I have never seen carpenter bees as they only extend into the southern parts of Canada.  I would love to see an active nest, but understand that they may become a nuisance in some contexts.

My cousin in Ontraio had a problem with carpenter bees and used the following excellent reference to manage them:

Common-sense Pest Control.  1991.  W. Oldowski, S. Daar and H. Olkowski.  1991.  The Taunton Press.  Nestown, CT.  ISBN 0-942391-63-2

Carpenter bees have a distinct preference for certain wood in nature; they do not like rotten wood, and will not make a nest in a live tree, preferring sound dead wood without bark.  Although the bees are solitary, a system of nest galleries developed by several bees working in the same area over a period of time can extend as much as 6-9 ft. winthin a piece of timber.

MANAGING CARPENTER BEES
1. Where carpenter bees are known to be a problem, keep exposed wood heavily coated with paint or varnish, or cover it with materials such as metal or fiberglass, into which the bees cannot tunnel.
2. Where damage is already underway, replace the damaged wood with painted wood or other materials that are not attractive to bees, or fill the holes with steel wool and staple on metal screenings after the bees have emerged.
3. If a pesticide is considered necessary, use one that is pyrethrum-based.  Plug the holse after treatment, or replace damaged wood with undamaged chemically protected materials.  Furthermore, benzaldehyde, which use to be used to drive honey bees from honey supers, is known to repel carpenter bees.  Almond oil essence that you use for cooking, contains benzaldehyde and may be useful in driving the bees away during the active season until physical changes can be implemented.

Adony