Hoping to return this thread to its "kinder, gentler" initial direction:
Roy, was there a certain period of time when the majority of these trails were abandoned? I'm guessing the main reason for "reclaiming" trails was erosion.
The Watermans'
Forest and Crag provides interesting reading about the history of trail development in the northeast. They suggest that major factors in trail abandonments were the triple barreled impacts of the 1938 hurricane, World War II, and the war-related closing of the trailhead hotels. They cite this especially in the abandonment of the trail network in the Rosebrook Range, near Crawford Notch. Other of the "Grand Hotels" maintained trail networks, some of which fell into disuse with the decline of the hotels, while others continue.
The Hale FW trail and the Bemis Trail were both built to service fire lookouts, and when the lookouts were closed, the trails fell into disuse. Other mountains also fit this pattern, I'm sure.
Conflicts with trailhead landowners may lead to the closing of a trail, such as possibly the Tuttle Brook Trail. The condo development at the lower Osseo Trail probably belongs in this catagory, too.
Logging has had dramatic impact on many trails, especially in the pemi. When an area is logged, trail markers are removed, and a maze of logging roads and trails will confuse any intrepid hiker. Extensive logging also makes an area less desireable to hikers. Logging still takes place in the WMNF, and I suspect the WMNF may rarely relocate a trail away from this activity. I suspect this is why the western end of the Three Ponds Trail was moved. I believe the WMNF does a pretty good job of avoiding hiker-logger land use conflicts.
I think it's fun to consider and study the rich human history of our "wilderness."
