Fortune does not work on leaves

I farmed jungle trees for a while and broke all leaves with a Fortune 3 axe, but the amount of saplings stayed almost stagnant, only increasing by 1 every few trees. Then I broke 248 jungle leaves in a test world with a Fortune 127 axe and got 30 saplings, as well as 62 oak leaves, giving 5 oak saplings. Sticks and apples are similarly rare. Either I have insanely bad luck or Fortune does not work on leaves.