Looks like someone slashed the tree with a sword that dealt fire damage.Imagine finding this out of nowhere and it starts calling your name in a smoothing voice.This happened to an old oak near the park I live next to. It was very old, very dead already and was pretty hollow already from carpenter ants. The lightning hit and the fire burned inside it and was shooting out of the tips of all the old branches! It was both horrifying and also one of the coolest things I've ever seen!