Autumn Blaze Maple disease
Does anyone know what this is ????
Central Norfolk UK
and welcome to the forum 😊
That looks like rot.
How long has the tree been planted there?
Has the soil level around the tree been changed at any time?
“I am not lost, for I know where I am. But however, where I am may be lost.”
Winnie the Pooh
That looks nasty, so sorry to see a Maple like that!
Looking around the net I see water logged roots as a possible cause. Dig around the Maple to see what’s happening to the root system.