Understanding the Twig
In the winter, the twigs of a tree can hold a lot of answers when identifying trees. Using the twigs is considered easy as they are arranged the same way the leaves are arranged - either opposite from each other or alternately.
Terminal buds - buds that are found on the tips of a stem or branch.
Lateral buds - buds that grow on the sides of a twig or branch.
Bud scales - small leaves that grow around outside of the bud. If there are no scales, the bud is considered "naked."
Bud scale scars - tiny dots that can be seen inside the leaf scar after the leaf falls.
Leaf scars - scars left on the twig after the leaf falls.
Lenticels - small, lighter colored spots on the back of the twig. They are tiny openings the allow air in & gas out.
Nodes - leaf bearing joints of the twig
Pith - the spongy center tissue of the twig.
Vascular bundle scars - where the xylem entered the leaf and phloem entered the twig.
Basic tree identification usually begins with the easiest question to answer, regardless of season or state of the tree’s life cycle. Is it deciduous or a conifer? Deciduous trees will lose their leaves in the fall and grow them back every spring. Conifers, also known as evergreens, maintain their leaves and colors all year round. In the winter, it is obvious which trees are evergreens and which ones are not.
Leaves are by far the easiest way to identify trees. When using the leaves to identify trees, you have to consider their arrangement on the stem, whether they are simple (a single leaf) or compound (several leaves attached to a midrib) and the overall shape of the leaf. Shape characteristics include: the edges (or margins) and if they are smooth, toothed or lobed; the length of stems, or petioles; the shape of the tips and bases of leaf; and the surface details - all important in distinguishing a leaf from one species to another.
Each category and species of tree has a unique shape and look to their leaves, making it a simple way to identify trees. But when deciduous trees lose their leaves as winter draws near, this way is no longer an option. When it comes to winter tree identification, knowing the placement of buds, the texture of the bark and the shape and size of the twigs are the best ways to identify the tree. Your other senses – smell, touch and even taste – may also come into play.
Identifying Deciduous Trees in the Winter
Tree identification always requires a little detective work. In the winter months, identifying trees takes a bit more scrutinizing. Since there are no leaves – on the deciduous trees, that is - it’s best to study the twigs, buds and bark. The following is what to look for:
• Twig markings, such as the bundle and leaf scars, offers information as to how leaves are arranged when present. They can also tell you where the buds grow. Virginia Tech has a great Twig Key that will take you step-by-step in determining what tree your twig came from.
• The shape, size, color and texture of the buds are never the same in species. Buds bloom into flowers and leaves. Flower buds form in various places and are often much larger than leaf buds. Leaves form as either terminal buds –found at the ends of twigs, or lateral buds - along the sides of twigs. Most buds have protective scales that enclose the leaf tissue. If no scales exist, the buds are considered naked. The number and arrangement of the buds on the twigs are also important.
• Look to the branches! All trees have either opposite or alternate branching. Alternate branching means that the twigs and buds grow off a main branch one at a time. Opposite branching is when twigs and buds grow off a main branch in pairs. Ashes, dogwoods and maples are examples of opposite branching. Examples of alternate branching would be birches, sycamores and tulip trees.
• Those who are more experienced when it comes to identifying trees may find the answers in the bark. While the bark of a tree changes as it matures and varies by geographical region or growing conditions, it can be an easy to determine the species of the tree. All specie’s bark has a difference in color, thickness, texture and pattern. Learning the feel of the bark with your hands will help you remember the bark more quickly than remembering its visual pattern. Feel for hardness and scaliness as well. Some species tend to peel its bark. For example, shagbark hickory peels vertically in large, thick, curving strips while the paper birch peels horizontally in large strips.
• Scratch & sniff! The smell of the inner bark can also help you decipher the tree’s identity. In fact, the identity of certain trees can be found just by scratching off a bit of the outer bark and giving it a whiff. For example, the yellow birch smells like wintergreen which is useful when determining what kind of birch you are identifying. Other trees that give a scent are Sassafras, which is spicy and can be quite strong, and wild cherry has a bitter almond scent.
Before setting out in the cold, make sure to bring along a good field guide to assist you in figuring out what is what. There are several guides out there to choose from, all appropriate for beginners to experienced foresters. Marion T. Jackson’s 101 Trees of Indiana is a great guide as is Trees of Indiana Field Guide by Stan Tekiela.
Conifer Tree Identification
Conifer trees are easy to spot in the winter months. Yet the similar green needles or scale-like leaves found on the various species can be tricky to identify. One way is to feel its foliage; are the needles thin and soft or are they thick and sharp. Noticing how they are bundled is a good clue as well. Cones are another indication. If present, the shape and size will help distinguish from one species to another.
Conifer trees in Indiana include bald cypress, cedar, Douglas-fir, fir, hemlock, juniper, larch, pine and spruce.