Honeybees in tree trunks or hollows often cause recurring problems. Getting rid of the bees in a tree trunk yourself may present a tremendous challenge. An established beehive in a tree trunk may consist of 5,000 to 20,000 bees. Normally the cost of equipment, in addition to the time you take to learn how to accomplish a successful removal with exclusion to keep the bees from returning far exceeds the cost of paying a bee removal specialist.
Bees within tree trunks can be removed alive by trap-out. After getting rid of the bees from a tree trunk, the honey scent can linger, attracting new bee colonies in search of a suitable home. To keep this from happening, the tree hollow can be filled a filler. If the hollow is large, the trunk can be filled partially with some crumpled newspaper, and next with expanding foam. Bees may have more than one opening even if it's small or the bees have sealed it off with wax.
It is quite common for a curious rodent or critter to chew through the foam, re-creating a hole for bees to move back in! To keep this from happening, prior to capping off the tree hollowing with expanding foam, a pre-cut galvanized non rusting screen can be placed on top of the foam.
Bees in tree trunks should not necessarily be taken lightly, an associate I worked with for a short time, told me about how her grandfather was attacked by bees that were living in a tree. At a young age he and his brother were driving with her grandfather on their way home (many years before she was born), when the tire got a flat; the vehicle swerved and hit a tree. From what she explained her grandfather got injured and didn't make it out of the car, the bees in the tree went into defense mode and he was stung many times before the paramedics arrived.
Caution should be taken when bees are removed alive by beekeeper or killed by an exterminator, when in public areas or where there are pedestrians crossing encase an individual is allergic or encase the bees are being exterminated and become aggressive.
Hornets nests may also be found in tree trunks. Hornets are an effective method of organic gardening and are seen as healthy for the environment. Hornets can have a nasty sting and sting repeatedly without losing their stinger. Hornets will typically sting only when highly provoked or when protecting their nest. Stings usually happen by accident. These seasonal critters abandon the nest in the winter and return in the spring to nearby areas.