- October 2, 2016
When a tree falls in the forest there are plenty of creatures who hear it and quickly begin to make use of the newly created habitat. The value of a standing tree is easily recognized –shade, fresh air, and fruit–to name a few. The value of a fallen tree, however, is less obvious. A closer inspection reveals a spectacular microcosm of wildlife engaging in critical ecosystem processes, like decomposition. And, these fallen trees may have habitat value rivaling that of its standing predecessor. Fallen logs instantly provide complex structures where a diverse range of organisms can find stable microclimates for nesting, denning, feeding, and food storageopen_in_new. From microscopic protozoa and magnificent mushrooms, to birds, amphibians, and megafauna, a decaying log is an active and exciting community. Let’s take a closer look.
As soon as a tree hits the ground and becomes a log the resources it provides begin to change. The bark will loosen and make great homes for insects, their eggs, and their larvae. Many birds, like woodpeckers and nuthatches, will take advantage of the increased easy access to the bug supply; and, can often be seen pecking through the bark along the length of the log, sometimes throwing hefty chunks as they search deeper into the decaying woody debris.
In dense forested areas logs serve as sunning spots, lookout posts, and display areas for birds. Male Ruffed Grouse (pictured above) will boldly perform their springtime drumming display on logsopen_in_new –the resonance from the dead wood helps make their presence known loud and clear. Ruffed Grouse, towhees, and other ground-nesting birds will make their nest under the raised end of log providing a close lookout while helping the nest to stay hidden and protected.
Small mammals, like squirrels and chipmunks, even mice, moles, and voles, will use logs extensively as runways and lookouts. They provide a clear pathway across a cluttered forest floor, or safe passage through the tunnel-like hollow portions. As the center of the log rots and hollows-out the resulting den can be used by fox, fisher, or larger mammals like coyote and black bear depending on the size of the logopen_in_new.
Logs in streams and ponds or along the shorelines of lakes and wetlands provide important habitat structures for the wildlife that live in those environments. Turtles and beaver will use them for sun perches, while fisher, mink, and many birds will appreciate the easy access to water and the improved hunting habitatopen_in_new. Under the water, these partially submerged logs provide important breeding habitat for fish, crustaceans, and hiding places for frogs and other amphibians.
On dry land and in arid climates, logs are both shelter and sunning platforms for local reptiles. These Green Anoles in Georgia change colors to blend in while they soak up some rays. The wood absorbs heat from the sun and provides morning warmth that these cold blooded creatures need to get going. Lizards, snakes, and skinks will gladly glean insects from the cracks and furrows and hide from predators underneath the log’s protective cover.
In shady woods, fallen logs retain moisture, decompose fast, and maintain a mossy coating that creates the perfect micro-habitat for dozens of species of salamandersopen_in_new. In the winter salamanders burrow deep into the ground to hibernate, but the rest of the year they rely on the environmental conditions and food sources provided directly underneath logs. Turn over almost any piece of woody debris in a temperate forest and you are sure to find one or more of these gentle amphibians.
Beyond shelter and structure for wildlife, logs provide substrate for fungi (like the honey mushrooms Armillaria mellea above) producing interesting and beautiful arrays of colorful mushrooms. Mushrooms provide a high protein food source for many of the insects, mollusks, and wildlife species that use logs for shelter or other habitat resourcesopen_in_new. Many species of mycelium are specific to certain types of wood and fruiting (mushroom-bodies) depends on specific environmental conditions. When mushrooms do appear a diversity of color and shapes decorate the forest floor. Fungal processes are part of decomposition, breaking down the wood over time and adding nutrients and structure to the soil.
A decomposing log can collect a host of seeds from the wind and from critters storing their winter reserves. As the wood breaks down it becomes softer, retains moisture, and acts as a growing medium germinating the seed bank stored within its cracks and crevices. This pioneer plant community may not have had the same chance at survival if it weren’t for these nurse logs on which tree saplings and other plants are able to take root in resource-competitive environments. A pile or stack of logs or large branches will also shelter young saplings from deer browsing, intense temperatures, and desiccation, giving them a strong and healthy head start.
The damp conditions behind peeling bark are very inviting for spiders and other beneficial insects, while pollinators, like butterflies and solitary bees, and their larvae seek residence in the drier parts to over winter. For long lasting structures with active habitat use, choose hardwood logs with the bark still attached. Sink one end a few inches into the soil to maintain some moisture and surround parts of the log with a few smaller branches or rocks to provide extra cover and improved habitat. Once your log is established and well used by flora and fauna you can carefully move these smaller branches or rocks to reveal the wondrous world of wildlife beneath.
Leaving downed logs and other large woody debris throughout a natural environment is incredibly important to plants, wildlife, and ecosystem processes. You can also add logs to your yards and garden spaces for an attractive way to increase the structural diversity, add contrast and define borders, and provide the wealth of habitat we’ve discovered these features to have.
Add a Log to your Map
First, find the log object to place it on your map. It is located in the Tool Shed under Third. Scroll to the right using the arrows on the toolbar that pops up to find the log object. Click it once to select it then click on the map where’d you’d like to place it and drag it open to the size you’d like. You can always change it’s size and position using the lock/unlock from editing box.
Double click on the log to add important data and show off your conservation efforts. You can give your log a name or title in Basic Information. Then click Characteristics to tell us about it. Don’t forget, you can also make comments about the bee house and upload pictures of it. We want to see your logs being put to use.