This happened back on Thursday, 14 April 2017, in Charles County.
What a crushing tragedy. And totally unnecessary. There's no excuse for having a child any where near the drop radius of a tree. If you can't or won't keep them (or anything else you care about) away from the tree you are felling, then you do not fell the tree. And you do not even start that chainsaw.
Let this sad event serve as a reminder to anyone that picks up a chainsaw: safety is paramount. There are too many ways to get injured when you are felling trees or even just using a dangerous tool like a chainsaw.
My deepest sympathies to the families involved.