It's only natural to be worried when you see your beautiful evergreens turning brown in the center and needles scattered on the ground. Rest assured, this is just yearly needle shedding, called Fall Needle Drop. Even evergreens can't hold onto all their leaves forever. The older needles, near the interior of the tree, eventually give out. Be patient. There will be new growth next season.
However, look carefully. If more than the inner needles are browning, it could be a totally different problem and you don't want it to get out of hand.
Photo: © Marie Iannotti