I suppose some trees might have very shallow roots.

In arid areas of California, plants need deep roots to get enough water.

Scotland is rainy and that particular place might be boggy or something where they have no need to go down.

There doesn’t appear to be any soil for the roots to go into.

My assumption would be that it’s a relatively new forest, the ground that was there previously has been removed, perhaps for peat, or burnt as part of forest clearing, and these trees planted on it. These things are standing because the roots are now intertwined like a giant mat.

Yeah was my first thought too! Was worried it was going to have its last bark…

Scotland is pretty rocky terrain in general, a significant amount of their forestry is on a fairly small amount of soil directly on rock.