The 2 types of bone markings being identified would be the opening on the occipitomastoid suture in which the internal jugular veins would travel to carry the blood from one's brain to the heart and the Mandibular condyle of the mandible that would then form the temporomandibular joint.
Im not really sure about the water, other than the trees wouldn't be absorbing it so there would be extra? But a huge amount of trees like that produce a lot of oxygen, so there would not be less oxygen in the environment. Hope this helps!