Tom Bennett wrote:
snip
:: However, I've also known of cases where movement of soil *after* a
:: large well-established tree/shrub has been removed (and the soil
:: then suddenly becomes more saturated where it has previously been
:: largely dry) has caused expansion and movement of the foundations,
:: where none had occurred when the tree was still there.

This is more likely to be the roots rotting away and leaving voids IME.