I have had a ponderosa pine in my yard for the last 4 years. It has done remarkably well considering the zone. We have had snow the last two winters that nearly covered the tree. (it's about 6' tall) I first noticed the needles turning brown and the nurseries said it was probably dead. Well, it started sprouting new tips in the spring and seemed to be doing ok despite the needle loss. This past winter I wrapped the trunk loosely with burlap hoping to prevent sun scald. I trimmed off the smaller branches that had no needles. This past spring all the needles turned brown again. It seems there is new growth again on the tips. What care can I give this tree to prevent this from happening? I'm not sure how long this can continue before it does kill the tree.