Fraxinus americana

2015-10-21 10 57 30 White Ash foliage during autumn along Pennington Road (New Jersey Route 31) in Ewing, New Jersey

Fraxinus americana (Oleaceae)

White Ash Leaves

Fraxinus americana, commonly known as the white ash, is a species of ash tree native to eastern and central North America. It is found from Nova Scotia west to Minnesota, south to northern Florida, and southwest to eastern Texas. Valued for its timber, the white ash is also known for its distinctive appearance, with deep green leaves that turn purple to deep red in the autumn, making it a popular choice in landscaping and urban forestry.

Description

Fraxinus americana is a deciduous tree that typically grows to a height of 20–25 m (65–82 ft), with a trunk diameter of up to 60 cm (24 in). The tree's bark is gray and deeply furrowed, forming a diamond pattern. The leaves are opposite, pinnately compound, with 5–9 leaflets that are dark green above and paler below. Each leaflet is ovate and 5–12 cm long. The species is dioecious, with male and female flowers appearing on separate trees in spring. The fruit is a samara, 2.5–5 cm long, comprising a single seed with a long, thin wing.

Ecology

White ash prefers rich, moist, well-drained soils and is commonly found in mixed hardwood forests. It is a climax species, meaning it is one of the last species to dominate in a mature forest. The tree provides habitat and food for various wildlife species. Birds and small mammals often eat the seeds, while the foliage serves as food for butterfly larvae.

The species has been threatened by the Emerald Ash Borer (Agrilus planipennis), an invasive beetle that has killed millions of ash trees in North America. Efforts to control the beetle and save the white ash include insecticides, tree removal, and breeding programs for resistance.

Uses

Historically, Fraxinus americana has been a significant source of hardwood timber, prized for its strength, elasticity, and light weight. It is commonly used for furniture, flooring, baseball bats, and other sporting goods. The wood is also favored for tool handles because of its ability to absorb shock without splintering.

In landscaping, white ash is appreciated for its fast growth, attractive fall foliage, and relatively low maintenance requirements. However, due to the threat of the Emerald Ash Borer, its use is now more restricted, with recommendations to plant alternative species that are not susceptible to the beetle.

Conservation

Conservation efforts for Fraxinus americana focus on research into resistance against the Emerald Ash Borer, public education on preventing the spread of the beetle, and the promotion of biodiversity by planting a variety of tree species. These efforts aim to preserve the white ash as a valuable component of North American forests and urban landscapes.

See Also

• Ash Tree
• Emerald Ash Borer
• Deciduous Trees
• Forestry in North America