Fatih,
IMO I would be careful about trying to fertilize them too soon. I would let them have a chance to develop some first.
For the Sycamore, remember what Darrell said
Platanus occidentalis should germinate if sown on the surface of moist soil in a warm place. You could also try them rolled up in a moist paper towel in a bag, then check them for germination every few days. Pluck out and pot up those that begin to germinate. Platanus occidentalis may have a majority of empty seeds.
For burr oak Darrell said 60 to 90 days cold moist stratification at 1-3 degrees celsius ( 32-38 degrees F )
Bill
Last edited by Bill D.; 01/02/15 04:33 PM.