My friend has a very mature white pine tree and has recently diagnosed it with a white pine beetle infestation. Is there anything one can do to save the tree?
There appear to be several types of pine beetles depending on where your friend lives. If the tree is dying at the top, it may be the result of the white pine weevil (Pissodes strobi), a 1/4 inch long reddish-brown beetle with white spots. Pruning can help control the pest. This advice comes from Health Canada:
Pruning infested trees can be an effective control for ornamentals or small plantations if it is done as soon as possible after the first signs of infestation are noticed, usually when top wilting is first noticed. Prune close to the topmost unaffected whorl of branches. Immediately burn or destroy the pruned branches and leader stems to prevent weevil emergence.
After pruning out the infested leader, choose a strong lateral branch in the top that coils or spirals (this is called a whorl) and train it in a vertical position, tying to a stake that is secured along the upper part of the trunk. Check regularly that the ties do not damage (girdle) that stem or the trunk, as it may take a few years before the stake can be removed. Other lateral branches on this top whorl should be removed if they appear to be competing with the selected leader.
Band tree trunks and the base of leader stems with a sticky tape or a sticky substance applied to a band. Do not apply sticky substances directly to tree bark, because this may prevent adult weevils from reaching the leader stems.