This is an easy woodworking project to make carpenter bee traps out of 2x4 or tree branch scraps & a jar using minimal tools. It gives the bees a nice chunk of wood with premade holes that lead to a glass jar. They land on the outside of it, climb up into a tunnel that leads up at about a 45° angle to another that goes straight down through a jar lid into daylight, & they're stuck in the jar until I get around to emptying it. I've never seen one find its way back out.

Carpenter bees look similar to big bumblebees & they're pretty innocuous for the most part. Like most bees, they're an important part of the ecosystem so I don't go out of my way to kill them unless they're causing a problem. They certainly do when they build their nests in my buildings. I don't like using pesticides & many aren't particularly effective since the bees don't eat the wood they're boring into. They just crunch it into sawdust & shove it out the hole which is why they'll bore into treated wood. Effective pesticides are pretty nasty & only work for a short time, so I think the best way to stop them is to plug their holes & trap them. These are the plans for a couple of different traps; one using 2x4 scraps, the other a bit of tree branch.