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The Forest Floor The “earthy” smell of the
forest comes from the Right at the bottom of the food chain lie the decomposers, which mechanically and/or chemically break down organic matter. And they do it exceedingly well here in our moist forests, especially in the warm summer months. Bacteria, fungi, and a combination of the two (a weird little microscopic family called actinomycetes) are the three primary decomposers.When dead plants or animals rot, they are being broken down by decomposers, and their nutrients are returned to the soil. The animals of the forest contribute to the decomposition process by breaking plant matter apart with beaks and claw’s and by eating, digesting, and depositing the chemically treated organic matter. Scavengers such as coyotes, ravens, earthworms, maggots, and millipedes, are especially helpful in this regard. Still, the vast majority of decomposers are the truly tiny bacteria and fungi. If it were not for decomposers, hiking on the Four Soldiers Path would become a mighty challenge, given the hundreds of feet of dead mammals, birds, insects, tree branches, bark, leaves, and grass. But, then again, we wouldn’t be here to enjoy it all, because plants would cease to grow, animals could not eat, and eventually life on earth would stop. That’s how vital decomposers are. Bacteria are the smallest living organisms, and the most numerous of decomposers. They make up 90% of the billions of microorganisms typically found in one gram of forest soil. Bacteria can thrive in any environment; they can be found in the cold Antarctic wilderness, in the intense heat of a steamy geyser, or in the acidic contents of your stomach. They will eat things as diverse as an animal carcass or an oil slick on the surface of the ocean, and they often produce methane as a byproduct. Methane, like carbon dioxide is an important greenhouse gas. Decomposers, therefore, play a major role in regulating the temperature of the planet. Fungi, another decomposer group, are simple organisms and include molds, yeasts, mildews, and mushrooms. Next to bacteria, fungi are the most efficient decomposer organisms because they break down wood, enabling bacteria to continue the decomposition process.Molds are responsible for much of the rotting that takes place in the forest. Actinomycetes are a form of fungi-like bacteria that form long filaments that stretch through the soil. Actinomycetes are the primary decomposers of tough plant tissues like bark, paper, and stems. Soil’s earthy smell is caused by actinomycetes at work. They are especially effective at softening up the tougher plant and animal materials found in the forest. The forest fragrance is particularly noticeable when moist air increases the sensitivity of the nerve endings in your nose that detect smell. Lichens provide another adventure in decomposition. “Alice Algae and Freddie Fungus took a lichen to each other.” You may have heard that saying somewhere along the line. It reminds us that lichens—the greenish, yellowish kind of matted and crusty stuff you see clinging to rocks, hanging from spruce trees, or poking up a tiny bit from the ground—are the result of a symbiotic “agreement” between fungus and algae. Lichens are able to colonize bare rock and even chemically break it up into nutrients and tiny grains, leading to the production of soil. Little bits of lichens were, therefore, among the very first organisms to thrive here in Randolph, blown in on the wind just after the most recent retreat of glacial ice, 12,000 years ago.
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