Do you want to learn more about trees?

Maine Trees, Top to Bottom is for anyone interested in trees - beginners, back-yard naturalists, and more serious enthusiasts. The variety of student backgrounds leads to lively discussions and shared learning (I always learn something new) based on published literature, direct observations, and oral traditions. If you're interested in trees and want to know more about them, this class is for you!

The class has evolved over the years and will continue to develop in its format and its teaching tools. Building on the Forest Trees of Maine and Natural Landscapes of Maine, the six-week class is designed to equip students to identify the tree species that characterize Maine's forest communities. Learn to use dichotomous keys and understand botanical terms as you look at trees close up and from a distance.

Currently, Maine Trees, Top to Bottom is structured into six two-hour sessions. Each session introduces a couple of tree related topics and includes hands-on specimen identification (leaves, twigs, bark, fruit, flowers) as well as outdoor practice on trees surrounding the venue. As might be expected, topics range from roots-soil upward to trunk-nutrient transport to leaves-canopy. Though trees are the focus, we also bring in discussion of natural communities and the relationship between trees and the animals that live in those communities.

Interested? Watch for the spring calendar at Lewiston Auburn Senior College. You can also bring Maine Trees, Top to Bottom to a place near you as a six-week class or as a four-hour introductory session. For more information, contact treestoptobottom@gmail.com.

First thing first

The first thing to know about trees is, what is a tree? Sounds like a simple question but go ahead, if you haven't thought about this before - what makes a tree a tree? This is one of the very first questions asked at Maine Trees, Top to Bottom.

Trees live for many, many years - decades and sometimes centuries. From its seedling start to its sapling stage and then as a young tree, it keeps reaching for sunshine at its top, stretching its roots through the soil at its bottom, and adding growth rings to its trunk. Shrubs also live for many years, but the above-ground parts of herbaceous plants (grasses, ferns, wildflowers) die back at the end of each season.

A tree has a single stem, unlike shrubs which have multiple stems at their bases. There are a few considerations to make here. For example, in a post-harvest forest you might find several stump-sprout trees coming out of one base, like the photo to the right. This happens after the original tree is cut down and a few dormant buds emerge and send up new main stems (trunks). Another scenario is where Gray Birch (Betula populifolia) or poplar/aspen may propagate vegetatively, that is, underground so you get a small grove of the same species. In both cases, think about the tree species and whether you'd usually, or ever, see it growing as a single-trunk tree. It is not uncommon to see a single Gray Birch or a lone Trembling Aspen (Populus tremuloides). Shrubs ALWAYS have multiple stems no matter where or when you see them - think of staghorn sumac, lilacs, or highbush blueberry.

A tree has a woody stem, unlike fibrous herbaceous plants. A woody stem persists year after year, adding more growth to the tips of the branches and roots, and more growth to the girth of its trunk. An example of a fibrous non-woody plant is blackberry whose dried canes persist through the winter, but new growth comes up every spring.

Size is another consideration when distinguishing trees from other plants. Mature trees are generally taller than 15 feet and have a diameter of more than 3 inches. Of course, tree seedlings and saplings won't meet these criteria but they will have single woody stems, and it's likely there are mature representatives in the same area. So that's it - a tree has a single woody stem and at maturity is taller than 15 feet with a diameter greater than 3 inches.

Class materials

Several years ago I studied with the Maine Master Naturalist Program. One of the assignments was to press and laminate a number of specimens - tree leaves, wildflowers, and ferns. I could see their value as a durable teaching tool. Over time I've perfected my technique and experimented with materials. Initially, specimens were layered between clear vinyl and clear contact paper, but the latter wasn't as clear as I might have liked and the former wasn't as stiff as I wanted.



These days, I use transparency film which is super clear and fairly stiff over clear self-adhesive laminating sheets. They're more expensive than contact paper and vinyl, but they're durable and clear which, to me, is worth the investment. You might try hot-laminating but I wonder if the dry-pressed leaves might crack as they go through the machine - maybe not, you could try it. The cold-laminating process is only a bit tricky with one goal - no wrinkles or bubbles. Of course, the other component of a laminated specimen is the specimen itself. For my tree class, I want representative shapes but also a good size for the collection. Sometimes that means selecting smaller-than-average leaves, especially if I'm also trying to get them in their opposite or alternate arrangement. Here's the step-by-step method I've developed over the years and mostly follow these days.

1. Locate the tree species of interest. Sometimes this means planning a field trip (hurrah! field trip!). For example, Chestnut oak's range is southern Maine and Balsam Poplar communities are mapped in the northern half of the State. 
2. Size matters to me. If possible, I collect samples that fit onto a 4" by 5.5" piece of film. This size fits into 4" x 6" photo pages which then go into a 3-ring binder. No worries if the leaves are bigger than that, I just put the laminates into a full-size sheet protector.
3. From the size parameter, I select a dozen healthy leaves of representative shape. Every tree has some that have an odd lobe or insect damage, and some species like red oak have sun-leaves and shade-leaves. If I'm collecting from afar, I might gather a few extras just in case I mess up (gasp!) with the laminating or maybe a leaf gets folded in the pressing book (it happens even when you're super careful).
4. Press these leaves into a field guide or handy book. If they easily fit into a field guide there's a good chance they'll meet my ideal size - and many field guides have a ruler inside the cover so that's helpful. Let the leaves dry for a week or so. If they're particularly moist at collection, I might check on them after a couple of days and transfer them to a dry book as needed. Damp leaves may darken or mold, and that's no good. You can also use a plant press though I find they're a bit bulky for the field. I have a plant press at home, but it's an extra step in a hectic schedule. That said, a plant press produces a really flat leaf.
5. You're ready to laminate! Cut the transparency film based on the size of your specimen. I usually go ahead and cut a dozen pieces so I'm ready for mass-lamination. Set them aside, out of your laminating area so they don't inadvertently get stuck up where they shouldn't.
6. Because they're super clear, lay out the laminating sheet where you've got enough light to see the edges. Begin in one corner and place your specimen, leaving a margin for the transparency film to stick. Carefully lay the cut piece of film over the specimen (bend the film just a little so you can lay the middle first, then ease the sides down to minimize bubbles or wrinkles) to capture the margin you left around the leaf. With your fingers, press from the center out, then press around your leaf - you want a good seal. Repeat this until the laminating sheet is full. You can get four 4" x 5.5" specimens onto one laminating sheet or two that are 5.5" x 8.5". 
7. If you want, add a label with a Sharpie. I use a numerical code so that I know what I've got but students have to focus on what they see. A wise naturalist once told me that once a student names something, they are likely to move on. I want my students to really look at these specimens, describe what they see, and to compare it to another specimen. Then give it a name.

So what do we have laid out here, "T005"? Do you see the bulge at the base of the leaf stem which isn't present at the base of the leaflets? This makes it a compound leaf - the entire thing is the leaf. The bulging at the base of the stem is where the bud develops. At the end of the summer, the leaf (that whole thing with three leaflets) will fall off and leave the bud exposed on the twig. In the spring, the bud will open up and produce a new leaf. The other interesting feature about these leaflets, if you look closely you can see it, is a little protuberance on one side of some leaflets. Almost like the hint of a thumb on waving hands. This tree is often planted in neighborhoods because it grows fast. A friendly tree - neighborhoods, waving hands - what is it? Boxelder, Acer negundo! In the same genus as maples. The "waving hands in the neighborhood" story helps me remember the tree.

Class materials: blessings from the Universe

This morning I poked around the White Pine (Pinus strobus) stand behind our house in search of new pine cones from which I might harvest some seeds. Unlike flowering plants whose seeds are enclosed within an ovary, conifers (gymnosperm = naked seed) bear bare seeds on the scales of female cones. I'd read that White Pine drops fresh cones from late August through September. Even though the seeds usually disperse before the cone drops, I imagined at least a few intact cones might make it to the forest floor. No such luck in the woods today.  

So I decided instead to go for a nice walk down the road just for some exercise and fresh air under a sunny, blue sky. As soon as I turned out of our dirt alley onto the paved road, what should appear? There on the asphalt, I saw this freshly dropped pine cone still bright green, coated and dripping with pitch. (insert imaginary audio clip: squeal of delight) What a find! Too sticky to pull apart right now, I collected it in a baggie (because I almost always carry a baggie or two for impromptu finds) and brought it home to dry out a bit.

With any luck at all, I'll be able to harvest some seeds which I plan to laminate along with the 5-needle fascicles. Blessings like this seem to happen just often enough for me to truly appreciate how the Universe provides exactly what I'm looking for.

UPDATE: It's been a week or so since I set the fresh pine cone on a south-facing window sill, protected by a sheet of waxed paper to keep the sap from getting onto the wood finish. After a few days, I bent and twisted the cone stalk to see if the seeds might be ready to release but only a few broken seed wings popped out. This morning (September 5th) I saw a couple of winged seeds had dropped from the cone - a gentle shake yielded many more! Notice how the now-dry scales have opened up. Now, the final step is to laminate the seed along with the 5-needled bundle.

Trees every day

It's two seasons and many months before the next Maine Trees, Top to Bottom class but that doesn't keep me from preparing. Collecting and pressing leaves occupies me from spring to fall. The goal is to include all the trees of Maine's forest in the teaching collection. Though not yet half full, the binders are getting thicker with each new laminated leaf specimen. Cones, samaras, acorns, and other 3-dimensional (non-pressable) items get dried out and stored in small divided containers. Bark and sections of tree trunks go into a larger plastic tub.

















Studying Maine trees isn't my only pastime, but it is one that helps slow down a sometimes crazy schedule. It gets me outdoors when I might otherwise get distracted with housework or errands. It satisfies my desire to find creative ways to share how important trees are to natural communities. At home, we find it's a messy hobby with the twigs, leaves and needles, and Tupperware filled with acorns all around the house. But it's joyous to see pine cones atop the open beams in our living room, to duck under dried chestnut leaves beside the desk, and to see wood carvings that my dad has given me. Trees and tree things inside and out - every day.