Fort Saskatchewan,Alberta is using radio frequency identification to track the maintenance of its city-owned trees.

By reading passive RFID tags attached to the lower limbs of trees staff members not only can update city records regarding maintenance status, they can also access details about when the tree was last watered or pruned, as well as how and by whom.

Read the entire article.
http://www.rfidjournal.com/article/view/8397/1