Personification is a literary device that consists of associating human attributes to an object, animal or idea. The lines of the excerpt that contain personification are the following:
"The farm buildings huddled like the clinging aphids on the mountain skirts, crouched low to the ground as though the wind might blow them into the sea". In this line, the farm buildings are developing human actions such as "huddling" and "crouching".
"Five-fingered ferns hung over the water and dropped spray from their fingertips". Personification is used in this line because the ferns are mentioned as having fingers.
"The high mountain wind coasted sighing through the pass and whistled on the edges of the big blocks of broken granite". The wind is carrying out the human actions of "sighing and whistling".
"Gradually the sharp snaggled edge of the ridge stood out above them, rotten granite tortured and eaten by the winds of time". The human characteristics of "rotten" and "tortured" are attributed to the granite and the winds developed the human action of "eating" the granite.