While cross-country skiing along a shoreline in early January, we noticed something unusual.
It was a mature, oak tree damaged on the base by what was apparently a beaver, given a smaller-diameter berry tree felled nearby in the snow.
This scene prompted the question: Would the beaver, likely from the lodge across the lake in the cattails, come back to munch on more of the hardwood oak tree this winter?
And also, could this oak, with the few brown leaves of autumn still hanging from the top until spring, continue to live and help protect the shoreline from erosion, provide shade for the beach and a nesting site for summer’s songbirds?
Farther ahead, along the shoreline, were more trees, including oaks, that also sustained damage.
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To help answer these questions, we checked with our local Minnesota Department of Natural Resources (DNR) Wildlife and Forestry personnel, and researched a variety of educational websites, including www.dnr.state.mn.us/livingwith_wildlife/beaver/index.html.
We learned that beavers can sit balanced on their webbed back feet and paddle-shaped tail to fell a tree.
In order to protect the remaining trees along the shoreline, the DNR site explains that 30-inch-tall, hardware cloth is helpful to loosely wrap individual trees.
It also explains the sustainable harvest of beaver by licensed trappers in-season, as well as Minnesota statutes that govern nuisance beaver activity.
The enamel of the beaver’s four front teeth, or incisors, contains iron, giving them the strength to gnaw through hard wood, such as the oak we observed. However, soft wood, such as willow, poplar and aspen are preferred.
The iron is also responsible for the orange tint of a beaver’s incisors.
The wood itself is not what provides the beaver’s nutrition. It is the living cambium cell layer of the tree trunk, just underneath the bark layer of the tree, that is part of the beaver’s diet. We were advised that an oak tree is hardy, so if much of the cambium layer is still intact, the tree may continue to live.
In late autumn and winter, beavers eat from their stores of wood, twigs and leaves buried underwater, as they stay warm in their protective lodges made from harvested wood, vegetation, mud and rocks. The activity of constant chewing of wood helps maintain and sharpen the beaver’s teeth, which continue to grow over their lifetime.
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In spring and summer, beavers eat leaves, buds, twigs, stems and roots of water plants. They do not like juniper.
If you hear a sharp slap on the water while sitting on the dock in the summer, you’ve likely been spotted by a local beaver swimming along the shoreline checking out potential food stores.
If beavers are present in your area, it’s best to protect the leafy shade trees you want to maintain along the shoreline, so they continue to provide wildlife habitat for migrating songbirds.
The DNR site above also provides a link to their informative “Lakescaping” web page for additional information on shoreland management.
Email hccolamn@gmail.com to arrange a complimentary shoreland advisor visit.
Members of the Hubbard County Coalition of Lake Associations write a monthly column in the Enterprise regarding water-related opportunities in the region.
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