Want to improve your winter tree identification skills?  Here’s a good tip:  Look for marcescent leaves.

Marcescence describes leaves that have turned brown and are still attached to trees.  These withered leaves often persist on the trees until spring.

As you might expect, marcescence isn’t a feature displayed by too many woody plants.  When you see a marcescent tree or shrub, you can narrow down your ID choices to a relatively small number of species.  

In the temperate woodlands of eastern North America, marcescence is often displayed by hornbeam (Carpinus), beech (Fagus), witch-hazel (Hamamelis), hophornbeam (Ostrya), and oak (Quercus).  

No one is exactly sure why marcescence exists.  Here are a few hypotheses:

• It allows plants to photosynthesize longer into the autumn season.
• It deters herbivores from browsing twigs and buds.
• Marcescent trees provide shelter to animals that in turn provide nutrients to trees.
• Marcescent leaves, when they finally fall off, provide pulses of nutrients to their host trees.
• Marcescent leaves, when they finally fall off, smother new growth of competing woody plants in the spring.

All of these statements can be true to some degree, but it is uncertain whether any one of them is the true reason for marcescence.  

Still, you and I can use marcescence to our advantage when attempting to identify woody plants.  A good first step is to learn which woody plants are marcescent in our region.  We can then seek out these plants, spend some time with them, and fall in love with the process.

To learn even more tips for identifying trees, consider enrolling in Trees In All Seasons.  Today is the final day of the winter sale.

You can learn more and register here.

Also, if you’re interested in learning how to forage mushrooms this winter, consider enrolling in Foraging Wild Mushrooms.  This 4-season online course is on sale until the end of today, December 23.

Thanks for supporting nature education!

— Adam Haritan