Thank you for your question, Rachel.  The cause of the browning may be a lack of water, combined with higher temperatures.  However, there are several diseases that also infect this species, discussed here:  https://agsci.oregonstate.edu/sites/agscid7/files/horticulture/osu-nursery-greenhouse-and-christmas-trees/onn011001.pdf

You have a couple of options.  You can use the advice in the article about pruning out dead tissue, since it is dead, and water it more often next year.  Or, you could send tissue samples to the OSU Plant Clinic (https://bpp.oregonstate.edu/plant-clinic) for diagnostic testing.  Taking a wait and see approach will give you information about how it progresses--or not so much--next year.  Hope this is helpful.  Good luck!

Were you able to get my response?  We are launching a new platform and the system is a bit wonky yet!

Okay!