Boxelder

Today was the final class of my 6-week Maine Trees, Top to Bottom course. For the first five classes we focused on a particular topic: basic tree anatomy and conifers; winter twigs and buds; leaves and photosynthesis; flowers and fruit; and bark, trunk and roots. The students eagerly met my objectives for them: become more observant, understand the terminology, and learn how to identify Maine's forest trees. We had a lot of fun, and we all learned a few things - including myself. 

I had misidentified this tree a few weeks ago, thinking it was a silver maple with its opposite red buds swelling early in spring and the proximity to the Androscoggin River. Weekly visits on my way to class provided an opportunity to observe the emergence of the male flowers with long filaments and anthers, and then the female flower's developing samaras. It wasn't until last week that the early leaves emerged from the leaf buds revealing divided leaves and its true identity - boxelder. The boxelder (Acer negundo) is the only Maine maple that doesn't have the characteristic palmately lobed simple leaves.

This is a female red maple flower. I learned that some Maine forest trees are dioecious (two houses) with male flowers and female flowers found on separate trees. These include the maples, ashes, honeylocust, poplar and aspen, and willow. Other trees are monoecious (literal translation, one house) with separate male and female flowers on the same tree. These include fir, alder, birch, hornbeam, chestnut, hickory, cedar, beech, walnut, larch, hophornbeam, spruce, pine, sycamore, oak, eastern white cedar, and hemlock. It has made for an interesting spring tree survey, looking for the male and female flowers and trees.

One class was devoted to bark. Until recently, tree identification was taught to me in terms of leaves and winter twigs. However, bark is right there in front of us - the first part of the tree we ever see.