Carpenter bees (mostly the genus Xylocopa) are often pests because they
bore into wood. The female bees have very  sharp mandibles and bore a
tunnel to accomodate themselves and their nest cells. Within the tunnels
they provision the cells with pollen and nectar in a ball or loaf. They
lay a single egg on each mass of provisions and seal up the cell. The
egg develops through several larval stages and most likely stops in a
"pre-pupal" stage in our region for the winter. In spring, development
resumes, metamorphosis takes place, and the new adults emerge (males and
females) in the summer. Mating probably takes place soon after the adults
emerge. The cycle then starts again.
The bees are remarkable in that the females, when in high density in
particular pieces of wood have an uncanny way of not boring into each
others' tunnels. Perhaps they sound the wood as they bore. Also, in
planks, their tunnels will not emerge out of the back as the bees
will angle the tunnel down. Often the tunnel is shaped like an upside
down "L". I suppose the shape offers protection against water entry
during rain as well.
The species of Xylocopa which extends into the NE USA and even into
Southern Ontario is X. (Xylocopoides) virginica virginica (Linnaeus).
There is another subspecies of this species in the SE and another species
X. (Schonherria) micans Lepeletier in the SE.
 
I hope that answers the biological questions. Getting rid of them is another
matter and certainly difficult without chemicals or lots of effort. You
could let me know what your approach might be.
 
Cheers, Peter Kevan, U of Guelph, Ont. Canada N1G 2W1