@Fiona-Respha If by status you mean the message on the Tree when you go up to it, then you can tell what it is based on the maximum amount of water you can add to it is (I don't know the exact phrases that are used), even if the message doesn't update. If the maximum amount of water that can be added is less than 44,000, then it it at it's "healthiest", and from there it "health" goes down by every 4000, with no effect on the buffs that the tree has; however, if it becomes fully depleted (ie. it needs 60,000 to fill it), then the buffs will not be accessible until water is added.
If you mean the visual change from leveling the tree, then it will happen automatically once the tree's buffs total levels hit certain thresholds.