I work for a landscaping company in the nursery & one of the Concolor
Fir's has needles turning brown & dropping. I've been googling it & so
far I've read that old needles will drop... These Fir's are about 12
ft tall if not a little taller & established in the ground. Is it a
safe bet that they're just old needles falling off? The older gal I
work with usually knows these kinds of things like the back of her
hand but she was somewhat confused by it as well. I'm hoping I can
give her an answer.

I appreciate the feedback.
Thanks!