Lingering Leaves: The American Beech Tree and the Process of Marcescence

Nature always surprises and delights. As soon as I think I have it figured out, a new discovery shows just how much more I need to learn.

Take the beautiful American beech (Fagus grandifolia), a tree gracing the hardwood forests blanketing the mountains around my childhood home in southern West Virginia. During my frequent solitary hikes, I couldn’t resist walking up to a beech to admire its smooth gray bark, which contrasted with the furrowed barks of the various oaks and hickories dominating the southern Appalachian forests.

Most dendrologists – tree scientists – describe the tree as long-lived, hardy, healthy, and strong; traits we attribute to the label “American.” For me, it’s as American in character and personality as anything can be.

The American beech is not the tallest tree in the forest, but it is certainly a most graceful one with its distinctive smooth bark and in autumn, an eloquent coat of bronze leaves. And what about those branches? From its thick, muscular boughs to the hundreds of branches that further divide into thousands of branchlets, I doubt any other eastern hardwood forest tree can compare.

In the Piedmont ecosystem of northern Virginia where I now reside, the American beech tree is common, primarily on drier sites of mesic (moist) soils. The beech dominates as a sub-canopy tree, but as a major canopy tree it yields to the more aggressive species of maples, oaks, and hickories.

The lower leaves are shown in the understory of American beech at Banshee Reeks Nature Preserve in late winter

The lower leaves are shown in the understory of American beech at Banshee Reeks Nature Preserve in late winter

At Banshee Reeks Nature Preserve in Loudoun County, Virginia – the place where I do most of my local photography – the American beech is a common forest tree. Over the years, I began to notice how the lower leaves of the beech tree stayed on the limbs long after the other forest trees had shed theirs. The beech tree retains its leaves long past the winter months, often lingering into the early spring season. But why? What advantage does it have by doing this?

The American beech tree along with a few other species such as scarlet and pin oaks have leaves classified as marcescent, which means the leaves wither but do not detach from the branches. For the American beech, these marcescent leaves occur on younger trees and on the lower branches of older trees.

American Beech trees and their marcescence leaves in late winter

American Beech trees and their marcescence leaves in late winter

Scientists believe beech trees it may discourage deer and other herbivores from feeding on the tree’s twigs and buds, which are a nutritious high-energy food source. The dried, faded leaves are much lower in nutrients and not as tasty, so one bite might be enough for deer to look elsewhere for food.American beech tree leaves in late winter

As spring emerges and more succulent forbs and herbs become available, deer focus their attention away from the beech tree. The tree then completes the final process of shedding its leaves, which by this time are nearly transparent due to the bleaching from constant exposure to the sun’s ultraviolet rays.

Nature is a never-ending teacher – an instructor for life, and for us to be its students only require us to be curious enough to want to learn more.

I have more to share with you about this most beautiful tree. So stay tuned for part two of my discovery of the American beech tree.

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