Pinon pine trees, I think, Onebyone! I once stopped with a friend on the way back from N.Mexico to AZ and came across a bunch of Pinon pine trees in full fruit! We spent time picking them up, then *forever* getting the nuts out, picking them from the shell and roasting them. Then, forever removing the pine tar from everything, ha! I love pine nut pesto though!
Good to know about the garlic, I've hesitated to make fresh pesto just because of this 'burn' factor. I love the sharpness of fresh garlic, but it doesn't love me!