Question
Landscape crew has damaged the bark by the base of my new orange trees with weed wackers or a lawnmower.  I bought plastic sleeves to cover the trunk area to prevent further damage.  Do I need to apply any wound dressing or paint to help heal where the bark is gone?

Answer
No just cut any loose bark off and the tree should heal by itself. I would put mulch around the tree so the "wackos" can not get near the trunk. use not more than 3 inches deep of organic mulch. To keep borers from entering the wound I would spray the wound with an insecticide called Merit. This will prevent attack for 3 months giving the tree time to start the healing process.