Direct seeded LOTS of trees last year. Some were seeded just by walking through the woods, finding a spot and pushing a nut in the ground. Others were planned out, cleared around and tubed. I planted White Oaks, Bur Oaks, Swamp Chestnut Oaks, Sawtooth Oaks and Three Chestnut varities.
I will say that on the tubed seeds I have nearly 100% success rate with two exceptions... In one area in particular, I must have an educated squirrel, he has figured out how to go under the tube enough to move it out of the way and steal the nut (replanted that spot 4 times now). And the other bust was a creek bottom that flooded and pretty much wiped out all the swamp chestnut oaks I had planted there. Many had sprouted before the flood but I don't think they were established enough to be underwater for a couple of weeks.
For the seeds that I just dropped in the ground while walking through the woods I have not been able to find a single surviving tree. I'm not sure if squirrels got them or if something browsed them.... Or, I may just not be seeing them.... The same exact seed stock in tubes are a foot tall.
One thing I did as a backup plan... I had lots of nuts leftover, so in my garden I planted a few rows of trees. They did pretty well and I will use them to re-plant any un-successful field plantings this winter.
Others have already said this, but white oaks go straight from collection into the ground, everything else got cold stratified in the fridge for me.