What pressure is needed to move water from the soil to the t

What pressure is needed to move water from the soil to the top of an 80-meter tall tree?

If the tree above transpires 1000 liters of water a day, how many vessels are needed to get the water from the soil to the top of the tree. Assume that the only vessels you need to concern yourselves with are the ones in the trunk. You can assume that the height of the tree does not matter, as the xylem tissue is full of water at the start. You need to make some other assumptions to answer this question. State these assumptions.

Solution

Water moves up to xylem by capillary action and forming concave menisci inside the pores. Water pulling in the xylem is influenced by transpirational pull and net transpiration cause negative pressure that pulls water up. As the tree requires more water to compensate transpirational loss the diameter of the xylem cannot be increase but the number of these capillaries should be sufficient to allow passage of the required amount of water per time/ rate.
The tree needing 1000 liters of water a day require sufficient xylem vessels to allow flow of 1000 liters of water per 24 hours or 41.66 liter per hour. So the tree need much xylem to support this flow.