For years, arborists have been concerned about bees in trees because they nest in tree bark. Major guidelines for tree hazards list beehives and nesting holes as hazardous defects.
Before constructing their hives, bees must have a minimum of 8-meters clearance to successfully hang it from tree bark. However, the average diameter of trees is only 12 inches. If bees are successful in building their hive, this leaves little room for the wood to survive. Just as beehives present a problem for tree cavities, they also affect the bark of the tree.