Hello,

The pictures are dark, even when I enlarge them, so it is difficult to see needles and stem clearly. It appears you have a fir or spruce tree. 

There are a number of pests, leaf blights and cankers that affect conifers (plants  that produce cones), especially as trees age.  If you want an exact diagnosis, which you would need to determine if the tree can be effectively treated in any way, there are a couple options.

First, you may submit sample branches that show still live and green needles, and include diseased  and dead needles on them. A totally dead branch can not give a dependable diagnosis. Samples can be submitted to MSU Diagnostic lab. The fee is about $20. Forms, fee schedule, and instructions are here---

https://pestid.msu.edu

Second, you may contact a certified arborist to come out and give a complete assessment of the trees, including a tree health care and treatment plan, if the trees are salvageable. Call a couple to get estimates. I understand this is a modestly priced service, especially when considering the value of your trees. You want an arborist, not just a tree service.

Search for them in your phone book or by zip code here--- www.treesaregood.org

If you are interested, here are references for you. As you will see, there are many possible diseases and insect pests on spruces. Firs tend to be more hardy but can have many of the same problems when stressed.

First- this shows how to tell pines, firs, and spruces apart---

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

Next, the most common spruce problems---

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

And some common insects---

https://extension.entm.purdue.edu/publications/E-256/E-256.pdf

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

I hope this information is of some help. Thank you.