I read in something I got from the extension service once that the biggest problem faced by most plants in Utah (including or especially lawns) is too much water. You didn't say how much or how often you're watering the pine, so I can't say for sure, but the fact that you're suggesting it as a posibility makes me thing it's probably part of what is happening.

When did you plant it?

How often do you water it?

When you first plant it, you should water it every day for about a week, then 3 times during the next week, then water it fairly deeply once a week for about a month. At that point, you want to water it deeply twice a month for the rest of this year. Next year (and after) water it deeply once a month. Also, after the first few weeks, the watering should be at the drip line of the tree.

I used to have a guide telling how much to water based on trunk size. I think it was 5 gallons per inch in diameter, once a month.