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6. The Future of the Maine Woods: What Will Maine Forests Be Like in the Year 2100?
- University of New Hampshire Press
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6 | The Future of the Maine Woods What Will Maine Forests Be Like in the Year 2100? Change is an inherent characteristic of all landscapes and future change is inevitable.—David R. Foster and Glenn Motzkin, Northeastern Naturalist (1998) View from a Maine Woodlot Janet McMahon and Chris Davis have lived on their 100 acres in Maine since 1983. Their land stretches from the shoreline of the inner reaches of Muscongus Bay to nearly a mile inland, encompassing a wide range of naturalcommunitiesandhabitats .Mostof itiswoods,buttherearealsofields, an orchard, stonewalls, tidal flats, and, of course, their house, barn, and lawn.Theecologyof theirlandhaschangedconsiderablysincetheysettled here. The forest used to be mainly balsam fir and red spruce. Fir has been decimated by an aphid-like insect, the balsam woolly adelgid, accidentally introduced from Europe in the early 1900s, and spruce has experienced a slow decline. Red oak and ash are now the major tree species. Alien honeysuckle has multiplied, its seeds and roots apparently spread inadvertently along the dirt road by snowplowing. Moss is creeping across the lawn and roof, probably a response to the increased rainfall over the past couple of decades. This has also led to conversion of trickling temporary streams to permanent ones. New animals reside in the woods. Janet and Chris regularly hear the unmistakable repeating call of the northern cardinal, 190 t h e ch a ngi ng nat u r e of t h e m a i n e woods an uncommon presence until recently. Wild turkeys, extirpated from the stateintheearly1800s and reintroducedinthelate1970s,havebecomewell established. Opossums, in their inexorable march north, have crossed the Kennebec River into the area. The absence of ticks used to be one of the great benefits of living in this region. Now, they are common. Accompanying these biological changes, the seasons have shifted. In her work as an ecological consultant, McMahon regularly carries out aerial photography. She used to fly in the third or fourth week of May, when individual tree species could be distinguished by the timing of leaf out and the characteristic hue and texture of their spring foliage. She now must be in the air one or two weeks earlier to photograph the landscape at the right time. The same goes for the fall. It used be that McMahon would have to put her tomatoes on the porch to complete their ripening; they now ripen without such nurturing. At the nearby Watershed High School in Rockland , where she teaches science courses, McMahon had students interview residentsolderthanseventyabouthowthelocalenvironmenthadchanged. Themostcommonobservations:wetter,lesssnow,Japanesebeetles,earlier planting, and ripe tomatoes. The Future: Changing Environments, Changing Forests The McMahon-Davis woodlot is a microcosm of the changing nature of the Maine Woods. The underlying physical environment and the associatedbiotahaveshiftedinthelastseveraldecades .Accordingtoawiderange of models, these changes will accelerate during the rest of the twenty-first century. The causes of these transformations are complex; the driving forces do not act in isolation, but instead interact in ways that can amplify the impacts. Our understanding of these dynamics has progressed considerably , but key uncertainties remain. The goal of this final chapter is to lookforwardanddevelopprobablescenariosforthefutureforestsof Maine based on the best science available today. We evaluate four sets of pressures that are most apt to recast the state’s ecosystems: acid rain, invasive exotic pests, land use, and climate change. These forces act on species and ecosystems by altering the fundamental factors that determine how well individual organisms survive, grow, and reproduce. Such alterations will favor a different suite of species and communities than occur in the state today. Acid rain affects the levels of nutrients and deleterious chemicals in precipitation and soil. Some of the newlyarrivingalien plants,insects,anddiseasesinthestatebecomepotent [54.196.248.93] Project MUSE (2024-03-29 12:03 GMT) t h e f u t u r e of t h e m a i n e woods 191 competitors, predators, and pathogens, respectively, of native herbaceous plants and trees. Land use modifies the frequency, intensity, size, and type of disturbances, which alters the availability and distribution of resources required by organisms. Climate change shifts the temperature and moisture regimes governing the success of organisms and the set of species capable of persisting within a site. These four sets of forces, then, portend fundamental alteration of the ecology and character of the Maine Woods. Forecasting is a difficult and tricky job, and we do not take it lightly. One of the most common quotations accompanying ecological prognostications these days, attributed to the physicist Niels Bohr, is that “Prediction...