Hi,  It looksl ike you have either a Sequoia Pitch moth or a boring insect affecting your pine. If it is one of the boring insect/beetles then it will be difficult to manage.  Are you able to send a photo of the entire tree?  In general Scotch pine are not real adaptable to the high desert so always under drought stress due to the lack of above ground humidity (watering cannot remedy this).  Also, feel free to call me at the number below to further discuss.   Thanks 

Thank you for your response. Here are two photos of whole tree. 

Hi, After seeing these photos, I think that the tree is too far gone. I would recommned removing it. If you decide to replace it I would not recommend replacing it with another Scotch PIne. You can check out some of these other conifers if you want another pine or spruce tree, : https://catalog.extension.oregonstate.edu/em9136

Looks like you have irrigation available if you decide to add another tree.  

Thanks,  

Thank you. We’ll take your advice and remove the tree.