On Saturday, December 2, a group of Boston area teachers searched for trees whose bark resembled string cheese, camo pants, saggy socks, or peeling paint! They found seven son flower (Heptacodium miconioides 1549-80*B), Japanese stewartia (Stewartia pseudocamellia 8-43*A), purple European beech (Fagus sylvatica ‘Atropunicea‘ 452-51*A), and paperbark maple (Acer griseum 279-62*A), among many other examples of trees with interesting bark. Teachers also enjoyed touching the bright papery bark of the white barked Himalayan birch (Betula jacquemontii 74-94*A) and the thick, rough peeling bark of the shagbark hickory (Carya ovata #12907*G). Children, and adults it turns out, really begin to see trees anew when they compare tree bark to familiar, everyday materials and food. The fun is in the search, and then using specific vocabulary to describe what is touched and observed.
The walk began at the Centre Street gate and continued down Bussey Hill Road, through the Leventritt Shrub and Vine Garden, onto Linden Path, and down Meadow Road towards the Hunnewell Building. Along the way, teachers learned about the many uses of bark as well as some of its functions. For example, indigenous Americans boiled shagbark hickory bark to extract sugar and medicinal properties, while birch bark can be used as kindling to start fires because it contains flammable oils that will burn even if the bark is wet. In addition, the exfoliating or peeling nature of some bark removes lichen than can block lenticels, allowing for higher rates of transpiration and gas exchange. Thick bark protects the tree from temperature extremes and water loss, and cracked bark is less attractive to herbivores. Who knew? As one teacher put it, “I had no idea there are so many bark types! I’ve never looked closely before and am excited to share with my students.”
Once inside, teachers could choose to make close observations of tree twigs. Reference sheets helped them to learn about and identify the scars, notches, and bumps on twigs (leaf scars, terminal bud scale scars, and lateral buds). Each twig is different, but all twigs will reveal their secrets upon careful study.
The second option was to create a model using coffee stirrers, straws, paper, wooden dowels, and cardboard tubes to represent the outer and inner bark (phloem), cambium layer, the xylem transport system, and pith inside trunks. As Thea, a participant, put it: “The tree models we made are a great way to demonstrate concepts that kids need more than observation to learn. I think kids in my program would love building these.”
The Arboretum for Educators is a free, monthly offering to Boston area educators who want to learn more about using the outdoors for science education. Join us next month, January 6, 2018, to learn about tree architecture!