I grew up (mostly) in an old farmhouse in Delaware. The three foot thick stone walls that make up the core of the house are probably 200+ years old, and from the basement, you can see that the main floor is supported by whole, rough-hewn tree trunks. The farmland was bought up and developed before I was born, but field stone walls and small building foundations are still present, scattered in the surrounding acres of private and state land.
Mirroring a century-long trend that has occurred throughout the Eastern U.S., the original farm was abandoned and now-maturing secondary forests grew up in its place. The U.S. now has more forest than anytime since European colonies were established.
The forest on and around my parents' property is in decline. The suburbanites have been neatening up the woodlots that snake between all their plots, cutting down ugly and dangerous trees and preventing the re-establishment of many seedlings. Many of the largest trees are falling now. The pro arborists say the giant boulders half-hidden in the soil compromise the trees' hold, and I imagine the loss of their neighbors increases windthrow.
Woodlots are great for anyone with more than about a quarter acre of land because they look nice with almost no maintenance. Lose too many trees, however, and the sunlight brings up chest-high weeds and brambles and you'll have to fight them every month until new trees establish a canopy or you give up and plant a lawn. I pointed out to my parents that one corner of their yard was a few trees away from being in this position - and if they wanted to keep a forest there, they'd better get a bunch of seedlings established right away - especially since this rocky, sloped corner will dry out fast when the sun starts hitting it.
Luckily, the remaining giant trees in the neighborhood litter their yard with seeds and there are oak, hickory, maple and tulip tree seedlings everywhere. Thankfully, the long-term scourge of Alianthus is pretty much gone. Surprisingly, there don't seem to be any beech despite the extent to which they dominate the local forests. When I'm home in the summer, I'll walk my dad around the yard so he can tag the nice seedlings for transplant into the remaining woodlot.
I'm very enthused about tulip trees (Liriodendron) right now. It's a nice native tree in the magnolia family that's strong, tall and grows absurdly fast. That picture shows a tree that's just a few years old! My dad transplanted it there as a tiny seedling maybe four years ago and it's already several inches dbh. Thankfully the deer don't obliterate them either, so he's been able to move a bunch more into the open spots, along with some slower-growing oaks and hickories.
With a little luck, they'll be well on their way to closing the canopy before the remaining old trees finally rot out.