The pointer trees also known as water directional trees in Texas often have burl companion trees. These usually have the burl on the opposite side of the pointer trees where the available water source is the opposite direction. Because of their location to the water source, I have surmised that they usually represented the outer boundary limits of the campgrounds where all animal and human excrement was kept away from the camping areas....for example their personal horses tied up for rest or perhaps larger herds hobbled during the nighttime grazing and watch.