So far, I've only gotten saplings when letting the leaves decay by themselves, with an average of 1 sapling per tree when I do that.
If I break the leaves myself (sickle, hand, chainsaw) I get no saplings.
As I mentioned before, you can indeed get them with the sickle, as I got several from a single tree once. The method I tended to get saplings more often from was using the Wand of Excavation on the leaves that was mentioned earlier in the thread, but that could just be a massive coincidence since getting the saplings at all is just a random pile of luck.
@War Even those numbers seem kinda low when compared to the massive amounts of silverwood trees in jungle hills back in 1.2.5. I used one seed and it ended up spawning about 15 trees in a 5x5 chunk grid. I don't expect to see that many with them dropping saplings now though, but hopefully I'll end up with a good age to grab some. Decided to restart on a different seed to refine my methods of starting a map and early production lines. So far it goes:
if spawn near village, secure the villagers by making sure they can enter/leave houses, surrounding the village with fences, destroy small houses that are out of the way, fill in holes, and eventually force villagers into stalls
Clear land for temporary house, build a fence around it, make some stone bricks to place my ladders on for tunneling
if day, gather farm animals and pen them in the chunks around my house for easy access
if night, dig underground if temporary base is built, if not hide in the nearby village since that's why it's not built yet
if in need of ingots, use slag furnace if pulverizor or induction furnace unavailable
On this iteration I managed to get lucky with a priest, blacksmith and butcher. The butcher will take all the raw steak I'll end up getting from slaughtering cows, the blacksmith's first trade is iirc 11-12 emeralds for a diamond sword, and the first two trades on the priest are an emerald for 3 glowstone and an emerald for 3 redstone. I also have some villagers that will take wheat, chicken, fish, and wool for emeralds. Hopefully one of them will get a trade for shears : /