The great cedar had lived to be almost 500 years old. No longer did a person have to get a crick in the neck straining the eyes to see the uppermost branches, for it now lay in ruin upon the forest floor. The massive sprawling heap made the forest look messy. Should it be cleared away to make room for new saplings? But wait! What’s happening in the tiny spaces between the wood fiber? Microorganisms are softening and opening up the wood. Decomposition has begun! What is decomposition? Is it simply the time consuming process of a dead tree crumbling away to eventually become soil for a new tree to sink roots into? Or could it also be full of lively rooting, burrowing, and scurrying activity? Let’s take a look!
The first group of animals to inhabit the tree are wood eating insects that eat the fallen tree and open it up to the outside world so that nutrients can begin to move around. These are the flathead and longhorn beetles, carpenter ants and wood-tunneling mites. These insects create pathways for more microorganisms such as bacteria, yeasts and fungi. Next come the animals which eat these microorganisms; predacious mites and scarab beetles. All these animals work on the fallen tree and reproduce for many, many years. Soon the wood is opened up and begins to break apart. It is becoming rich with phosphorus and nitrogen concentrations that are increased as the wood rots. These nutrients are important for the growth of new plants. So our next group to inhabit the tree are live plants such as moss, western hemlock, dogwood, fern and wood nymph. The plants root in the wood as it is opened up by the insects and microorganisms.
Predators enter the fallen tree when there exists an abundant food supply and an easy way to get inside. Mites, spiders, centipedes and salamanders roam and hunt in the passageways prepared by the other insects. Next come the animals that feed on dead plant and animal material and animal droppings: millipedes, isopods and earwigs.
With the aid of these larger creatures that break up plant and animal matter, most microscopic bacteria are able to decompose from a hundred to a thousand times their own weight every day! Fungi rootlets are so profuse that there are two tons of it for every acre of soil and logs! Red-backed voles eat the fungus and spread it to new places as they travel.
All of these populations become food for even larger vertebrate predators. The piliated woodpecker and other birds frequent the fallen tree looking for wood-boring insects to feed on. Flying Squirrels feed on the fungi and lichen. Pine martens and owls eat the flying squirrels and voles, and bears frequent fallen logs looking for one of their favorite treats - ants.
It appears our fallen tree is not just a pile of debris cluttering the forest floor, but a maze of plant and animal interactions that houses an entire ecosystem. Over a period of hundreds of years, armies of organisms, more than we can imagine, work on the fallen tree. 20,000 different species can live in one log! In the process of sustaining their own lives, nothing is wasted, and new life is given to the forest. Give yourselves a hand for playing an important, supportive role in “Up The Down Tree House”!