Buck rub on trees for a variety of reasons.One is to strengthen their neck muscles for the upcoming breeding season.Another is to lay scent to let other deer that he's in the area.Some people believe that they rub to remove the velvet.Other deer will rub the same tree,also.Just remember-big bucks rub big trees.As for scrapes-that's another sign-post deer make.A buck will scrape out an area by pawing at the ground.Then he pees in the dirt.When you find a scrape,look for a branch over it that is chewed on.That's the sign of an active scrape.Other deer will also use this scrape,too.It's all about communication between the deer in that area.There's more to it but these are the basics.