Dead Trees

Trees offer a variety of services for wildlife, whether they are in a forest, a city park, or in your backyard.  Trees grow slowly and die slowly.  Each year, they flower, leaf out, and grow fruit throughout the spring and summer and then drop leaves and fruit each autumn.  Often, one,  two or more branches will die each year, even as new ones are being added.  As each part of a tree dies, habitat is not lost; it is transformed into use for a variety of wildlife.

A hole in a tree can be created by a variety of events: branches broken off by weather or animals, trees being impaled by other trees during violent storms, or punctures or cuttings from human activities.  Openings offer nesting sites for owls and flying squirrels.  Bark at the lip of a hole will start to peel away allowing bats and spring peepers to get underneath for shelter.  Small holes invite insects in, and woodpeckers searching for insect prey enlarge the holes.  When a cavity becomes large enough to kill the entire tree, it is often used by tree swallows for nesting or as a great place for honeybees to build hives.

Snags are dead trees that remain standing.  These offer birds of prey perches while they scan the areas underneath for small animals to hunt.  After the snag becomes too weak to stand any longer and falls to the ground, it becomes shelter for numerous species.  Mice and chipmunks use small holes to store food, raise young, and hibernate in for the winter.  Large hollow logs offer a home for skunks and bobcats.  Accumulated bark and leaf litter is a favorite place for toads and black rat snakes looking for a place to lay eggs.  Shade provided under fallen logs promotes a damp environment, a favorite place for salamanders.

As wood starts to decay, decomposers move in.  Fungi begins the process by breaking down the bark and returning the nutrients to the soil.  Millipedes, termites, beetles, and ants all feed on rotting, decaying wood.  Opossum, raccoon, robins and nuthatch find a treasure of insects and arthropods to feed on.  Earthworms and grubs help to mix all of the droppings around the fallen log into the soil through their tunnel building activities, constantly enriching the soil.

Dead trees are an important part of a forest ecosystem and can play a beneficial role in any habitat.  Consider leaving branches where they drop, or artfully placing them into your own garden habitats.  They provide shelter and food for many organisms, creating a rich and diverse community.  Species that directly use the wood provide food for small organisms as they break down the wood and are prey themselves for larger animals.  They release the nutrients trapped in the wood and enrich the soil in the process.  They create shelter by opening new holes and enlarging existing ones for additional plants and animals to occupy.  Next time you are out walking, gently turn over a log, and observe this wonderfully changing habitat.