Tree Tuesday: White Ash

White ash (Fraxinus americana) grows over most of eastern North America but has been declining for several years due to multiple environmental and insect threats. Ash decline (or “ash dieback” or “ash yellows”) is the most serious problem affecting white ash. The decline is especially prevalent in New York, Pennsylvania and Vermont. Ash decline is caused by Mycoplasma-like organisms (MLO).

Emerald ash borer (EAB)

The other major threat is the Emerald ash borer (EAB), an exotic beetle whose larvae (the immature stage) feed on the inner bark of ash trees, disrupting the tree’s ability to transport water and nutrients.

Girdled ash trees are an effective detection tool for emerald ash borer.
Ash tree infected with Emerald Ash Borer. Notice the holes and larva tracks in the cambium.

The wood of white ash is valued for its strength, hardness, heavy weight, and elasticity. Native Americans appreciated its usefulness for tools and implements, and it is used extensively today for tool handles. Ash is famously used in wooden baseball bats.

The ash tree has an opposite twig pattern, compound leaf and a distinctive bark patten referred to as diamond pattern or herringbone.

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