I've seen allot of people pile their leaves right next to their tree trunk's in stead of composting them or mowing them,don't these people know that this will kill their trees?
Come on everybody ,leaves go in the compost pile

I've been piling leaves under my trees for 20 years. Why would it kill the tree? Are you talking about piling the leaves up against the bark? Then that would be a problem.

Come late fall when the grass no longer needs mowing is when I leave it to the leaves. It may get a high run over around Christmas to clean it up. Those leaves go in the compost.

About this time of year, the live oak is pushing off old leaves and I bag some for the garden as mulch. The rest get chopped into the yard. Works great.