I don't suppose they survive once it's well rotted. Pine needles inhibit germination but they don't bother established trees at all. The interesting thing is that in a generation, a new conifer plantation can completely change the soil type, from a fertile, neutral or alkaline brown earth (the sort of fertile lowland soil most of us are used to) into an infertile, acid podsol, simply through the effects of the acid from decaying needles.