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If I should die before I wake Worms, water, sun will have their way So when radishes and corn you munch – Lee Hayes, folksinger The forest floor in McDonald Creek Valley is a giant compost pile. Because so little sun gets through the canopy of cedar and hemlock, the major contributions of energy to this area are the old trees which finally die and fall to the ground. Before they fall, they usually stand for many years as giant snags, providing homes to woodpeckers, flying squirrels, owls, swallows, raccoons, porcupines, fishers, pine martens, bats, chickadees – the list is long. Carpenter ants, who leave sawdust piles at the base of the tree, dig tunnels through the wood, weakening the tree and providing food to pileated woodpeckers. Horse-hoof and turkey-tail conks (more fungus) dig their own mycelia into the tree while it still stands. When the big trees fall, there is an orderly progression of plants and animals who feed on the death of a tree, and give life to new trees in the process. Here, and everywhere, the “secret of life” is death, and the process is decay and recycling. In the cooler northern climates, most bacteria do not have a long-enough growing season. Decay is the job of fungus, and on logs this size, it might take 200 years. Once the log is down, the demolition team of beetles moves in. The larvae of long-horned beetles (their antenna are longer than their bodies) bore tunnels under the bark. They scrape the wood so hard that a listener can hear “crunch, crunch, crunch” from 50 feet away. Each species of engraver beetle leaves behind a distinctive “gallery” pattern of latticework. Ambrosia beetles bore straight to the heart of the log, turn right around and graze on the fungus which invades the tunnel. Pinhole borers dig tiny holes and flathead borers dig wider ones. Millipedes, ants, mites, spiders, even amoebae – all make their way into the log right behind the beetles. In an average log, 20,000 species will eventually call it home! These places are melting pot cities, with some of the greatest biological diversity on earth. In the hemlocks, one of those species is – hemlock. New seedlings find the body of their ancestor a perfect place to grow. Often, their roots follow the contour of the “nurse log”, arching down to the ground, long after the log is gone. Meanwhile, the new tree starts a “meaningful” relationship with the fungus in the ancestor log. Most important, of course, are the trillions of fungal mycelia. The sweet smell of rotting wood is the smell of fungus. It is over, around, in and through everything. It softens the wood and makes the log available to salamanders and red-backed voles. The voles -- a mouse with short ears and tail – are specialists in this kind of forest. They eat 95% fungus, at the same time spreading the spores (seeds) of the fungus everywhere. This system is tightly organized chaos, and everyone has a critical role. This system is protected in Glacier National Park. |
Last updated: February 24, 2015