Yep. I remember on of my grandfather's notes from a December 24th talked of concertina wire and AT/AP mines.

Maj Todd O. USMC, Retired
Grandson of LTC John O'Brien
Certainly happiness could not be much, far from home and loved ones and under enemy fire.
But I find that there is a great sense of family in that Christmas tree and in that sign.
Even doing something like that is a sign of great humanity in my opinion ...
For some it will be a horrible Christmas and for some a bit better ... Rocky in fact does not remember anything about that picture, he had already passed beyond....
Grandson of Private Pedro Pedrini, 14th Infantry Regiment, "Pinerolo" Brigade.
Transferred to 3rd Regiment Telegraph Engineer During WW I