Among the trees

There are many plant forms living among the trees. Learning about these denizens can add greatly to forest appreciation.

Identifying tree species is a skill valued by many and to which many more aspire. For most foresters, this is an everyday practice. Less common, except among foresters and botanists, is the ability to identify the species of non-tree forest plant species. More importantly, perhaps, is the knowledge of why certain species grow in particular places and what that might mean from an ecological perspective.

This, of course, is where most of the fun lies. This is learning to read the landscape. It’s a life-long endeavor filled with richness.

Mature trees dominate the ecology of a forest, mostly through casting shade and soil development. Soil types and water regimes also have a powerful influence. Think about what plants need to grow: light, nutrients and water. Plants also need carbon dioxide and oxygen too, but these are not limiting.

Usually, the first step in learning to read a landscape is identifying the plant species that live in a particular place. Michigan has about 1800 native plants and another 800 or so exotic species.

Trees have been mentioned. Once you learn to recognize a couple dozen species in the northwoods, you will be able to recognize most of the trees you will come across, even though there are dozens of other possibilities. But what other plants are out there in the forest?

Groups of non-tree plants include shrubs, ferns, mosses and moss-like plants, grasses and sedges, wildflowers, lichens and fungi. OK, fungi are not plants, but they are really interesting for several reasons. All of these species are important and tell stories, as you learn to read them. Each of these plant groups has its own identification book or set of resources. Some are easier to use than others. However, according to Michigan State University Extension it is always better to go out into the woods with someone who already knows the inhabitants. It is also more fun that way.

There are 40-50 common shrubs, including some troublesome exotics such as honeysuckle, buckthorn and autumn olive. Unless forms grow to be tree-like, identification resources can be difficult to find. Linda Kershaw’s book, Trees of Michigan, provides a good start. Viburnums, hazel, dogwoods and winterberry are a few examples of attractive shrubs that also provide food for many species of wildlife.

Ferns are common in many habitats, including some large and easy to learn species, such as bracken, lady, maidenhair, ostrich, cinnamon, and interrupted fern. Others are smaller and sometimes difficult to identify beyond the genus. The presence of certain fern species can reveal a lot about the quality and characteristics of forest sites. There are about 40-50 species that may grow in the Great Lakes region.

Mosses, liverworts, and club mosses are often difficult to identify. Species occur in both wetland forests and upland forests. Sphagnum is one of the more common species and lives in certain wetlands. The club mosses are particularly interesting. Princess pine and wolf’s paw are sometimes mistaken for tree seedlings.

Grasses and sedges are similar-looking, but their flowers and fruits are distinct from each other. Many species occur in woodlands, often on the edges and in openings. One of the more common species is Pennsylvania sedge, which can prevent tree regeneration in some forest stands.

Wildflowers are abundant in northern forests, especially in the spring before the tree leaves fully unfold. These species are among the more popular and visually-appealing among all plants. Their presence and abundance (or absence) can also be quite revealing about ecological characteristics of a particular site or location. A couple of dozen wildflower species help form the basis for “habitat typing”, which is a way to assess a certain site for which tree species will grow best. There are a surprising number of non-native species.

Lichens are a particularly fascinating combination of fungi and algae that live in a cooperative, or symbiotic, relationship with each other. The fungus provides moist habitat and protection for the algae. The algae photosynthesize and help provide food for the fungus. Lichens take on three general physical forms: crustose (crusty), foliose (flattened leaf-life) and fruticose (more branch-like). Lichens grow on almost any base such as a rock, tree bark, old barn, etc. “Old man’s beard” is a showy lichen that grows in trees where humidity levels are high. Lichens are sometimes mistaken as harmful to trees.

Lastly, but far from least, are the huge number of fungi which take-on such forms as slime molds, sacs, toadstools, brackets, jellies, puffballs and many others. Fungi provide critical services in all ecological situations. They are also highly variable, colorful, and photogenic. Many are edible. Some are poisonous. Mycorrhizae form relationships with tree species that allow trees, and the mycorrhizae, to better survive. Some tree species may not grow well without their companion mycorrhizae. George Barron provides a good book about fungi and identification in Mushrooms of Northeast North America.

Walking through the forest offers far greater appreciation and satisfaction when more of the living things can be identified and their functions known. A forest is much more than mere visual quality. It’s sort of like going to a party where you’ve known everyone for a long time, as opposed to knowing nobody. The people are still people, but when you’re familiar with a bunch it’s usually a whole lot more fun.

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