Mar 15, 20233 min read

Guide to Identifying the Ash Tree - A Morel Favorite 🍄

Updated: Mar 17, 2023

'Tis the season for scouting Morel mushrooms! Do you know how to recognize an Ash tree?

Fraxinus americanus "White Ash"

With the start of Morel Mushroom season, this is definitely one of the trees you'll want to be able to recognize for scouting out spots to forage! 🧠 The tricky part is the leaves - they're just barely budding on these babies this time of year, so use this guide to identify various other characteristics first.

The genus Fraxinus is home to over 60 species of trees and belongs to the Oleaceae family, along with olives and lilacs (Wiki). For morel hunting purposes here in the southeastern US, we'll be focusing specifically on the White Ash tree, native to central and eastern North America.

If you've heard anything about Ash Trees it most-likely has to do with their nemesis, the Emerald Ash Borer (EAB), a green beetle native to Asia that's been single-handedly wiping out Ash trees 😞 and they're not picky; The EAB has been threatening the entire Fraxinus genus ever since its introduction into the US in the 1990s (Wiki). These invasive beetles have been absolutely devastating to the Ash trees in particular, including White Ash, Green Ash, and the Black Ash which is known as a keystone species.

But something we know about morels is they do love a dying tree... 🫤 In fact, the two patches of Morels we've found while traveling were both beneath White Ash trees. The first patch was in Oklahoma at the base of a mature White Ash on a slope leading down to a lake. We knew the Ash was dying because it had a large dead limb that had recently fallen. Large sections of bark had peeled off the trunk, exposing the beetle's larval tracks along the cambium layer (as shown in photo below). So we were sad to see such a large, beautiful White Ash slowly meet it's demise, but happy to find 4 plump Yellow Morels at its base. Ahh, life is a balance...

So unfortunately a lot of the Ash you'll run into will be dead or dying, although that can be a helpful aid in finding these trees during morel season, by looking out for fallen limbs, peeling bark, and signs of the EAB.

We do encourage everyone help Ash trees by educating ourselves about the EAB infestation and how to recognize it, as well as taking the time to report any new/notable sightings. The Emerald Ash Borer beetle has been found in 35 states in the US already and that detailed map can be found here.

So without further ado, let's identify some White Ash tree characteristics, shall we?!

Shape: In an open areas a mature Ash will grow into a round-topped shape (picture the emoji tree 🌳 ) while in forested areas with thicker canopies the crown will develop a more narrow or pyramidal shape. Note in the photos how the tree on the left with more sunlight sports a lower limb and more branching than the tree on the right in a thicker forest.

Bark: Typically a light yellow-brown to light gray color. When young in most sections the bark resembles a tight square-like pattern and with age develops more triangular pointed ridges with furrows in "X" patterns along the trunk, sometimes referred to as diamond-shaped or net-like patterns. Typically a mature tree will show these two patterns alternating in sections along the trunk. A dead or dying White Ash tree's bark will lighten to a chalky gray, almost white (see top two photos).

Leaves / Leaflets: Known for their pale underside (hence the name "White Ash") the shape of each is ovate to lanceolate *aka oval to pointy oval* with opposite arrangement *aka close to symmetrical*. These compound leaves sport leaflets of 5-9, most typically 7. In the fall the leaves can turn a variety of colors from yellow to orange to a deep red or maroon.