There can be numerous reasons for the browning including insects and/or funguses.  The most common reason however is winter burn and desiccation.  Evergreens do not go dormant meaning there is uptake by the plant in winter.  Water and nutrient uptake can’t happen in frozen soils and desiccation is the loss of moisture which comes from drying winds.  If the damage is mostly on the south side of the plant then winter burn is a good bet.  Rapid temp changes can also affect leaves and yes, salt could well be a factor as well.  Evergreens should be well watered going into winter if Mother Nature doesn’t do it for you.  This hydrates the tree as well as helps keep the soil warmer because wet soils hold more heat than dry soils.  There is no quick fix if winter burn is indeed the problem.  Recovery could take several years, especially if new buds were killed.  More help could come from a professional evaluation by a Certified Arborist, who at the least would give you a correct diagnosis.  You can find one or more Certified Arborists in your zip code at www.treesaregood.com  Click on Find an Arborist. Arborist evaluations are not expensive and highly recommended. Otherwise here are a couple of links to more on winter burn:   

https://hort.uwex.edu/articles/winter-burn/

 http://msue.anr.msu.edu/news/protecting_evergreens_from_winter_injury

 Good luck!