American Hornbeam (Carpinus caroliniana) Leaves in Winter

Deciduous trees that hold onto their leaves throughout the winter are called 'marcescent'. In autumn, the leaves of most deciduous trees develop an abscission layer where the petiole meets the branch, which allows the leaves to fall off without creating a wound on the stem. But, dry leaves will stay on marcescent trees because the leaves didn’t develop that abscission layer.

Marcescence is usually a juvenile trait that may disappear as the tree matures. It doesn't always affect the entire tree, but you may see leaves persisting only on a few branches. Weather can also play a role in marcescence. Early freezes may kill the leaves before they have time to develop an abscission layer, resulting in brown leaves on trees that aren’t usually marcescent.

American Beech (Fagus grandifolia), Oak (Quercus sp.), and American Hornbeam (Carpinus caroliniana) sometimes exhibit marcescence.

Habitat: Mixed forest