|MadSci Network: Botany|
Trees do not need to grow straight to conduct water. Woody vines do it effectively and can be very contorted. The path of water is not through a single tube, but through a series of xylem elements. In nearly all trees these elements are not arranged in a strictly vertical pattern but are offset from one another giving rise to a spiral pattern of water flow. The water flows largely due to suction from above, not due to capillary flow. Often times the cohesive strand of water will break, Recent research suggests that these breaks may be repaired overnight when the plant is under less water stress, for if the breaks were not repaired, tall trees would die due to lack of water. Check a good plant physiology book for more details on this.
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