My father has a large magnolia tree in his garden which is too big. It's
about 20ft tall with a generous spread and is probably magnolia
soulangiana (it was already in the garden when he moved in). He would
like to drastically reduce it in size - preferably halve it - it's too
near the house and creates lots of shade. Does anyone know whether this
is advisable or will this kill the tree or completely ruin it's looks?
It currently flowers very profusely. Thanks for any advice.

Liz