Black ash (Fraxinus nigra): what the agencies record

This page reports what US federal publications say about one tree. It does not identify trees from descriptions or photos and does not say what should be done with any tree. The family overview, tree species in the agency records, explains the sources and holds the comparison table.

At a glance

Item	What the source records
Scientific name	Fraxinus nigra Marshall in USDA PLANTS, olive family
Other names	Swamp ash, basket ash, brown ash, hoop ash and water ash (Silvics)
Native status, USDA PLANTS	Native in Canada and the lower 48 states
Size, Silvics	A small tree: the largest on record, at Bath, Ohio, is 26.5 m (87 ft) tall and 148 cm (58.3 in) in diameter with a crown spread of 18.3 m (60 ft); more commonly the largest trees reach 18 to 21 m (60 to 70 ft) and 30 to 61 cm (12 to 24 in), and in many forests the largest are only 20 to 25 cm (8 to 10 in)
Growth, Silvics	A relatively slow growth rate; site index at base age 50 years ranges from 15 to 24 m (50 to 80 ft) in northern Wisconsin and Michigan
Shade and roots, Silvics	Classed as intolerant of shade; a shallow and fibrous root system well adapted to high soil moisture
Green weight of the wood, NRS-38	52 lb per cubic foot, without bark

Native range and sites

The Silvics of North America handbook (Agriculture Handbook 654, volume 2, 1990) calls black ash a slow-growing tree of northern swampy woodlands and the only ash native to Newfoundland. It says the range runs from western Newfoundland west to southeastern Manitoba and eastern North Dakota; south to Iowa; east to southern Indiana, Ohio and West Virginia; and north from northern Virginia to Delaware and New Jersey. In the northern part of the range it is found from sea level to the highest elevations, while in the southern part it grows only above 610 m (2,000 ft).

The handbook says black ash typically grows in bogs, along streams or in poorly drained areas that are often seasonally flooded, most commonly on peat and muck soils. It tolerates semistagnant conditions, though for best growth the handbook says the water should be moving so the soil is aerated. It names the tree as an important species of the Black Ash-American Elm-Red Maple forest cover type and a common associate of northern white-cedar.

Flowers and seed

Silvics says black ash is polygamous, with small inconspicuous flowers appearing in May or June at about the same time as, or just before, the leaves. The fruit is an elongated, winged, single-seeded samara borne in clusters, ripening from June to September, with seeds dispersed from July to October. A 25-year seed crop survey of 19 tree species in northeastern Wisconsin found black ash produced good seed crops in 28 percent of the years and poor ones in 68 percent, with the longest poor-crop run of any of the 19 species, 7 years. The seeds show dormancy, which the handbook says moist stratification can overcome.

Uses and wildlife

The handbook says black ash has never been commercially important, so many aspects of the tree are unknown. Its easily split wood has been much used for baskets, which the common names basket ash and hoop ash reflect. Seeds are an important food to game birds, songbirds and small animals, and the twigs and leaves provide browse for deer and moose. The handbook also says deer browse heavily on young black ash, and that if poplars are scarce, beaver will cut down ash between 25 and 51 cm (10 to 20 in) in stump diameter.

Wood

The Wood Handbook (FPL-GTR-282, 2021) groups black ash and pumpkin ash as the black ash group, saying the heartwood is darker brown than American white ash and the sapwood light-colored or nearly white. It says the wood is lighter in weight than the white ash group, with a basic specific gravity of 0.45 to 0.48 against more than 0.50, and names decorative veneer, cabinets, millwork, furniture, cooperage and crates among its principal uses. The white ash group is described on the green ash page. Table 5-3b has a separate black ash row, shown below.

Wood Handbook Table 5-3b	Specific gravity	Modulus of rupture (lbf per square inch)	Side hardness (lbf)
Green	0.45	6,000	520
At 12% moisture content	0.49	12,600	850

The Wood Handbook states that specific gravity is based on oven-dry weight and the volume when green or at 12% moisture content. The green weight of the wood without bark is in the NRS-38 table, the same figure used in the log weight calculator.

Diseases, insects and damage the agencies name

Silvics (1990) says a study of defects in Ontario forest trees concluded that black ash is the most defective of eight deciduous species.

Rots. The fungi most often associated with trunk rot and butt rot of black ash were Stereum murrayi and Armillaria mellea. A spongy white heartwood rot (Polyporus hispidus) enters through wounds and is usually found in the upper trunk; in one Minnesota stand it caused lumber degrade in 5 percent of the trees.
Scale. The oystershell scale occasionally kills reproduction and older trees.
Leaf and bark diseases. Leaf spot, anthracnose, rust and canker cause damage the handbook calls similar to that reported for white ash.
Emerald ash borer. The Wood Handbook says that, because of the spread of the emerald ash borer, black ash and pumpkin ash are both considered critically endangered by the International Union for Conservation of Nature, and that widespread harvesting of both live and dead trees was ongoing in an effort to curtail the problem. The guide on emerald ash borer rules by country gives each agency's wording and the date on its page.

The guide on reporting a pest in the United States and the Canada reporting page give the offices that take sightings of regulated pests. Who may apply pesticides is in pesticide licences by country.