We have a beautiful clump birch tree, just over 2 stories high. This morning I woke up with leaves all over our lawn, it seems like the small branches with approx. leaves have been either bitten off or broken off, the ones lying on the ground have a white web like fungus or something over them. Last year the tree was infested with stink bugs, not sure if this has anything to do with it.
I would hate to have to cut this tree down so I need some help.
Thanks

I forgot to add that the leaves have just recently come out and are a beautiful normal green colour. Ni disformation or discolouration.