It's well known in protohistory that most of the religious sites were wooded, both with idols and altars of wood, but also in the forest itself in special place

It's well known in protohistory that most of the religious sites were wooded, both with idols and altars of wood, but also in the forest itself in special places such as groves. The romans destroyed most of it, and later the christians (but I repeat myself). So I think gp is just reiterating this. Here in America our high country and high country desert really make us lucky for having close to surface access of ancient things, makes archaeology and paleontology much easier.