Winter Medicinal Tree & Shrub ID

I have loved trees since I was a small girl, sitting high among their branches, making “soup” out of their spring catkins, and weaving small, supple crowns from their young branches. As a grown herbalist, for many years I focused on herbaceous plant identification. But one winter several years ago, I was missing the green, as I always do. Walking through the winter forests that year, I slowly became obsessed with winter tree identification. There is so much to see about trees and shrubs, I found, and in such a different way, when looking at them in the late fall, winter, and early spring.

Due to their bark and twigs, which are durable through all seasons, trees and shrubs lend themselves particularly well to wintertime identification. The value of winter tree ID is twofold for me. Firstly, I dearly miss the plants in the winter, and getting out into the woods helps me feel connected to nature during the long, cold Montana winters. Secondly, as an herbalist, I love to note which trees are growing where so that I might return to use them as medicines in the spring or summer months. Learn more about harvesting and using trees as medicine in my article Tree Medicine.

I always recommend revisiting the trees in the other seasons as well, to look for more identifiers and to get to know them better.

The following are the best tools for identifying trees and shrubs in the late fall, winter, and early spring months.

Look up the range of the tree to determine if the species grows in the area. where is it located geographically? Make sure the conditions are suitable for each species’ growth and reproduction. You can often find this information on a government website. The one for the United States is the United States Department of Agriculture Plants Database.

Next look at the habitat. Would the tree or shrub grow near a stream? For instance, willows, cottonwoods, and hawthorns are water-loving and tend to grow near rivers, streams, and seeps. Does it like moist sites, shade, or sun? Does it prefer to grow in an understory, in the woods, or on a north or south-facing slope? What companion plants typically grow in the same habitat?

Looking closely at the surroundings under and around the tree can also yield helpful clues such as last year’s leaves, stems, fruits, berries, seeds, and nuts. 

Leaves or none?

No matter the species of tree or shrub, every leaf has a finite life span; each will fade and fall at some regular interval. In seasonally changing environments, deciduous trees will drop their leaves in the winter. Most coniferous trees, such as pine, spruce, hemlock, and fir will retain their leaves (needles) for years. Interestingly, beech and oak leaves die, but many remain on the tree through the winter months. This retention of dead plant matter is called marcescence.

Bark

The bark on younger trees tends to look similar, making identifying young trees based on bark more of a challenge. Although subtle to extreme variation can occur, older trees usually develop more characteristic bark features.  Look for bark colors and textures. Is the bark spongy? Is it flaky? Is it smooth? Scaly? Fissures can develop when the outer bark splits as the tree grows. Fissures often occur in younger trees and develop into furrows as the tree matures. These furrows can make distinct patterns, such as the long, deep furrows with thick ridges of the cottonwood tree or the diamond-shaped ridges of the black walnut. Many birch trees tend toward flaky, peeling bark. Aspen trees have smooth upper bark with a light cream-ish color. Older aspen can have much darker and furrowed bark, dark brown to black in color, near the bottom of the tree.

Lenticels

Lenticels are the pores of outer plant tissue that provide a direct exchange of gases between internal plant tissues and the atmosphere. Bark is normally impermeable and the exchange or release of internal gases would be impossible without lenticels. In other words, trees breathe through their lenticels. They can be quite characteristic in shape, color, and texture. Some lenticels turn into horizontal lines as the tree gets older.

Buds

Buds contain next year’s stems, leaves, and flowers. Trees and shrubs produce buds in the summer to prepare for next year’s spring growth. This gives them an early start when spring temperatures start to rise. Bud scales are modified small leaves that tightly enclose the more delicate parts of the bud. They protect inner leaves and flowers during the harsh winter months. Terminal buds allow the stem to grow longer. They are the last buds at the tip of the stem. Warning: sometimes terminal buds can be broken off, so check several branches to make sure you know the true pattern of the tree. The number, color, and texture of the bud scales, size, and shape of the buds, and presence or absence of terminal buds are unique to each tree.

Leaf scars

Leaf scars are left when a leaf falls off a twig. Look at the shape, size, and location for identification purposes. Vascular bundle scars are small marks on leaf scars that indicate where veins from the leaf were connected to the stems. Look for the number and the position of the scars. 

Branches

Check to see if the branching pattern is opposite (across from each other) or alternate (staggering). Beware of fallen branches! 

You can use a helpful mnemonic for trees with opposite branches: “MAD Horse Bucks”. This stands for the following tree families: Maple, Ash, Dogwood, Horsechestnut, and Buckeye.

To look at branch color, focus on the youngest twigs with the newest growth.

Smell

I love to use many senses when identifying plants. Many trees have distinctive smells. If you can't tell just by smelling the bark, scraping a small bit of bark can often yield good results. Although some people will have different experiences and opinions, the following descriptions can help decipher some trees.

• Some birches, including Black birch (Betula lenta) and Yellow birch (Betula alleghaniensis), smell like wintergreen.

• Ponderosa pine (Pinus ponderosa) smells like butterscotch or vanilla.

• Wild cherry (Prunus serotina) and Chokecherry (Prunus virginiana) smell like bitter almonds.

• Cottonwood (Populus spp.) has a balsamic smell, reminiscent of sweet honey or musk.

• Sassafras (Sassafras albidum) smells deliciously sweet, like root beer.

• Eucalyptus (Eucalyptus spp.) smells clean, sharp, and slightly medicinal.

• Walnut (Juglans spp.) has a spicy citrus smell. Humorously, it was once described as “injurious to sensitive people” in an old herbal.

• Cedar (Cedrus spp.) has a spicy, earthy, woody aroma.

Commonly, we think about identifying plants mainly by their leaves and flowers. This is great in the summertime, but I love the idea of being able to identify trees in all phases of their life cycle, including fall, winter, and early spring. I hope you found this article a useful and inspiring place to begin getting to know medicinal trees a bit better.

Want to learn more about Tree medicine? Read my article here.

Here is an excellent beginning winter tree ID guide from the University of Wisconsin Stevens Point:

https://www.uwsp.edu/cnr-ap/leaf/Documents/LEAFWinterTreeIDKey.pdf

References:

https://www.litzsinger.org/wp-content/uploads/WinterTreeIdentification.pdf

http://www.ccfpd.org/Portals/0/Assets/PDF/WinterTreeIDpocketguide.pdf

https://www.thoughtco.com/beginning-guide-to-winter-tree-identification-1343460

https://www.extension.iastate.edu/forestry/tri_state/tristate_2015/Talks/PDFs/hayektree%20ID.pdf

https://www.thoughtco.com/beginning-guide-to-winter-tree-identification-1343460

© Elaine Sheff, Clinical Herbalist, RH (AHG)