These are christmas trees, which in oil field terminology means the assembly of valves that are placed on top of an oil or gas well to allow the roustabouts to keep constant flowing pressure on the production. Unlike the holiday Christmas tree, the oil field christmas tree (not spelled with capital letter) is small at the surface of the ground, but branches out at the top as more valves are added.

Photo is dated 1960.

Photo measures 10 x 8 inches.