MOUNT DESERT — The Mount Desert Island Mushroom Club, a private Facebook group for local mushroom and plant foragers, took an outing to explore the trees and shrubs of MDI on Nov. 21.
Members of the group gathered at the MDI High School’s adult-ed parking lot to take a walk around the Kitteridge Brook Forest and learn about forest ecology.
Club administrator and College of the Atlantic graduate Willow Cullen Torrey led the group and explained how local trees and shrubs, even some without leaves, can be identified.
“It’s important to know about the organisms we share this land with, what their lives are about and what it is like to be a birch tree,” said Torrey.
The group followed Torrey to a red oak tree to learn what made it different from other species of trees. “What makes a red oak distinctive are little valleys in between their plates of bark so as they grow overtime, they expand outward and their plates of bark separate from each other that leaves little crevices,” Torrey said.
Between the valleys of the tree bark, a light, brick-red fungus can grow, which makes a red oak distinctive. Though the evergreen hemlock tree has similar bark characteristics, it does not contain similar leaves.
“The structures of these trees are also completely different. A hemlock tree is straight up whereas the branches of a red oak tree will spray out whichever way the light is,” said Torrey.
Similar to other oak trees, a red oak has acorns but its buds are completely different. Torrey ripped off a branch of a red oak that contained clusters of buds with shingles and overlapping scales for the group to examine. The shingles and scales are called leaf scars and can also be used to identify different species of trees.
Torrey led the club members down a path to examine a white pine tree. “The only way to find exactly how old a pine tree is would be to either cut it down or core it and count the number of rings inside,” she said.
A white pine conifer tree expands one ring per year, though Torrey said you can get an idea how old it is by how thick it looks. It takes up to 50 years for a conifer sapling to become a semi-adult tree capable of bearing fruit. Conifer trees, such as white pine species, benefit from surrounding trees and fungus to grow. According to Torrey, if white pine doesn’t get enough sunlight, it can get glucose and micronutrients from fallen logs.
“Many people have been taught to assume that trees are crops that they can cut down and plant more of. People think they will grow back, but when they cut down a mycorrhizal network of trees at once that provide nutrients, they have disrupted most of the ecosystem,” she said.
Farther down the trail, the club members found a speckled alder shrub. According to Torrey, the speckled alder took less time to evolve, whereas conifer trees have been around for millions of years. Like a birch tree, the speckled alder contains catkins that bear clusters of flowers. Pollen in the air and their fruit help fertilize the speckled alder. What makes a speckled alder different from other plants is that it does not rely on animals to pollinate it.
“A word that some of you might know is monoecious versus diecious. The words mean ‘single house’ or ‘two houses,’” Torrey said. “The speckled alder has the ability to protect its own pollen.”
Torrey also spoke about how the relationship between trees and humans has changed over time. “Trees are communities of individuals that have as much of a right to exist as we do, but as humans we often think of trees as lumber, paper or a thing to cut down, but they are a living creature,” Torrey said.
To join Mount Desert Island Mushroom Club, visit its Facebook page.