February
by Master Naturalist Pam Johnson.
I have been watching reruns of old Sherlock Holmes series. Arthur Conan Doyle was the first mystery writer that I ever read. I have always loved a mystery. I loved Holmes explaining to Dr. Watson how he recognized many facts about a person just by observing details about that person before they even tell their stories to him.
I think that looking at trees in winter is like being a Tree Detective. We have to observe closely the bark patterns and the leaf scars in the absence of leaves. We can then investigate the possible trees that in general match the observations. This can be done with references: iNaturalist, books, and online searches. We can then compare our observation to those we find in our research and draw a conclusion.
One thing to observe in winter is tree bark. It is an especially useful tool for tree ID. There are various ways to describe what a bark might look like.
Watch the following video! It offers great visual clues you can look for. Identify 11 Trees By the Bark (Easy Tips)
Here are a few descriptions that I use to help me remember when looking at bark.
Shaggy, like Shagbark Hickory
Ropey, like Black Walnut
Warty, like Hackberry
Peeling, like River Birch
Flat white ski runs, like Red Oak
Deep furrows, like Bur Oak
Potato chips, like Black Cherry
Some species of trees are more difficult to identify only from the bark. Another clue to help you identify is the anatomy of the twig. Each species of tree has its own unique characteristics. One of those characteristics is the leaf scars which are much like fingerprints. They can often tell you what species you are looking at. The twig leaf scars are something you can take a picture of and submit to iNaturalist for identification.
In winter when submitting trees and shrubs for identification to iNaturalist, I take pictures of 1. the leaves, if present, on the ground, 2. the leaf scars, 3. the bark of the tree, 4. seeds if present.
I notice if the leaf scars are alternating on the stem or opposite each other. This arrangement alone can put the tree into one of the following genus: for opposite I remember the genus based on the abbreviation MADHorse: Maple, Ash, Dogwood and Horsechestnut.
Take a look at drawings of some of these finger prints on the following chart: LEAFWinterTreeIDKey.pdf
Observing what is going on during a season becomes second nature to the nature sleuth. If you have lived in the Midwest in the winter for long, you have witnessed an ice storm or a heavy snow. I love the quiet of the day after except for the sounds of snow falling from roofs and trees.
In Bernd Heinrich’s “When the Bough Bends” ( Natural History, 1996) he gives some theories on how our trees weather these storms. He, like Sherlock, has surmised the differences in species by observation. According to Henrich the birch seem to gather the most ice. He tested his theory and proved that it did collect more ice. Ash trees collect the least ice. Sugar maples, red maples and apple twigs were in the middle.
He surmised that the architecture of the tree is important to its ability to direct water off the twigs. The more the twigs point upward (as in the ash and maples), the less water would freeze on the twigs. The water would be directed inward towards the trunk where it would do less harm. The birch on the other hand directed the water outward on the bending branch therefore making it prone to breaking.
A more important function of the trees’ structure is to place leaves to capture sunlight. Deciduous trees evolved special enzymes that act to abscise the leaves from the tree as days shorten. In Northern climates, this also provides a defense against snow and ice.
Most conifers retain their leaves (needles) in winter. I see the limbs of conifers bending under their load of snow but they seldom break. They are collecting the flow of water outward, not inward as with candelabrum-shaped hardwoods. Because of the Christmas shape of the trees, the upper whorls of branches press down on the next layer which supports them. As they bend, snow slides off creating the sounds you hear in the still air. Each tree has developed its own method of surviving our winter weather storms.
My explorations on the JDCF preserves always pose a mystery to be solved. Like Sherlock, I always have questions to answer. Like Watson, I keep records of my walks in my journal. What insect do I find on the trees throughout the seasons? Which insects are harmful and which are not? Which trees attract the most birds and why? Why do the leaves turn color? When do the leaves fall and when do the leaves come out in spring? I hope that you will visit our preserves, ask your own questions and start solving the mysteries!
Turkey at a JDCF preserve
Winter prairie
Winter trail at Casper Bluff
