American Beech Trees
Beautiful and in Trouble



American beech trees.

One of the dominant canopy species of the northern hardwood forest found at all but the highest elevations.

It is one of the most shade tolerant hardwood species in the forest, and therefore, had increased its presence in the canopy as forests matured since logging in the late 19Th and early 20Th centuries.

These trees play and played a big role in feeding animals and people with their little fruits called beechnuts.

They were a tree of my childhood in Allegan county, Michigan.

They make great climbing trees, trees for forts and the smooth barked trees always made way for the pocket knife and carving names and stuff like hearts and initials into a trunk or large branch (yes I am guilty).

Until recently that is.

American beech is a tree in trouble.

Slowly and methodically, our trees are under attack.

Beech Bark Disease

Once again, a foreign invader is attacking.

Beech bark disease causes significant mortality and defects in American beech ( Fagus grandifolia).

The disease results when bark, attacked and altered by the beech scale, Cryptococcus fagisuga, is invaded and killed by fungi, primarily Nectria coccinea

Accounts from Europe indicate that the disease was killing European beech (Fagus sylvatica) before 1849.

The scale insect, readily visible on the trees, was considered the cause of death until 1914, when it was learned, that a fungus infected trees infested by the scale.

Beech bark disease first arrived in North America around 1890 in Nova Scotia.

By 1932 it was present in Maine, and by the the 1970s it had swept through much of the New England area and is now infecting trees in Michigan and the Great Lakes Region.

Typically BBD has spread rapidly through an area with an "advancing front" of the scale insect, followed by a "killing front" of heavy infestations of the scale insect and nectria fungus.

Within the killing front many of the larger Beech trees will die or be left in a weakened state.

Because the scale insect doesn't fly like Emerald Ash Borer and others, the advance is slow.

The extremely smooth bark of small young Beech trees is less susceptible to infestation by the scale insect, so these trees often remain healthy.

In the wake of these fronts is left an "aftermath zone", where populations of both the scale insect and the nectria fungus remain in reduced numbers.

Although less active, BBD remains in the forest, infecting individual trees as they grow large enough to become inviting to the scale insect.

These photos to the right and below show varying degrees of beech bark disease (BBD).



It is sad knowing these beautiful American Beech Trees will probably perish to BBD one day.

The first photo above and to your right, shows normal beech bark which is very smooth, even on very large trees.

The second photo shows isolated "cankers".

The disease is a pathogen complex involving a scale insect and a nectria fungus. The insect pierces the bark to feed, creating a place for the fungus to enter at a later date.

The fungus begins to grow within the bark, resulting in the round scars.

The last photo is of bark severely affected by the disease, where individual "cankers" have grown together indicating that the fungus has spread completely around the bole.

Fungal activity interrupts the tree's normal physiological processes, and a severely infected tree will most likely die.

Trees that do not die will remain weak and become more susceptible to wind damage.

Another story about an introduced species.

This one is slowly taking away one of our most prized trees.

Return to the Top of Beech Trees

Ash Trees and Emerald Ash Borer

Return to Trees of the Northeast and Great Lakes


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