Common Name: Oregon Ash

General Information

Fraxinus latifolia is a deciduous tree that can grow up to 22 metres tall[].
The plant is harvested from the wild for local use as a medicine and source of wood. The wood is also harvested on a commercial basis. The plant is sometimes grown as an ornamental and a street tree.
Fraxinus latifolia is widespread and common in the US, but it faces a major potential threat in the form of the Emerald Ash Borer, to which this species has been shown to be susceptible. Fraxinus latifolia has a more temperate distribution than some of the other western Fraxinus species in the US, and is therefore more likely to be affected and susceptible to severe declines caused by this pest. The species also threatened by its widespread use as a timber. Population decline in the next 100 years may reach nearly 30%, therefore the plant is classified as 'Near Threatened' in the IUCN Red List of Threatened Species(2013)[].

Known Hazards

None known

Botanical References

, ,

Range

Western N. America - British Colombia, Washington, Oregon California.

Habitat

Rather deep, fertile, usually moist soils in the neighbourhood of streams near the coast[, ]. Wooded wetlands, lake shores, and in riparian habitats; at elevations up to 1,520 metres[].

Properties

Conservation Status	Near Threatened
Medicinal Rating
Other Uses Rating
Habit	Deciduous Tree
Height	20.00 m
Pollinators	Wind
Self-fertile	No
Cultivation Status	Wild

Cultivation Details

Fraxinus latifolia is a moderately cold-hardy plant, able to tolerate temperatures down to around -20°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[, ]. Plants succeed when growing in exposed positions[] and also in alkaline soils[]. They tolerate atmospheric pollution[].
The plant begins producing seed at about 30 years of age[].
A fast growing tree for its first 75 years in the wild, it then grows slowly reaching a maximum age of 250 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[].
This species is closely related to Fraxinus pennsylvanica[].
A dioecious species - both male and female forms must be grown if fruit and seed are required.

Edible Uses

None known

Medicinal

The pulverised fresh roots were used by some native North American Indian tribes to treat serious wounds[, ].
A cold infusion of the twigs has been used to treat fevers[].

The bark is anthelmintic[].

Agroforestry Uses:

A fairly wind resistant tree, it can be grown as part of a shelterbelt planting[].
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

Wood - hard, brittle, light, coarse grained. A valuable timber tree, it is largely used for making furniture, the interiors of buildings, cooperage etc[, , , ].
The wood is used as a fuel[, , , ]. An excellent fuel, it splits easily and has a high calorific value[].

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.