Giant trees have no trouble pumping water to top branches: new research

Mechanism of Water Transport (Pumping vs Sucking)

• Several comments stress that trees do not “pump” water like a mechanical pump; they mainly “draw” it via low pressure at the top.
• The cohesion–tension model and capillary action are repeatedly cited: evaporation in leaves creates tension, pulling a continuous water column up xylem vessels.
• It’s noted that xylem is dead tissue, with no active pumps or valves, contradicting ideas of “pumps in series.”
• Some push back on oversimplified popular explanations, reminding that a simple suction column in open air cannot lift water beyond ~10 m; capillaries and negative pressure change that picture.
• There is mention of trees operating at several bars of negative pressure and the challenge of avoiding cavitation.

Height Limits and Gravity

• Skeptics argue the new research conflicts with earlier work showing strong limits on maximum height (~130 m) from water transport and gravity.
• Others suggest water transport might not be the sole limiting factor; mechanical strength of wood and other constraints are also invoked.
• Speculative ideas appear: different evolutionary pressures (e.g., megafauna damaging saplings, human activity, nutrient depletion) might explain why trees are not taller today; these are presented as conjecture, not established fact.

Alternative Water Sources and Adaptations

• Fog capture in coastal redwoods and possible mutualism with moss (holding moisture on branches) are discussed as ways to supplement water, especially at height.
• Leaves and moss absorbing water directly from rain or fog is seen as a way to bypass long-distance transport for some needs.
• Desert and evergreen adaptations (e.g., reduced transpiration, CAM photosynthesis) are mentioned as strategies to manage water loss.

Structured / Exclusion-Zone Water Debate

• One line of discussion introduces “structured water” or exclusion-zone (EZ) water as a possible contributor to sap flow driven by radiant energy.
• Others respond cautiously, noting that while interfacial water phenomena are real, specific EZ claims are contested and subject to critical reviews.

Attitudes Toward the Research and Plant Science

• Some dismiss the paper as confirming the obvious (big trees clearly get water to their tops), but acknowledge that incremental, non-controversial work is common.
• Multiple commenters express strong interest in botany, plant physiology, and computational/technical approaches to agriculture, framing plant biology as a major frontier.