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.
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.