Right around Carver or Kingston, southbound travelers reach a transition zone—an ecotone—between the realm of Northern Hardwood Forest and the beginning of the Atlantic Coastal Pine Barrens. The composition of the trees becomes heavily pine and oak. The forest floor is littered with dry needles, and scrubby shrubs make up the understory.
The Howland Reaserch Forest includes rare forest of hemlock, spruce, and white pine—some trees so vast and old they proved already middle-aged when Thoreau passed through on his way to Katahadin over one hundred and fifty years ago. Howland was established in 1987 as a research site, and for the last twenty years, ecologists at the U.S. Forest Service and University of Maine-Orono have been quietly churning out groundbreaking data on carbon storage and sequestration.