Reply to post by Peter Larson, on May 18, 2003 at 20:05:55:
First, I'm not an expert on tree diseases, although I am very interested. Many clues may help in answering a question about apparent disease in any tree. It helps to know the tree species (eastern or western white pine?), site conditions (especially if there is exposure to pollutants, such as salt, etc.), weather history (drought, excessive heat or cold, flooding?), and observations for known pests.
Tip browning can be caused by a number of factors, including water stress. It may be best to ask for advice from a more local expert, whether University Extension or arborist. If you know that de-icing salt is not used in the area, then that can be ruled out. If you find insects associated with the needles, have them identified to find out if they are cause for concern.
See the linked site and look up trees under Pinus to find white pines. There is some information on damaging agents, but not diagnostic information.