This video raises some interesting questions. How does water get up to the top of a tree?

"evaporation creates a negative water vapor pressure in the surrounding cells of the leaf...water is pulled into the leaf from the vascular tissue, the xylem, to replace the water that has transpired from the leaf. This pulling of water...will extend all the way down...into the xylem of the roots due to the cohesive forces holding together the water molecules along the sides of the xylem tubing...The loss of water from a leaf (negative water pressure, or a vacuum) is comparable to placing suction to the end of a straw. If the vacuum or suction thus created is great enough, water will rise up through the straw. If you had a very large diameter straw, you would need more suction to lift the water. Likewise, if you had a very narrow straw, less suction would be required. This correlation occurs as a result of the cohesive nature of water along the sides of the straw (the sides of the xylem). Because of the narrow diameter of the xylem tubing, the degree of water tension, (vacuum) required to drive water up through the xylem can be easily attained through normal transpiration rates.

"The xylem is also composed of elongated cells. Once the cells are formed, they die. But the cell walls still remain intact, and serve as an excellent pipeline to transport water from the roots to the leaves...All xylem cells that carry water are dead, so they act as a pipe. Xylem tissue is found in all growth rings (wood) of the tree. Not all tree species have the same number of annual growth rings that are active in the movement of water and mineral nutrients. For example, conifer trees and some hardwood species may have several growth rings that are active conductors, whereas in other species, such as the oaks, only the current years' growth ring is functional...It's amazing that a 200 year-old living oak tree can survive and grow using only the support of a very thin layer of tissue beneath the bark. The rest of the 199 growth rings are mostly inactive. 
https://www.scientificamerican.com/article/how-do-large-trees-such-a/?redirect=1

4:29 Why do trees transport so much water if they only use 5% of what they transport? 
The leaves have to have openings to let CO2 in, which also allows water to escape by evaporation, and leaves have to remain moist to transport nutrients and sugars, so the price they pay for survival is to transpire huge amounts of water they never use. 
"To make sugars, plants must absorb CO2 from the atmosphere through small pores in their leaves called stomata. However, when stomata open, water is lost to the atmosphere at a prolific rate relative to the small amount of CO2 absorbed; across plant species an average of 400 water molecules are lost for each CO2 molecule gained. The balance between transpiration and photosynthesis forms an essential compromise in the existence of plants; stomata must remain open to build sugars but risk dehydration in the process...The amount of water lost via transpiration can be incredibly high; a single irrigated corn plant growing in Kansas can use 200 L of water during a typical summer, while some large rainforest trees can use nearly 1200 L of water in a single day!"
https://www.nature.com/scitable/knowledge/library/water-uptake-and-transport-in-vascular-plants-103016037

 Why does an air pocket not kill the tree?
"Water moving through plants is considered meta-stable because at a certain point the water column breaks when tension becomes excessive — a phenomenon referred to as cavitation. After cavitation occurs, a gas bubble (i.e., embolism) can form and fill the conduit, effectively blocking water movement. Both sub-zero temperatures and drought can cause embolisms...An air seed creates a void in the water...Failure to re-establish flow in embolized conduits reduces hydraulic capacity, limits photosynthesis, and results in plant death in extreme cases. Plants can cope with emboli by diverting water around blockages via pits connecting adjacent functional conduits, and by growing new xylem to replace lost hydraulic capacity. Some plants possess the ability to repair breaks in the water columns...Brodersen et al. (2010) recently visualized and quantified the refilling process in live grapevines using...a type of CAT scan...Successful vessel refilling was dependent on water influx from living cells surrounding the xylem conduits, where individual water droplets expanded over time, filled vessels, and forced the dissolution of entrapped gas.
https://www.nature.com/scitable/knowledge/library/water-uptake-and-transport-in-vascular-plants-103016037