Simple ways to identify ash trees

Opposite branching

emerald-ash-borer-opposite-branching-horizontal

By opposite branching, we mean the branches protruding from tree limbs have a mate protruding from the exact opposite side of the same limb. Only ash, maple, dogwood and horse chestnut trees have opposite branching.

Compound leaves

Ash leaves typically have 5-9 leaflets per compound leaf

A simple leaf is defined as a single leaf that has a bud at the base of the leaf stem. Conversely, a compound leaf (the sort you’re looking for) is defined as having more than one leaflet per leaf connecting to a stem that has a bud at its base. Ash tree leaves typically have 5-9 leaflets per leaf.

Diamond-pattern bark

White ash tree bark with diamond pattern

While this identification method may not be as helpful when it comes to young ash trees (they typically have smoother bark), the bark on more advanced ash trees tends to have distinct diamond patterns.

Is the EAB a threat to my ash?

Yes. The emerald ash borer (EAB) is a threat to all trees in the genus fraxinus classification, which is more typically known as the common ash tree. What do we mean by common ash? If you own one in Denver, chances are it’s of the green (Fraxinus pennsylvanica) or white (Fraxinus americana) variety. The EAB is a threat to both. It’s also a threat to the black, blue and even autumn purple ashes. In other words, if you have an ash tree, it’s time to start planning your defense.

White Ash
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White ash

Green-ash-tree-bark

HELP US MAP OUR ASHES

Your friendly City Forester has mapped each and every one of the public ash trees in Denver. Feel like you missed out on the fun? Well you’re in luck! Now you can join the tree mapping party thanks to an app called Curio.

In many ways, Curio serves as a social network for trees. It gives their human companions the ability to tag a tree on an interactive map, add stories, photos and data about a favorite tree, search for trees within the app and even add tree-based missions for you and your friends to conquer.

Not only are they a lot of fun, apps like Curio also allow us to protect our urban tree canopies through the sharing of valuable data. Be A Smart Ash, and get in on the act!

Images courtesy Colorado State Forest Service, Paul Wray (Iowa State University, Bugwood.org) and Richard Webb (Bugwood.org )