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Dendrology: The Science of.....

Ancient Greek: Dendron, (Trees), Logia, (Study). The study of trees before leaf out is a fascinating world. Each species of tree is unique at this time of year giving away clues to its identification. Last Saturday we had a wonderful group of people attend our Dendrology workshop led by Master Naturalist, Bob Bowles.

Participants of April 6, 2024 Dendrology workshop

Bob shared with us some useful ways to identify trees before they leaf out and flower:

  • tree location - uplands vs. lowlands (wetlands) vs. transitional areas (Coefficients of Wetness)

  • bud arrangement on the branch - alternate vs. opposite

  • deciduous vs. coniferous trees

  • deciduous trees that keep some of their leaves during winter

  • Terminal Bud - the bud at the end of a twig

  • Lateral Bud - buds along the sides of the twigs

  • Bud Scales - protects the developing leaf

  • Leaf Scar - attachment of a leaf to the twig from a past season

We learned that White ash, American elm, Sugar maple, Oak, White spruce, White and Red pine are upland trees. Lowland trees consist of Black ash, Willow, Eastern white cedar, Silver maple, Freeman's maple, Poplar, Black spruce and Speckled alder. Trees located in transitional areas are Green and Red ash, Cherry, Yellow and White birch, Tamarack and Eastern Hemlock.

Black cherry buds

Red Maple Buds

Photo Credits: Michael Elmer

Bob talked about the bud arrangement, whether the buds were opposite each other or alternate. We observed an upland, White ash tree and found the twigs and branches are opposite to each other. Bob gave us the mnemonic MAD.

M for maples, A for ash and D for Dogwood. Whenever you see a tree with opposite branches you know it is one of these species.

Next, we discussed deciduous and coniferous trees. Deciduous trees shed their leaves during the fall season, like poplar, birch, ash and maple just to name a few. Coniferous trees keep most of their needles during the winter months, such as spruce, pine, balsam fir and cedar. Trees that keep some of their leaves during the winter months are beech, oak and hornbeam.

Bob also used a Tree Identification Key. The key is used to make it easier and quicker to identify the tree or shrub. It takes a little time to become familiar with using the key, but once you know what you are doing the key becomes an invaluable tool.

Bob moved on to talk about bud scales. They play a significant role in the life and health of the tree. Here is what he said;

Trees, shrubs and vines form their flowers and leaves for the following growing season in early fall and pack them tightly inside of winter buds. They cover these winter buds to scale to protect the leaves and flowers inside for the harsh winter temperatures, snow and ice. On warm spring days when the time is just right, they open these winter buds and unfurl the leaves and flowers inside for the new growing season in early spring. 

We also observed mosses, lichens, liverwort and a Garter snake (Thamnophis) during our journey through the wetlands. Bob pointed out several species including Tree apron moss (Anomodon attenuatus) and New York Scalewort (Frullania eboracensis). 

Thank you Martha for scribing and for taking notes. Martha's organizational skills, taking notes and recording data are second to none.

Overall it was a great learning day with sunny skies and temperatures around 12C. We will keep you posted about our upcoming Alvar Tour walks and Moss workshops and much, much more. Til then...

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