An Antidote to Beer Chang?

Those who have caved in Thailand may have come across sticks that have been rested on end by Thai visitors under overhangs and boulders.This ‘stick standing’ can be found throughout the country;  a particularly fine example can be seen in Tham Jaeng in Loei.  It is obviously done for pseudo-religious reasons, but I had been unable to find an explanation for this behavior and it isn’t mentioned in Christophe Munier’s ‘Sacred Rocks and Buddhist Caves in Thailand’.