A group of us spent a misty morning at Borden’s Pond Conservation Area a few Saturdays ago looking at trees. You might think this is the worst time of year for doing such a thing—the woods leafless and frozen and the greyish tree trunks quite indistinguishable from one another. But really, it’s a great time for practicing and delving more deeply into the botany of our woody, twiggy plants (trees, shrubs, bushes, etc.), the study of which is officially called “dendrology.” In fact, what is so unique about botanizing with trees is that—unlike most herbaceous or non-woody plants that need to be flowering to fully key them out—it can actually be done in winter, without flowers, and done quite simply, once you know what to look for. Without the leaves present, you really get to test your identification skills focusing on the dormant elements – the 3 Bs of a tree: branches, buds, and bark.
The first thing to look for when identifying a tree is its branching pattern. This applies to branches coming off the trunk, twigs off the branch, and leaves off the twig—all of these will be organized the same way.
There are three types of branching patterns: opposite, alternate, and whorled. Most trees have alternating branch patterns, with branches, twigs, and leaves (or in the case of winter, buds containing next year’s leaves) growing in a staggered fashion along the tree
There are a small number of trees that have opposite branching patterns, where the branches grow from the same point exactly opposite from one another. There’s a fun little mnemonic device for remembering which of the trees in our region have opposite branches:
MAD CAP HORSE which stands for…
- • M – Maples
• A – Ashes (and anything in the Olive family, Oleaceae
• D – Dogwoods
• CAP – Anything in the Caprifoliaceae family: elderberries, honeysuckle, all viburnums, nanny berry
• HORSE – Horse chestnuts, anything in the horse chestnut family (Hippocastanaceae – different than the chestnut family), which in North America is primarily the buckeyes
- • M – Maples
Whorled is the least common branching style where branches/twigs/leaves radiate from a single point circling around the stem. This often gives the plant a twirling kind of look to it. (See image 2 of slides)
Once you’ve determined the branch arrangement, then it’s important to look at the buds. Buds contain all of next year’s growth and are the place from which the leaves and flowers emerge in springtime. The bud of a tree is very distinct, often even more so than the leaf. Some trees’ buds are long and thin and pointy, others are bulbous and round. Some are smooth, others shingled, others covered in a soft fuzz. Some are dark in color, others light or tipped with white. Whatever the case, honing in on the unique traits of a tree’s bud will help you confidently identify which tree is which.
Take a good look at the bud scar as well while examining buds up close.(See image 3 of slides) This is the marking left behind from last season’s leaf after it fell off in autumn. Typically, the bud scar resides just below (sometimes around!) the new bud on the twig, with a distinct outline to it. It is often lighter in colour than the rest of the bark with very small dark spots inside it where nutrients passed between the leaf and the wood during the summer. These little dots are called vascular bundles and they are shaped and organized differently on each tree’s unique bud scar.
Bark is another great tool for identifying trees, albeit quite tricky. The color, texture, and even the smell of the bark can give you significant clues as to what tree you are looking at. The bark sometimes looks different depending on the age of the tree, however, so it takes some time to familiarize yourself with it in all of its stages. Very young trees are often quite smooth until the growing and broadening of the trunk starts to split and fissure it.
There are a few trees that can be identified by the “scratch and sniff” method, meaning that if you take a thin twig and scratch off its outer bark, it will give off a particular scent! Black cherries, for instance, when scratched, smell just like bitter almond extract. Black birch is bright and vibrantly wintergreen-scented—it was traditionally a key ingredient in making root beer. Spicebush has a sweet cinnamon smell to it, along with its close relative sassafras, which makes sense because they are also closely related to trees such as bay and cinnamon itself (which by the way, is a tree bark)!
This leads us to some other useful clues, once you’ve gotten through your 3 Bs. Lingering fruit that continues to hang on to branches can be a great sign for helping identify a tree or shrub. Sumacs, wild roses, and winterberry holly (image 5 of slides) are all shrubs that cling to their bright red berries late into the winter. Look also around the base of the tree for nuts or what’s left of them, and if there’s no snow on the ground, the soggy brown ghosts of last year’s leaves for helpful hints, but bear in mind that leaves blow every which way in fall and some of the leaves under your tree might not match.