I also used a nail clipper just to clip the bit it was attached to the parent tree to help speed up the germinating process but nothing seems to have worked...
First of all.. It just takes time. Expecting seedlings within a week or two is for pretty much all species unrealistic. Seeds are dormant and wait for optimal circumstances. I have sowed mine in November, and no activity above-ground yet. I do not want any till march anyway. With frost arriving again this week, I am pretty sure they stay in the ground till march now.
Clipping seeds is only for very specific species. The ones you mention do not need it. Worse, by clipping the seed you open it up for pathogens.