Environmental Almanac

Learning to See Trees Through “New Eyes” at Allerton

Participants at the Allerton Winter Tree Identification Hike looking up at a state champion 
swamp white oak

Hike participants look up at a state champion swamp white oak Rob Kanter

If you were scheduled to lead a lightly advertised tree identification hike on a frigid Saturday morning in January, you might anticipate working with a small group. That was not the case last month for Nate Beccue, Natural Areas Manager at the U of I’s Robert Allerton Park near Monticello. “I printed 20 copies of my handouts” he said, “and I thought I’d have extra.” As it turned out, some participants would have had to share even if he’d printed 100.

Most people who can tell the difference between a maple and an oak in summer have difficulty in winter because they’re naked—the trees, that is, not the people. Beccue’s goal was to equip us to use other cues to tell them apart. He said it was okay to look around on the ground for leaves to confirm other evidence; that is, the presence of white oak leaves can tell you there’s a white oak nearby. But in a forest where fallen leaves are mixed together, you can’t use them to tell which tree is which.

At our first stop, Beccue spent some time explaining how the pattern of buds on twigs helps to begin sorting trees into groups. In Illinois, trees that put out leaves in pairs on opposite sides of the twig are either maple, ash, dogwood or horse chestnut. That’s a group he suggested we could remember by thinking MAD Horse when seeing opposite leaf buds on a twig

All of the rest, including oaks, hickories, walnuts, and others, have leaves that grow from the twig in an alternate pattern.

Beccue also explained some of the ways the bark of trees can be used in winter identification. He cautioned, however, that the analogies commonly used to describe bark do not work equally well for everyone. That was evident in our group when he compared the irregular pattern of ridges and fissures in the bark of northern red oak with ski trails. Ski trails? That clearly didn’t conjure up anything familiar for some of us flatlanders.

The group had an easier time with Beccue’s point of reference for the dark, flaky bark of a wild cherry tree, which he compared to burnt potato chips. I think everybody got that one.

Bitternut hickory bud

Photo Credit: Nate Beccue

To tell the difference between trees that are closely related, Beccue called our attention to some pretty subtle differences in terminal buds, which are the ones that grow at the ends of branches. I need to review those for myself and won’t try to explain them here. But I will tell you about the one I remember for sure. That’s bitternut hickory. If you’re looking at a bright yellow terminal bud—the color of mustard, or sulfur—the tree in question is a bitternut hickory.

Our winter tree hike at Allerton ended at the most spectacular specimen of the day, a towering swamp white oak in the bottomland forest along the Sangamon River. It’s the biggest one of its kind in the state, and will soon be added to the Big Tree Register maintained by UI Extension.

As we made our way back to the visitors center, a friend I met up with on the hike mentioned that he had just recently begun identifying the trees he comes across near home in Urbana. “It’s like seeing the world through new eyes,” he said.

I think that’s also the gift of a walk with a naturalist, new eyes. Such eyes enable a person to appreciate not only a swamp white oak in a bottomland forest, but also one that grows as a street tree.

Further opportunities for getting to know the natural areas of Allerton--and developing new eyes for the everyday world--are in the works for the months to come. The first, which is described as a “semi-rugged, three-mile, off-trail hike,” will take place on the morning of Saturday, February 21st. Details about that and future events can be found on the Allerton website at http://tinyurl.com/AllertonHike.

Or keep up with Allerton on facebook via “Allerton Park and Retreat Center.”

Tree ID Resources from UI Extension (and beyond)
Forest Trees of Illinois ($12)

Tree Identification Chart ($3.50)

A Key to Missouri Trees in Winter ($3)