Depends on the tree and type of water I assume
youtube.com/watch?v=twjPo2Luk5A
Mangrove trees live submerged in saltwater for example. This video also goes over some of the adaptations it has to do that (ex. Special roots to allow it to stand upright in soft unstable ground)
breakfastmtn@lemmy.ca 11 months ago
It would die. The roots need to do gas exchange too. Ideal soil composition is generally 45% mineral, ~25% water, ~25% air, and 5% organic matter.
Tree bark also does gas exchange.