How to Identify Trees in Winter

by Preschool Teacher Susan Carton, who is studying to become a Master Naturalist

One of the best things about studying to be a Master Naturalist is that 

the more I learn, the more I see. 

I have always loved the trees in our neighborhood of Hyde Park. Now that I've learned a few things about their history, such as why certain trees flourish here, how they grow and survive, and their diversity, I am noticing even more about them. Quite fitting for the upcoming holiday of Tu B'Shvat (the New Year of the Trees in Israel), I recently participated in a winter tree ID workshop at the Sand Ridge Nature Center. Well, the take-away is that it’s pretty hard, but it is something that you can learn and study your whole life. Nature is like that!

Bark seemed the obvious place to start. 

My classmates and I learned about the distinctive bark of some trees: the almost tile-like black shingles of the cherry tree, the peeling bark of sycamores, the bumpy bark of hackberries, and the smooth reddish bark of dogwoods.

We also learned to observe the general shape and size of trees: Does the trunk split near the ground, or are there many small trunks? Do the branches form one long column like on a white oak, do they spread out in a circle like on a red oak, or do they curve and twist like a crabapple does?

Serviceberry Tree (like tree our school recently planted at Promontory
Point in memory of our school matriarch Millie Miller)

These days I’m seeing twigs and buds everywhere. Every tree in Chicago is full of buds right now. You can study the buds (are they clustered, single, scaled?), the leaf scars (are they round, crescent shaped?), and the twig placement (do the twigs grow opposite each other or alternate along two sides of the twig?).  

Twigs intrigued me the most. 

Twig illustration from the Field Museum's Guide to Winter Trees

Twig structure and formation is so specific to each tree species that you can pretty much identify it by just observing the twigs. One place to start with twigs is their placement on the trunk. Do the twigs grow directly opposite each other or do they alternate along the branch? There are relatively few trees with opposite twigs. Here’s a way to remember them:

M maple

A ash

D dogwood

Cap Caprifoliaceae or honeysuckle

Buck buckeye

Horse horse chestnut

Next time you are looking at a bare winter tree, see if it has “opposite” twigs. If it does, it will be one of these trees. It’s a place to start.

As you can imagine, you really need a field guide to identify most trees, but now you have an idea of what to look for. The good news is that the Field Museum has just created a field guide for winter tree identification, and it will be on their website very soon.