Reminds me of the Gamma Forest at Brookhaven National Labs. From 1961 thru 1978 they irradiated a section of the pine barrens forest with a cesium-137 source just to see what would happen. It sterilized the soil and hardly anything grows there, almost 50 years later.
There's nothing unusual there. Typically natural forests grow out in stages, with different generations of trees replacing each other.
Because they actually killed off everything, the "older" trees are not propagating there because they are not adapted for that. That's also why natural forests have clearings that can last for a while.
What's unusual (or "unnatural") is that it's not just the macro level that was annihilated, but even the subterranean fungal network. Fire won't do that (unless the soil is very thin). Drought won't.
What is happening is apparently the entire cycle of repopulation of a food source for the most fundamental of ecosystem anchors.
What surprising is that this should be the equivalent of planting a garden with fuly sterilized soil. As someone else noted, why aren't wind-borne spores and nematode corpses revitalizing the subterranean ecosystem?
That is probably why you can see some low scrubby undergrowth in the Google Earth view, but nothing that needs to put down deep roots has yet returned.
If there's enough radioactive material and it is mobile enough (due to ground water or wind driven mixing) to stay near the surface it could sterilize any organic material that comes in faster than it can accumulate.
"An area of oak-pine wood was selected East of Upton, and a tower was constructed that could raise and lower a canister from underground that contained radioactive source material, allowing for controlled dosage levels that emanated in a radius from the tower. The canister contained Cesium-137, which would emit ionizing gamma radiation without making the surrounding area radioactive itself."
That 1967 documentary highlights lichen and clumps of grass growing there. I imagine the soil ecology has been devastated and failed to regenerate which is why larger plants like trees haven't been able to return
I'm guessing the distinct lack of Google Streetview on that circular bit of road nearby and the tracks implies a certain amount of resistance to access if you get off that dual carriageway to the west?
Brookhaven does classified research and access to the site is pretty restricted. The last time I visited there were guards with assault rifles at the gates. In comparison, Fermilab used to (and may still) let you walk onto the campus and wander about.
that seems pretty major exaggeration
https://bsapubs.onlinelibrary.wiley.com/doi/10.3732/ajb.0800...