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The Very Core of Forest Ecology
7/22/2007 The Washington Post By Andy Mead In dense, trackless woods just west of here, researchers are looking for remnants of what they call "the original equipment." They mean old trees, trees that might have been saplings when Daniel Boone wandered this way. "We need to find these areas because of what they can teach us. These could be the core areas in which genetic diversity has been protected," said Neil Pederson, an Eastern Kentucky University biology professor who describes himself as a "forest ecologist." Pederson recently organized a group tentatively called the Kentucky Old-Growth Forest Society. Its goals include bringing attention to old-growth forests and trying to find more. Eastern Kentucky is heavily forested, but most of those woods have been logged and have come back two or three times. The largest exception is Blanton Forest State Nature Preserve, where 2,300 acres have never experienced a chain saw. Although its trees have been standing for 300 years or more, Blanton was "discovered" in 1992. There is also Lilley Cornett Woods, where half the 500 acres is old growth. Pederson, who arrived in Kentucky less than two years ago, is convinced that there are other pockets out there, waiting to be found. Last month, he and a group of students slipped through a narrow gap in a cliff in the Daniel Boone National Forest in search of old trees. What they found looked promising, but it will take months of analysis of pencil-thick cores from the trees before they will be able to say whether they found an old-growth patch. Pederson and the students went to a spot where Kacie Tackett, an Eastern Kentucky University graduate student, is working on a thesis on forest disturbances in the area. She is looking at disturbances of the past but also anticipating the future. The many large hemlock trees in the area are expected to die in the next few years as an insect that kills the trees sweeps through. The area is dominated by the hemlocks and large beech trees, with a sprinkling of red maples, white oaks, big-leaf magnolias and smaller umbrella magnolias. The biggest trees on a steep slope are about two feet thick and 70 feet tall. On flatter land, some trees are more than 100 feet tall. But the area looks nothing like a grove of redwoods, which is perhaps how most people envision an old-growth forest. This scene is much more chaotic. There are standing dead trees among the living and plenty of trees that have fallen and are slowly returning to the soil. The ground is covered with lush ferns and a thick layer of leaf mold -- a sign, Pederson says, that exotic earthworms have not reached these woods. Most types of earthworms are not native to North America so their presence in a particular area usually means people brought them there. And the only stumps bear the marks of beaver teeth. That, Pederson says, is a good sign that the woods might be old growth. Another sign: mounds of dirt beside pits, an indication that a very large tree once fell over on the spot and nothing has happened since then to level the ground. Beech trees seem to attract carvings on their smooth barks. The beeches at the first place the researchers stopped had not been carved on. Later in the day, they found a beech with "1978" cut into its bark and an older carving that might be "1902." What impressed Pederson most was all the dead and rotting trees. The standing snags are used by birds and animals, he said. Logs provide shelter for various animals and are like a time-release capsule returning nutrients to the soil. "This is what old growth is really about; it's about the dead trees," Pederson said. "A lot of stuff dies in an old-growth forest, compared to a 20-year-old managed stand." As for the live trees, Pederson said you cannot tell much about their age by looking at them. A tree growing in poor soil or heavy shade can live for a very long time without getting very big. That is why he uses dendrochronology -- the study of the past using tree rings. The borers that extract the cores make interesting sounds that vary with the type of tree and its health. But taking the long, narrow cores does no permanent damage, Pederson said. The cores will be glued into a holder, then sanded with extremely fine sandpaper so the rings can be examined. That involves more than just counting. The size of the rings can tell when there were droughts or when insects attacked. By coring several trees from the same area, the researchers can tell whether there are "missing" rings on a particular tree. That happens when a tree for some reason does not add an annual ring. Studying the rings also can tell a lot about whether the area has been logged. If most of the older trees are 130 years old, Pederson said, that will suggest the forest was logged 130 years ago. If the older trees are of different ages, but all show signs of a growth spurt a century ago, that might show that some trees were cut then, leaving more room for the survivors. If most of the large trees are very old and of various ages, that might mean they are old growth. Studying old-growth forests also can show just how long a particular species can live, which is valuable information as forests are increasingly managed, Pederson said. And even if the research proves the Laurel County woods are not old growth, Pederson said, they are old enough to deserve protection. Pederson said people need "to start thinking about protecting the 120- to 150-year-old forests because in 40 or 50 years, they'll be 200 years old." |