Common Name: White Ash

General Information

Fraxinus americana is a deciduous tree with a spreading crown; it can grow up to 35 metres tall. The bole of larger trees can be 150 - 180cm in diameter[, ].
One of the most valuable hardwood timber trees in N. America[], whilst also having medicinal uses, It has been used in shelterbelt plantings.
Fraxinus americana is the most common and useful native ash of the US but is suffering the devastating impact of a recently introduced invasive pest, the Emerald Ash Borer, that has rapidly spread across much of the tree's native range of White Ash and shows no sign of stopping. The pest causes virtually 100% mortality of White Ash populations. Current research shows that the overwhelming majority of ash populations will very quickly be overcome by this infestation. As such, a population decline of at least 80% over the next 100 years (and likely much faster than that) is assumed. Therefore the plant is classified as 'Critically Endangered' in the IUCN Red List of Threatened Species(2017)[].

Known Hazards

None known

Botanical References

, ,

Range

Eastern and central N. America - Ontario to Quebec, south to Colorado, Texas and Florida

Habitat

Rich upland to lowland woods[, ]. Usually found in association with other hardwood trees in well-drained soils on slopes; at elevations up to 1,050 metres[, ].

Properties

Conservation Status	Critically Endangered
Edibility Rating
Medicinal Rating
Other Uses Rating
Habit	Deciduous Tree
Height	25.00 m
Growth Rate	Fast
Pollinators	Wind
Self-fertile	No
Cultivation Status	Wild

Cultivation Details

Fraxinus americana is a very cold-hardy plant, able to tolerate temperatures down to around -35°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[]. Succeeds in exposed positions[] and in alkaline soils[]. Tolerates atmospheric pollution[]. Young plants tolerate forest shade[].
Saplings grow slowly at first, but the growth rate speeds up over the next 50 years[]. This species is planted on a small scale, mainly in E. Europe, as a timber tree[]. It has the potential as a forestry tree in Britain, succeeding under conditions that are too dry or frosty for the native ash, F. excelsior[].
A very ornamental tree[], it is often confused in cultivation with F. pennsylvanica[].
Fraxinus americana is suffering the devastating impact of a recently introduced invasive pest, the Emerald Ash Borer, that has rapidly spread across much of the tree's native range and shows no sign of stopping. The pest infests and feeds on all 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 at breast height, which is many years before reproductive maturity. Trees die within five years of infestation. The Emerald Ash Borer causes virtually 100% mortality of White Ash populations, the tree is unable to persist for very long through vegetative reproduction, and seeds only remain viable in the seed bank for 2-3 (rarely 7-8) years. Regeneration after infestation is therefore minimal or nonexistent. Furthermore, the pest persists in forests in low population densities after major ash population crashes, so the orphaned cohort of White Ash seedlings that remains is quickly infested as they reach a suitable size for infestation. While some studies have indicated that a very small portion of White Ash's native range may fall outside the suitable habitat for the pest, all authors agree that the overwhelming majority of ash populations will very quickly be overcome by the infestation. As such, a population decline of at least 80% over the next 100 years (and likely much faster than that) is assumed[].
A dioecious species - both male and female forms must be grown if fruit and seed are required. Male trees usually flower heavily each year, but female trees only flower heavily every 2 - 3 years[].

Edible Uses

A bitter tasting syrup is drawn from the tree[]. The report gives no more details and does not directly say that the syrup was used as food. It was quite possibly only used medicinally[].

Medicinal

The bark is astringent, emmenagogue and a bitter tonic[, , , ]. An infusion is used to promote menstruation[].
An infusion of the bark has been used as a wash to treat skin sores, itches and vermin on the scalp[, ].

The inner bark is diaphoretic, diuretic, emetic and strongly laxative[]. It is used as a tea to remove bile from the intestines, as a tonic after childbirth and to relieve stomach cramps and fevers[, ].
The inner bark is chewed and applied as a poultice to sores[].

The leaves are used to soothe the itching caused by mosquito bites and bee stings[].

The seeds are thought to be aphrodisiac[].

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

The leaves are said to repel rattlesnakes and have been worn on the feet of people travelling in rattlesnake country[]. There are some doubts over the efficacy of this[].

A yellow dye is obtained from the bark[].

The wood is strong, hard, heavy, tough, elastic, close grained, moderately durable[, , ]. It weighs 41lb per cubic foot, seasons well, takes a good polish and is highly shock resistant[, ]. One of the most valuable of the North American timbers[, ], it is much used for tool handles, hockey sticks, baseball bats, the interior of buildings, musical instruments, furniture, woodenware etc[, , , ].
As a fuel this wood is comparable in quality to such excellent species as oak (Quercus spp) and hickory (Carya spp)[].

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.