Thanks for all the comments. The idea of historical research providing some context is certainly part of trying to get the most out of local photo opportunities, so I'll offer a little for the above photos.
The park in which I was hiking was once clear-cut, virtually all the trees felled to provide charcoal to fuel one of the largest and most important early 19th Century foundries in the US, and also held numerous small iron mines supplying the foundry as well. Among other things, the foundry was crucial to the Union war effort, casting artillery pieces for the Northern armies; it is now long gone, but the foundations remain and have recently been preserved in a park of their own. The second-growth hardwood forest is now quite dense, having had the better part of a century to reclaim the land, but if one looks remnants of the industrial era can still be spotted: the old railbed used to transport material is now one of the trails (you can see a bit of it in the third photo), some of the mine entrances are still visible, a few foundations of old houses remain, and many of the lakes were man-made to provide more reliable sources of water to the people living there (though the old dams are crumbling, but the local beaver population is taking over the job of maintaining them).