To the undiscerning eye, fallen limbs and trees are a cluttered eyesore, warranting immediate removal or camouflage in order to avoid disrupting the appearance of a landscape.
Dead and/or fallen trees look very different to wildlife, however. In fact, a fallen log is prime real estate for a wide variety of wildlife, especially in the fall and winter when temperatures begin to drop to dangerous levels.
Trees play a critical role in creating habitat for wildlife even after they die. Standing dead trees are typically referred to as snags, and once they drop a log is born.
Both are important to keep around whenever possible. Unsurprisingly, forest wildlife evolved over millions of years when dead trees were not removed from ecosystems as they fell, and most of them rely on these dead trees for shelter, food, or nesting sites.
What tends to be regarded as an eyesore, or a reflection of lazy landscaping, is actually highly important for the mammals, insects and amphibians that reside nearby and benefit their local ecosystems through pollination, pest control and soil health. Sometimes a tree will die in a way that leaves it standing, or even confines part of the living whole to the afterlife while sparing other parts.
Snags and dead sections of living trees are attractive habitats to a variety of fungi and insects, who slowly break down the dead wood over years, making it soft and pliable. After five years or so, the wood becomes soft enough that birds like woodpeckers are able to chisel their way inside, feeding on the resident insects and making themselves a cozy nest at the same time.
Studies have found that woodpeckers rely on multiple nests throughout the year, and are constantly on the move depending on local weather and predator movements.
Keeping a robust collection of snags and dead sections on living trees helps these birds establish a foothold in the area, and are also nesting sites for a wide variety of other bird species as they age and change in composition. What grows up must eventually come down, and once this dead wood falls to the forest floor, it continues to feed and shelter the forest denizens of the area for perhaps hundreds of years.
Once a log has fallen, it immediately begins breaking down faster than if it was still standing. The side in contact with the ground soaks up water and begins its life as a fungal buffet, attracting a variety of wood-eating fungi. Some of these fungi create mushrooms that feed deer and other wildlife as the fungal body softens and breaks down the wood.
Hollow logs have been found to be key habitats for insects like bumblebee and wasp queens, who shelter inside to keep warm during the winter. Many other insects take shelter underneath bark as it slowly separates from the log itself. Mammals like chipmunks, squirrels and shrews also live inside of fallen logs, and use them as raised trails as they run throughout the forest.
Ground-nesting birds like ruffed grouse also nest inside logs, and male grouse also use hollow logs with appropriate acoustics to amplify the “drumming” noises they use to attract mates. As logs age they become very porous, turning into huge sponges that help retain water that the surrounding plants and animals rely on during dry times.
This moisture also attracts salamanders, who enjoy living underneath logs especially in the spring and summer. Each tree species tends to break down at different speeds, with hardwoods taking the longest to completely disintegrate, supporting the life around them for hundreds of years in the right conditions.
Brannen Basham is a writer and horticulturalist. Together with his wife, Jill Jacobs, he owns Spriggly’s Beescaping. He published his first book, “A Guide to the Wonderful World Around Us: Notes on Nature.” For more information visit www.sprigglys.com.