Evergreen Tree Trouble: Loosing more needles than normalEvergreen Tree Trouble: Loosing more needles than normal

I have several large evergreen trees in my yard, not sure what kind exactly. This year I noticed they are dropping more needels than I would think is typical. I've included some pictures, can anyone suggest what might be causing this? I don't want to loose these trees. There hasn't been a huge drought or rainfall. There are some moles I believe in this area and some fungus at times on the ground.

Any suggestions is apprecieated.