i think whats important also, is if the water is moving or stagnant,
and also how old the tree is.
Older larger roots have had time to change the soil around their roots,
since the roots send out exudates...
The biology changes the soil structure (near the root) over time.
This can help stave off several issues including flooding.
Moving water brings O2 to the roots
and takes away CO2 and toxins. (this is why Hydroponics works)
So.... if it keeps raining for several days,
its better, than if it just stagnant water.
It is obviously species and age specific though.