From Wikipedia: "Most utility poles are made of wood, pressure-treated with some type of preservative for protection against rot, fungi and insects. 

Southern yellow pine is the most widely used species in the United States; however, many species of long straight trees are used to make utility poles, including Douglas-firjack pinelodgepole pinewestern redcedar, and Pacific silver fir."

All photos, except as credited to others, are copyright Emerald Canary.