The benefits of dead trees

Limbs, trunks and branches devoid of life are just as important to the forest ecosystem as healthy trees

|  Story by Cindy Cain  |


The word “forest” conjures up images of healthy stands of trees, green with promise in the spring and sporting a rich palette of golds, reds and oranges in the fall.

But forests also feature dead and dying trees. And limbs, trunks and branches that are devoid of life are just as important to the forest ecosystem as healthy trees.

“Everything in the forest benefits from dead or dying trees,” said Bob Bryerton, an interpretive naturalist with the Forest Preserve District. “They are very important for the health of a forest. Dead standing trees, live trees that are compromised by fungus or insects, and fallen branches or trees that are on the ground all provide habitat and food for animals that live in the woods.”

Some species are particularly geared to benefit from dead trees.

“Woodpeckers rely on dead or compromised trees in order to nest and also as a source of food,” Bryerton said.

(Photo courtesy of Paul Dacko)

Dead trees are so important, many conservation and preservation agencies leave them in place when they fall.

“In places where management practices have removed dead or dying trees, the forest fails to thrive,” Bryerton explained. “Dead trees provide hiding places and habitats for numerous insect species (ants, beetles, bees and wasps), amphibians (salamanders, toads and frogs), mammals (raccoons, squirrels, bats, deer, coyote and fox), reptiles (snakes and turtles) and host fungi, lichens and other organisms that are all crucial to the overall health of the forest.”

Left: Raccoon (Photo courtesy of John Sullivan; Center: Fungus (Photo courtesy of Kevin Keyes); Right: Downy woodpecker (Photo by Glenn P. Knoblock)

For instance, a tree that is dying and has peeling bark can provide roosting spots for bats and other small animals, Bryerton said.

“And insect-infested trees provide food for a wide variety of birds,” he added.

Branches or trees that fall on the ground also have their role in the ecosystem.

“They provide hiding spots and places that hold moisture or give cover to animals,” Bryerton said. “And as they finally are broken down by fungus, bacteria and insects, they provide crucial minerals to the soil that helps new plants grow.

“So basically, you can’t have a forest without dead trees,” Bryerton concluded.

(Photo by Tina Arteaga)

Here are some more interesting facts about dead trees, also called snags, from the Northwestern Illinois Forestry Association:


•There are at least 38 species of birds that either excavate nest holes or use existing holes in dead or dying trees. In addition, 29 species of mammals also use tree cavities.


• Birds of prey frequently use snags as hunting perches.

• Many songbirds that occupy habitat on the forest edge use snags as singing perches.

• Woodpeckers use undecayed portions of snags as drumming sites to signal their territory.

• Primary cavity nesters, such as woodpeckers, typically excavate their own nest sites. Secondary cavity nesters, such as screech owls, use natural cavities and abandoned woodpecker excavations.

(Lead image by Chad Merda)


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