Clear the trees.

Tree stump, remover.

Just a thought, a way to remove trees in the way of excavations, just use a stick or two of dynamite, blow them up.
This was the method used, on an excavation back in the sixties, on a site just West of Arundel.
Seems a good idea to me! Saves a lot of digging.I can see Con Ainsworth there now, “all stand back light the fuse” “BANG”. OPPS!