"Did he give any specifics on the type of needles?"
Not that I recall. I have the episode on my dvr so i'll go back and check.
I found this at Saveur:
(Terrée de Moules)
Pine needles impart a delicious, smoky tang to the mussels in a classic terrée de moules, or mussel bake, which is traditionally done on the beach. The same results (and spectacle) can be achieved by means of a standard kettle grill. If you have access to dried, pesticide-free longleaf pine needles (from a species like aleppo or umbrella), you can collect your own (make sure they're completely brown). Place 1 1?2 lbs. scrubbed and bearded mussels, rounded side up, about 1"–2" apart, between the slats of the grill grate. Pile lightly packed dried pine needles atop mussels to a height of about 12". Light needles with a match; stand back. Allow needles to burn to ash, about 4–5 minutes. Dust away excess ash. Eat the mussels straight from the grill. (Discard any that are unopened.) Serves 4.
This article was first published in Saveur in Issue #103