Which trees keep their dried leaves throughout the winter?

Fagus grandifolia

American Beech in winter

A winter walk through a woods in Michigan will reveal deciduous trees holding their dried leaves from last fall. Marcescence is the technical term for plant parts that wither but do not fall off. It can refer to leaves, flowers, or fruit. In deciduous leaves an abscission layer forms at the base of the petiole (leaf stem). In most deciduous leaves the abscission layer hardens on the twig side in the fall, the leaves drop-off, and this layer protects the bud-scar on the twig. In marcescent leaves, the abscission layer does not function until buds break in the spring. Andrew Hipp at The Morton Arboretum explains this in greater detail.

Some species are more marcescent than others. Oaks, Beeches, Hornbeams, and Hop-hornbeams commonly hold their leaves. Younger trees exhibit marcesence more often than mature trees. Stress from drought or disease can cause marcescence in any deciduous species .

The color of the winter leaves is normally distinctive but hard to describe. With a little practice you can learn to identify these trees at a distance. Of course, looking at the shape of the leaf, winter bud, or the bark can confirm your identification.

Fagus grandifolia

American Beech leaves in winter

Marcescent leaves on American Beech (Fagus grandifolia) bleach from tan to a ghostly cream-color during the winter. Looking closely at a twig you will see long buds that confirm the identification.

Ostrya virginiana

Hop-Hornbeam leaves and winter bud

Hop-hornbeam (Ostrya virginiana)  has winter leaves that tend to curl. Once again, with practice the color is distinctive. Blue-beech or Hornbeam (Carpinus caroliniana) is similar to Hop-hornbeam but with lighter brown leaves.

Carpinus caroliniana

Blue-beech winter leaves

Oaks (Quercus spp.), especially the Black Oak group (subg. Erythrobalanus), tend to hold their leaves. Some years ago, when Dr. Warren Wagner was studying Shingle Oak (Quercus imbricaria) we learned to identify the species when we drove by. Shingle Oak leaves are tan or “potato-brown color.” Other oak species have a darker, reddish-brown color. Shingle Oak is Michigan’s only simple-leaved oak. Its leaves look more like bay leaves than what we in the north think a “typical” oak leaf should resemble.

Shingle Oak – L                                                                     Pin Oak – R

It is fun to walk through a winter woodlot and identify the leaf-holding species. In Tenhave Woods, in Royal Oak, you can see where the ridges run through the woods by looking at the location of the Beech trees. Hornbeams ring the low swamp forest. Winter often is the best time to get an overview of an area when you can see farther and having the ability to identify some species from a distance is helpful.

Copyright 2017 by Donald Drife

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Alternate Budded Trees with False Terminal Buds I

False Terminal Buds

False Terminal Buds

A false terminal bud is nothing more than a former leaf bud located at the end of a twig. True terminal buds do not have leaf scars, false terminal buds do. Some authors say that the terminal buds are absent.

 

 

Fagus grandifolia


American Beech

 

American Beech (Fagus grandifolia) has buds 3 to 5 times longer than wide. The buds are two ranked (meaning in two rows) and held almost at right angles to the stem.

 

 

 

Gymnocladus dioicus

Kentucky Coffeetree

Kentucky Coffeetree (Gymnocladus dioicus) is a rare native tree in southern Michigan. The twigs are stout, each large bud scar has two buds and normally 5 bundle scars but 3 or 4 bundle scars are seen. Most trees will have a few seedpods that look like dark brown peapods (it is in the Fabaceae, Pea Family).

Platanus occidentialis

Sycamore

 

Sycamore (Platanus occidentalis) is found in floodplains in southern Michigan. The mottled bark is distinctive giving the tree a diseased appearance. The buds are surrounded by the leaf scar.

 

 

Salix spp.

Willow

 

Willow (Salix spp.) is easy to identify in the winter. It has slender twigs and one bud scale.

 

 

 

Tilia americana

Basswood

 

Basswood (Tilia americana) has reddish (or greenish) asymmetrical buds that are offset from the leaf scar. Each bud has two bud scales. Each bud scar has two small stipule scars.
Copyright 2013 by Donald Drife

Webpage Michigan Nature Guy
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