Harvest as much apple leaves/ branches and twigs as you can! Ir dries wonderfully...I usually dry loads and store in cardboard boxes in my loft for winter forage...great to add to hay even when dried for a something interesting to eat.
I limit mine when fresh...only cause my one bun gets an upset tummy...but depends how oyur buns re-act...if poops fine and they eating good formed ceacals..then any amount is fine. I find when dried I can give unlimited as its not so rish for them.
The branches are GREAT for them to gnaw and keeps their teeth down...
above applies to willow too...
but dont give unlimited...if they tend to eat loads of willow it can be a sign of pain...willow has a natural pain killer in it...but again...leabes, branches all fine