Beavers write prayer for something on leaf, say it and can play the memory game similar to "I went to the shops and bought a..." i.e. as we go round the circle the list of things we're praying for grows longer, each child has to repeat the previously mentioned prayers and add on their own. Should sort the kids by age so the youngest don't have to remember too many!
Stick the leaves onto a big tree trunk : could be drawn on the board.
If this is very quick we can also do a prayer of thanks i.e. I am thankful for... and repeat the above.
leaves (ideally : sticky post it notes)
A tree trunk - drawn on board or made of paper and stuck up on the wall