I might be reading in favour of my watering habits

but what I did understand had me thinking the tree uses more water during the day, that one I think is simple. And Uses more oxegen through the night so wetter during the day moistish during the night.
I think there is some in there how even though the tree shuts down in the heat it still uses alot of water?
Although I don't know some of these words here.
Good soil is hypotonic (more water less solutes)
Good root tip cells are hypertonic (less water more solutes)
Water diffuses from a hypotonic to a hypertonic solution
This happens day and night
Plants do not have a pump
Their water is drawn from roots to shoots by capillarity
Capillarity is greatest when plants are loosing water from shoots
This happens day and night
I guess ash is getting at that the salt content of the tree must be higher than the substrate to suck up the water. If it is the other way around the substrate sucks water from the tree. That spells death.
It's a very cool bunch of what seem to be valid facts

It's too bad your in such a hurry cause the stories I could tell you, Bushels and baskets of stories, hole crates full of stories. But if you can spare a moment I will tell you one story.