This is about wood ash .. not the tree.
Wood ash is a highly valuable product of our wood burning stoves and cookers.
However the biggest thing to remember is to use it very sparingly .. consider how many logs go into creating a shovel full of ash, so its really concentrated and very powerful.
it is a rich source of potash
so can be used as a pasture conditioner
for feeding fruit trees
in compost toilets
for making soap
hen dust baths
keeping slugs off seedlings ?