A walk in the woods is often done to escape the complexities of human society that hound us all. The forest is a place of peace and supposed simplicity. But if observed closer the forest has an intricate complexity that is so elegantly carried out we don’t even realize it’s happening. Take that dead log lying beside your favorite trail. It’s just a tree whose time ran out and appears inactive. But what’s going on inside it is a key component in recycling nutrients to feed the trees of the forest and provide food and habitat for a lot of wildlife species.
The wildlife geeks call dead wood on the forest floor “coarse woody debris”, or CWD for short. It accumulates from various sources: wind, snow or ice storms, timber harvests, and tree death from old age or competition. It often starts out as a standing tree that dies, referred to as a “snag” (old logging term). During the decay process the snag provides important habitat for wildlife such as woodpeckers and squirrels. Eventually the snag rots enough to weaken and fall down. Once on the ground the wood is exposed to higher moisture from the soil and decay picks up in pace, and millions of microorganisms get busy breaking down and ingesting the woody material. These micro-beasties are food for invertebrates (insects, spiders, slugs, snails, worms, centipedes) that in turn feed small mammals, birds, amphibians, and reptiles. The food chain continues up to the larger carnivores and you get the picture. There are over 400 species of insects alone that enjoy the fool out of digging around in rotten wood for lunch and end up being lunch (okay, they don’t enjoy that last part). Besides providing protein, the downed debris provides nesting sites for those who like such a place. Slowly, the nutrients in the rotting wood is broken down and released back to the soil, which is taken up by the living trees and plants of the forest. It’s a slick piece of creation engineering to take death and turn it into life.
There is unending research that shows the importance of woody debris in and around streams to aquatic wildlife. But if you’ve ever fished for bluegill near a dead tree in the lake, you know this to be true. Woody debris bridges the gap between the soil and the plants growing on it, and is totally necessary for healthy forest ecosystems.
Some landowners I work with think dead wood on the ground is unsightly and needs to be cleaned up, but for wildlife in particular, it’s important to have around. And there are forests out there that don’t have enough woody debris, so if you own a patch of woods and want to know it it’s creating good wildlife habitat, give your local state forester a call.