How does Bernd Heinrich use imagery in A Year in the Maine Woods?

Examples of Imagery:

"Of all they built, only the stone walls, crumbling wells, and barn and house foundations still remain as visible reminders."

"As I look across the landscape and 'see' mountains rising out of the earth, being eroded again to leave plains, and then rising again while the continents drift about, the only permanence I see is in life itself."

"Nature provides the greatest entertainment on earth, and we had watched a flawless live performance that had been rehearsed on warm summer days and evenings for at least 60 million years."