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.
https://maps.app.goo.gl/pJYr6qiZnMdVwLJS6
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?
That's a bit odd - why wouldn't wind blown non-sterile organic matter from the surrounding forest re-colonize the area?