White ash (Fraxinus americana): 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 americana L., olive family
Other names	Biltmore ash and Biltmore white ash (Silvics); American white ash (Wood Handbook)
Native status, USDA PLANTS	Native in Canada and in the lower 48 states; listed as introduced in Hawaii
Size, Silvics	Grows to medium size on rich, moist, well-drained soils; trees in unthinned Massachusetts stands averaged 36 cm (14 in) in diameter and 25 m (82 ft) in height at age 60
Green weight of the wood, NRS-38	50 lb per cubic foot, without bark

Native range and sites

The Silvics of North America handbook (Agriculture Handbook 654, volume 2, 1990) calls white ash the most common and useful native ash, though never a dominant species in the forest. It records natural growth from Cape Breton Island, Nova Scotia, to northern Florida in the east, and from eastern Minnesota south to eastern Texas at the western edge. The handbook says the species has demanding soil fertility and moisture needs, met on soils from limestone, basalt, shale, alluvium and fine glacial till. It describes the tree as a minor but constant part of the understory and overstory of mature forests on suitable soils and says it is used in yard, street and roadside plantings and has been planted on strip mines with some success.

Flowers and seed

Silvics says white ash is dioecious, with flowers appearing with or just before the leaves in April and May. Good seed crops come roughly every third year, and about half the flowering trees bear heavily. Almost 99 percent of the winged fruits hold one seed. Vigorous trees may first flower at only 8 to 10 cm (3 to 4 in) in diameter, though the tree is usually 20 to 25 cm (8 to 10 in) across before it flowers abundantly. The winged seeds feed many birds, and the handbook names the wood duck, bobwhite, purple finch, pine grosbeak and fox squirrel.

Growth and roots

The handbook says a field-grown white ash in full sun may take 3 to 15 years to reach 1.5 m (5 ft), after which the root system is usually well established and the tree can grow rapidly even among weeds. For dominant and codominant trees in unthinned, even-aged central Massachusetts stands it gives 10 cm (4 in) in diameter and 12 m (39 ft) in height at age 20, rising to 43 cm (17 in) and 27 m (89 ft) at age 70. It describes the tree as having low shade tolerance yet able to persist for a few years in moderately dense shade and to respond quickly to openings in the canopy.

On roots, Silvics says white ash generally forms a taproot that branches into a few large roots growing downward, with single lateral branches developing at intervals from those, and that grafting between roots of the same species is common. Root distribution is strongly influenced by soil type. Stumps of freshly cut seedlings and saplings sprout readily, usually with one or two stems.

Wood

The Wood Handbook (FPL-GTR-282, 2021) puts American white ash in the white ash group with green ash, blue ash and Oregon ash. It says the heartwood of the group is brown and the sapwood light-colored or nearly white, and that second-growth trees are particularly sought after because their wood is heavy, strong, hard and stiff with high resistance to shock. It lists nonstriking tool handles, oars, baseball bats and other sporting and athletic goods as the principal uses of American white ash. Silvics also describes the wood as tough, strong and highly resistant to shock.

Wood Handbook figure	Green	At 12% moisture content
Specific gravity (Table 5-3b)	0.55	0.60
Modulus of rupture, lbf per square inch (Table 5-3b)	9,500	15,400
Side hardness, lbf (Table 5-3b)	960	1,320
Moisture content of green wood, percent (Table 4-1)	46 heartwood, 44 sapwood	Not applicable

The green weight of the wood is in the NRS-38 table, the same figure used in the log weight calculator.

Pests and diseases the sources name

Silvics (1990) names ash decline, also called ash dieback, as the most serious problem affecting white ash, a disease complex recorded from the Great Plains to the Atlantic coast between 39 and 45 degrees north latitude. It says ash yellows, caused by mycoplasma-like organisms, has been found with most of the dying trees where decline is conspicuous, but that because not all dying trees are infected the decline is thought to result from multiple causes. It names these agents by the names it used.

Fungi and cankers. Drought-weakened trees may be invaded by canker-causing fungi (Fusicoccum and Cytophoma pruinosa). Leaf spot fungi and anthracnose cause premature defoliation, a rust distorts petioles and twigs, and Nectria galligena cankers may break branches.
Heart rots. Perenniporia fraxinophilus, Phellinus igniarius, Pleurotus ostreatus, Tyromyces spraguei and Laetiporus sulphureus, which the handbook says enter through wounds or broken branches, mainly on older trees.
Scale. Oystershell scale, called the most serious insect pest, and cottony maple scale.
Defoliators. Ash sawflies, forest tent caterpillar, green fruitworm and several moths.
Borers. The ash borer, which it says may seriously damage young shade and shelterbelt trees, the ash and privet borer, and the red-headed and banded ash borers, which colonize cut logs and dead or dying trees.
Other. Air pollution, with the species rated sensitive to ozone, and browsing by deer and cattle on seedlings.

The 1990 handbook does not name the emerald ash borer. The Wood Handbook says American white ash, green ash and blue ash, like black ash, are considered by the International Union for Conservation of Nature to be critically endangered because of that insect. The guide on emerald ash borer rules by country gives each agency's wording, ash dieback rules gives the British agencies' wording on the separate fungal disease called ash dieback there, and reporting a pest in the United States gives the office that takes sightings of regulated pests. Who may apply pesticides is in pesticide licences by country.