Did you know that even in death, trees still have a lot to give to the environment? Dead trees, also known as “snag” or “wildlife” trees, continue to contribute food and shelter to hundreds if not thousands of animal, plant and fungi species long after their lives end. These great bones of the forests become worlds within worlds, fostering new life and biodiversity as they slowly return to the soil.
At the base of the snag tree food web, you will find decomposers, the industrious creatures that mine the deadwood and bark, unlocking the vital nutrients within. Very often the pioneer decomposers in snags are fungi, which through their spreading hyphae and mycelium make the initial incursions into the dead or dying tree, reducing tissues to their constituent components, mainly lignin and cellulose. This initial decomposition sets the stage (or table as it were) for many more players, like insects and their larvae, worms, plants and bacteria ready to colonize and consume the veritable smorgasbord that is the snag. In some ways this may seem like a typical ecosystem turned on its head- fueled by death instead of the producers harnessing the light of the sun.
With the arrival of small organisms, larger creatures invariably follow. With a readily available food source now inhabiting the snag tree, amphibians, reptiles, mammals and birds will be next to arrive. In most cases aided by very special ecosystem engineers- bird species of the family Picidae, better known as woodpeckers and their relatives. The woodpecker’s strong beaks not only enable them to extract invertebrate sustenance from the snag, but to carve out cavities to reside in as well. These cavities are then repurposed by hundreds of species of secondary cavity nesters (animals that require tree cavities to nest and live in but cannot make them themselves), including screech owls, various songbirds, bats, kestrels, racoons, opossums, flying squirrels, kingfishers and ducks such as wood ducks and hooded mergansers just to name a few.
Sadly, snag trees don’t align with most people’s landscaping sensibilities, and these wildlife havens are regularly cut down on residential property. The ramifications of the removal of what many people view as an eyesore are far reaching, depriving many species of both food and a place to live. Next time you have a wildlife tree on your property that doesn’t endanger your house or other structures, please consider leaving this valuable natural feature for our local wildlife.
By Jake Kommer