A bed of pine needles can happen to be one of the hardest terrain where you have to track.
Seek all the disturbances you can find in it and analyze each one. Search for little amount of material can mean finding the result of a push forward of a toe, for example. More significantly, you can find even a slide, due to the slippery nature of the terrain.
Ask yourself: Is that caused by a human or an animal?
Try to replicate what you see by your own.
Always: “Index early, index often”
(Rob Speiden quote)