2. You're not going to solve overpopulation, which is the result of a growth trend, by adding a constant amount of land to the equation. If you capitulate and give up the forest, then eventually you're left with overpopulation and no forests.
3. The literal answer to your question would be to develop elsewhere in the world, or in space.
4 We need forests too, for our health and sanity.
TFR is synthetic based on population behavior (I.e. Not solely intrinsic, such as genetic).
My point is that there is a feedback-loop at work here. Educated women self-select against reproduction because the consequences are more obvious. But under-educated women still have high TFR-- they will need to hit hard boundaries (starvation, dieback).
I don't think the process of overpopulation is ending, just clamped.
From the notes in this article, (http://www.citizen-times.com/story/news/local/2016/11/08/box...) I get the impression that Sweeney bought the land a fair bit of time ago (perhaps when the real estate bubble burst as indicated in the article). The inspiration for this recent protection came from an eminent domain issue a couple years back where a power company wanted to run a power transmission line through his property.
There's more information about this here as well (http://mountainx.com/news/community-news/rutherford_electric...).
It would be interesting to get a more local perspective; my first impression though is its not completely walled off from the public (guided hikes and a 10K trail run are mentioned). As long as local opinion is relatively in favor of keeping things unspoiled I see this as a positive.
What happens a couple of centuries from now, when the Eastern Seaboard is overpopulated and we have 40,000 acres of land being held in limbo by the Sweeney Foundation?
Having this land being preserved in its natural splendor for future generations to enjoy is a worthy and noble goal, but what happens when we need housing more than we need forests?
Granted, I know this is only a small portion of the land in North Carolina (62.5 sq. mi / ~53,800 sq. mi or roughly 0.12%), but if 2-3 billionaires every generation pay to keep land pristine and untouchable forever, it'll add up over the centuries.
Just something to think about.