Daldinia concentrica apparently has several names including coal fungus or King Alfred’s cakes (which sounds a lot nicer than cramp balls, one of its other names). The fruiting bodies of a fungus, which in our wood as elsewhere seems to prefer ash.
It enjoys nothing more than a spot of chemoheterotrophic extracellular digestion on some dead wood. The flesh inside is is arranged in concentric layers representing ‘a season of reproduction’, whatever that means. Lots of insects make their home inside which might explain the hole, or it may just be where the spores were released.
Interesting factoid from woodlands.co.uk: the inner flesh, once dried out, can be easily lit by a spark and, although it burns slowly like a barbecue briquette, once it has been lit one can transfer the glowing part to a ball of tinder and get a flame started. Have a look at this YouTube video.