Michigan boasts around 100 tree species, depending upon how a tree is defined. It's impossible to fully understand a forest without knowing what grows there. Trees are not the only life form, of course, but they are the dominant life form and impact everything that occurs in the forest. It's difficult to fully appreciate the amazing natural resources of Michigan without considering forests.

There are about a dozen characteristics available to help identify trees. Learning which subset of characteristics to use for a particular tree is where practice and skill are needed. Some characteristics are seasonal, such as leaves, fruits, and flowers. Most others are year-round, such as twig and branching patterns, buds, bud scars, bark, tree form, site, and tree associates.

For some trees, paper birch for instance, most people only need to look at the white, peeling bark. Easy. Although, sometimes pale versions of quaking aspen have been mistaken for paper birch. Trees with acorns are one of several oaks. Maple leaves have a distinct palmate shape.

Many people refer to all conifers as "pines," when most conifers are not pines, especially in the Upper Peninsula.

That's just not correct. Pines make up only about 42% of the conifer volume in Michigan and only 24% in the U.P. Northern white cedar is, by far, the most common conifer in Michigan.

Because there are only about a dozen common conifers (only four are pines!) in the forest, and identification is fairly easy to learn, beginning a tree identification quest with the conifers will build confidence.

Another good tactic for beginners is learning the 10 most common tree species first: sugar maple, red maple, white cedar, red pine, quaking aspen, northern red oak, white pine, bigtooth aspen, hemlock, and basswood. Once these trees are known, comparing them to unknown species will often make the identification process move quickly.

Using easy seasonal characteristics is another good way to learn to identify trees during the "off" season. Finding cherries goes a long way to segregating the cherry species. While doing that, it's a good time to observe other key features, such as bark patterns and buds.

Atree with an opposite branching pattern narrows the choices down to maples, ashes, and dogwoods. Once you know that, it's not too difficult to use a field guide to learn the species. Make sure you have a tree and you're not looking at a shrub. Some shrub species also have opposite branching.

Leaves are a popular way to learn tree species, and they're a good technique during the growing season. Some tree species have variable leaf characteristics, so be cautious. Use multiple samples from the same tree to get an "average" appearance. Again, once you know the species, take the time to notice other characteristics that will help you identify the tree during the leaf-off season.

During the winter, leaves can still sometimes be a good identification feature. Beech and ironwood often retain light brown leaves throughout the winter. Similarly, red oaks and sometimes sugar maples hold onto some of their leaves that are lower down on the tree. All of the conifers, except tamarack and larch, have needles year-around.

Considering where the tree grows can be quite helpful, especially for sites that are particularly dry or wet. A pine on a dry sandy plain will most likely be jack pine. A broad-leafed tree in a swamp will likely be black ash or one of the elms.

Black and white spruce can be difficult to distinguish by needle appearance, but if it's in a lowland site, it's probably black spruce. If the site is upland, it's probably white spruce.

The more trees you know, the easier it is to learn more. One of the best field guides is "Trees of Michigan" by Linda Kershaw. Norman Smith's "The Trees of Michigan and the Upper Great Lakes" is also good.

For the U.P. and nearby regions, the U.P. Tree ID Web site is good at http://uptreeid. com. Happy hunting.