I know he is a biologist but there is absolutely no way to 100 percent say that small bucks cant rub big trees before a mature buck does. There is no way to prove that. At all
Numerous studies have been conducted on buck rubbing behavior. Although it is impossible to say young bucks never
initiated rubs on large diameter trees, it would not be the norm, nor common. Rubs on large diameter trees are almost always initiated by older bucks, although even a 2 1/2 year-old will initiate rubs on some pretty big trees.
From my research, I found that rubbed trees the diameter of a Coke can were very indicative of the population of 2 1/2+ year-old bucks in the area. The more trees of this size rubbed in the area, the more 2 1/2+ year-old bucks in the area.