ASH TREE
IDENTIFICATION
GUIDE

David L. Roberts, Ph.D.
Michigan State University Extension

ash tree branches
 ASH  TREE  BRANCHES     7/2003

Welcome

               Ash Identification Guide:
Ash trees (Fraxinus species) are easily identified if several simple factors are understood. Ash is unique from other trees because of the following distinctive characteristics: opposite branching and compound leaf according to the following descriptions of pictures. Remember, mountain ash (Sorbus) is not a true ash (Fraxinus), and is not affected by the Emerald Ash Borer.
Opposite Branching - MAD Horse:
Very few trees in our landscapes and forests have opposite branching. The predominant types are Maple, Ash, Dogwood and Horsechestnut. A simple phrase to remember when identifying trees with opposite branching is to use the acronym *MAD Horse* representing  Maple,  Ash,  Dogwood &  Horsechestnut.  When looking for opposite branching in trees, please consider that buds or limbs may die; hence not every single branch will have an opposite mate.
 
opposing branches opposing brances II
  Red dots mark opposing branches   Underneath side of another branch
opposing branches III opposing branch winter
 Another example of opposing branches   A fall skeleton of an ash branch.

Compound Leaf:
A simple leaf is a single leaf defined by having a bud at the base of the leaf stem (also known as a petiole).
A compound leaf is one that has more than one leaflet while the entire leaf, as defined, has a bud at its stem base (petiole). Ash typically have approximately 5-9 leaflets per leaf.

 
young ash leaf ash leaf green ash leaf
 Very young ash leaf with adult EAB.    Ash   One leaf, 9 leaflets  Green Ash One leaf, 7 leaflets
ash leaf II black ash leaf white ash leaf
  Ash  One leaf, 9 leaflets   Black Ash One leaf, 7 leaflets  White Ash top/bottom One leaf, 7 leaflets
box elder branch

 Box Elder - Branches with 3 leaves shown; each having 3 leaflets. Same as Maple leaves.

Following are leaves of Maple, Ash, and Dogwood, which have opposite branching (MAD Horse)
maple leaf
ash leaf III
dogwood leaves
Maple - one leaf Ash - one leaf with 9 leaflets Dogwood - 6 leaves on branch


Seeds and bark of ash are also unique.  Some older ash trees have a characteristic diamond pattern to their bark.

 
healthy ash leaves on branch

A close-up of a healthy ash branch with seeds!

ash tree trunk
 
Nice details on this mature ash trunk and branches

 
young ash bark green ash bark mature ash bark
 The bark on a younger ash tree is relatively smooth.  Green ash - As the tree ages the bark thickens and a diamond-like pattern in the raised bark is noticeable.   This ridged trunk section is from a very mature ash tree.

               Following are leaves from trees that may look like ash but have alternate branching:
 

hickory leaf hophornbeam leaves walnut leaf
       Hickory - One leaf with 5 leaflets  Hophornbeam -Many leaves on branch  Walnut - One leaf with many leaflets

OTHER WEB RESOURCES:

  Jackson Extension site has more on Ash Tree ID information
  MSU Hort. Suggested Trees for Lower Michigan   
  Alternative Selections for Problems in Tree Species .pdf
  Fraxinus - Ash  Ohio State University Bulletin - Great details here
  White Ash Identification
  Green Ash Identification
  Ash Trees Leaves/Bark/Twigs - Iowa State University Ext.

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ash leaf    David L. Roberts, Ph.D.
   Michigan State University Extension Southeast
   28115 Meadowbrook Rd., Novi, MI  48377-3128 
 Campus: 
    Michigan State University
    B17 Plant & Soil Sciences
    East Lansing, MI  48824-1359
   For comments or questions email:  robertsd@msu.edu

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