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Walking in Beauty

February 21, 2024

A look inside a tree

Some of the towering trees at Flora Husselman Trumbull Nature Area have hollow bases. Kneeling and peering underneath, I can look right through to the other side.

At Borton Wetland Nature Preserve, a crevice in a tree trunk reveals a completely hollow interior. I put my phone up to the crack and took a few pictures. The inner surface appears black, textured and waxy.

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A deep crevice in the wood of this tree at Borton Wetland Nature Preserve reveals a shiny black, hollow interior (right).

Hollows form in many species of trees, and are a prominent feature of natural forests and woodlands. They act as a resource or habitat for a number of vertebrate and invertebrate animals.

In the case of the Borton tree, all of the heartwood is gone and only the outer layer of bark and cambium remain. The cambium layer is the “living” part of the tree trunk, circulating nutrients and energy from the leaves and roots.

Dead, standing trees are called “snags.” They provide homes for wildlife – from foxes, raccoons and squirrels to owls, songbirds and bats. They attract insects, a basic food group for wildlife, including pileated woodpeckers, which pound rectangular openings up to a foot long in trees and snags, creating doorways for small animals. There are often several holes in one trunk.

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Pileated woodpeckers like this one photographed by Char Ekroth make large, rectangular holes. Often, a series of holes is created in search of insects.

Woodpecker excavations that bore deep into the sapwood and heartwood can be linked to insect infestations. Trees can also be wounded by ice storms, wind or human activity. Like human skin, trees produce scab-like material to cover exposed cambium.

In the woods, you see burls and cavities high in trees, some big and deep enough to shelter birds or squirrels. They are a testament to trees’ strength and resilience and show that scars add character.

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