Personally, I do not put a lot of stock into random rubs. It just means a bull was there at one time. Rubs are done by bulls for various reasons. They will rub to remove velvet, to challenge or intimidate another bull, to display for cows to come their way, they rub to attract & size up other bulls but not looking for a fight, they rub as their testosterone levels rise & are feeling their oats, this is one of the most common. Those are the rubs I look for if any.
My favorite ones where I will plan an ambush is where the rubs & tracks are fresh & spread along a trail for a good 1/2 mile. Bulls will do this with or without cows, meaning some rubs are by the herd bull & others by satellites as they follow this herd around, they do this as cows show signs of estrus! Bulls can become restless as they await cows to be bred, one of the things they do besides bugle is rake trees/brush for no apparent reason other than restlessness. It is quite common to find these trails where multiple or single bulls use these trails from feeding to bedding & vice versa. You will find that bulls will rake a tree here & there while on these trails up & back. Over a course of a week or three multiple rubs will take place along these trails showing consistent fresh use, this is elk using the area at present! These types of finds are much better than a random rub found throughout the woods.
ElkNut1