufficient seed then it is possible to sow it directly into an outdoor seedbed, preferably in the autumn. Grow the seedlings on in the seedbed for 2 years before transplanting either to their permanent positions or to nursery beds.