Ash Tree Guide: All 12 Species, Colors, Types, Identification (& Disease)

Image Credit: Ramon Perucho (rperucho)²¹

These trees are an essential part of North American forests. They provide food and habitat for birds, insects, and squirrels and support vital pollinator species like moths and butterflies. The decline of these species will gravely affect 80% of the trees and change the composition of urban and wild forests.

The fast-moving and destructive Emerald Ash Borer beetle is destroying tens of millions of ash trees left behind by the ash tree disease, worsening an already grave predicament. Due to global warming, very cold areas for the beetle are currently suitable for it, making it hard to know the extent of its infestation in the future.²

How To Identify Ash Trees: What Should You Look At?

The tree is easy to identify since, when mature, they reach a height of 30 meters. Graceful and tall, they usually grow together, forming a domed canopy. The tree is identifiable in winter by its distinctive smooth twigs that look black.

Ash Tree Leaves

The leaves are pinnately compound, comprising roughly 3 to 6 opposite pairs of oval and light green leaflets with tips measuring 40cm with an extra single terminal leaflet at the end. Its leaves can follow the direction of the sunlight, and in some cases, the whole tree crown may lean in the sun’s orientation. These leaves fall when they are still green.

Ash Tree Flowers

Ash trees are dioecious, meaning that female and male flowers grow on different trees, although a tree can also have both on different branches. Both female and male flowers are purple and appear before their leaves in spring. Its flowers grow in clusters at the end of the twigs.

Ash Tree Fruits

Once the wind has aided in the pollination of the female flowers, they develop into noticeable ‘keys,’ or winged fruits in autumn and summer. In early spring and winter, they detach and fall from the twig, and mammals and birds disperse them.

Ash Tree Habitat

Ash does well in fertile, well-drained, and deep soil in cool environments. It is a native⁵ of Africa, Asia Minor, and Europe and is also found in North America. It is the third most common tree in Great Britain.

Ash Tree Bark

Ash is a smooth-grained colored hardwood. Its distinctive beige-to-light-brown and straight-grain color make it an attractive option for exquisite furniture. It is among the most durable wood varieties and has a long furniture-making history.

The wood is aesthetically pleasing, lightweight, durable, and perfectly absorbs wood stains. Its trait of being shock-resistant and lightweight makes it a favorite for tool handles, restaurant furniture, and baseball bats.

Ash Tree Types and Varieties: What Are They?

There are a number of varieties of Ash Trees, some of the common to North America and other continents, include the following.

Its thick gray bark becomes scaly and fissured as it matures and ages. This tree has 7 to 13 leaflets in its compound leaf group. And its leaves turn yellow during fall.

Professionals don’t recommend cultivating it since it is the most devastating ash species by emerald ash borer and ash tree disease. It is a native of the northeastern US and eastern Canada and grows 50 to 80 feet tall.³

Its medium-green leaves turn into different shades of yellow in fall and include 5 to 9 leaflets. Red Ash is planted as a shade tree, and it grows to a height of 50 to 70 feet. The species is native to northern and eastern North America.³

As it ages, it develops into a fully rounded crown that resembles a pyramid, and its gray bark develops a diamond-shaped ridges pattern as it matures.³ The leaves are whitish-green on the underside and dark green on top and form clusters of 5 to 9 leaflets and turn purplish yellow in fall.

A differentiating trait of the species is the square shape of the shoots. The leaves of this tree form clusters of 7-11 leaflets and turn dull yellow and gray in fall. When mature, its gray bark⁶ forms an irregular plate.³

Though it does well in medium to wet locations, it is best for dry places. Traditionally used as a street tree, the tree is considered to have a higher chance of surviving the emerald ash borer. It is native to the Midwestern United States and grows to 50 to 75 feet.

While young, it displays a smooth, light-gray bark that turns more textural, darker, and rougher as the tree ages. It provides a great shade and grows to 30 to 40 feet and is a native of southwestern United States.

When young, it is oval or upright. Its dark green and lustrous leaves create a light shade under the canopy, making it a good lawn experimental tree.

The leaves of the tree turn into shades of red to purple before autumn.

Ash Tree Diseases: Invasive Species Borer Beetle, What is It?

Emerald ash borer is an invasive beetle pest of the ash trees. It is a member of Buprestidae, a beetle family, and damages trees leading to their death.¹

(Image: Erik Karits¹³)

Emerald ash borer is native to the Russian Far East, Japan, China, Mongolia, Korea, and Taiwan. Research in 2002 discovered that the pest is responsible for the destruction and deaths of ash trees in the United States. Adult borer beetles⁷ are slender, elongated, and metallic-emerald green.¹

How to Grow Ash Trees: What You Should Do?

Pick a location with full sunlight, 40-60 or more inches away from other structures, to prevent ash tree roots and branches from causing problems. Ensure that the soil pH is between 4 and 7, then dig a hole double the width of the root ball and one foot in depth.⁴

(Blue Ash Image: Matt Berger²² and Carolina Ash Image: Siddarth Machado²³)

Proceed to gently firm the soil around the roots, then excavate a small moat around the tree’s base, but don’t damage the roots, and fill the moat with water. Ensure that you prune and water it.

Folklore, Significance, and Medicinal Qualities of Ash Trees

The tree was thought to have mystical and medicinal properties, and its wood was exhumed to keep off evil spirits. According to Norse mythology, Ash was the ‘Tree of Life, and the first human on earth came from the tree. It is still referred to as the ‘Venus of the Woods.’

The druids regarded its ashes as sacred in Britain, and their wands were made of it.

Today, its young, green, and immature seeds are eaten and used as medicinal herbs.

How Much Carbon Do Ash Trees Sequester? Is it Enough?

An ash tree sequesters roughly 25 kilograms of carbon dioxide annually. Each cubic meter of wood absorbs less than 1 ton of carbon monoxide per year. By the time it reaches 40 years, it will have absorbed 1 ton of carbon monoxide.

In order to save them, the Ash tree must be protected from emerald ash borer beetles and ash tree disease to preserve them from extinction, and governments, organizations, and individuals should work together to achieve this.

Frequently Asked Questions About Ash Tree