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Hacker News Hacker NewsThis sentence undersells the phenomenon quite a bit: the “extreme low pressure” is in fact several bars of negative pressure and the challenge of maintaining water in liquid form is avoiding cavitation.
I was exposed to the physics of trees though the entrance exam to École Polytechnique (France's best University) and it's been carved in my mind since then: http://alainrobichon.free.fr/Concours/X_PC_PH1_01.pdf
AFAIK students are still being given this masterpiece for practice even though it's now 25 years old.
Plants will do what they need to do in the end. I've done stuff like co2 bombing, and increasing nutrients to the point to where I get a whole new ecosystem of insects and an entirely new situation.
It is such fascinating stuff that it's actually the life I want to live. I'm a computer scientist but now I yearn for the botanical sciences.
I highly recommend checking out defoliation strategies and low-stress training methods for anyone interested. Plants are not dumb creatures. The results you can get from them are astonishing and the science of what plants actually are becomes more profound by the day.
[1] https://www.sfgate.com/science/article/REDWOODS-How-tall-can...
A bucket brigade works just as well up ten flights of stairs as up one hundred. So does a system of opening and closing valves.
We can pump water from a bucket on one floor of building to a bucket on the next floor easily. Then we can repeat the same thing at the next floor; the pressure from the numerous floors above doesn't factor in because there isn't a connected water column.
Too bad we cut it down, along with almost every other giant Douglas-fir.
Hm, may be because they are not really "pumping" the water?
Coalescence of coastal fog accounts for a considerable part of the trees' water needs.[23]
https://en.wikipedia.org/wiki/Sequoia_sempervirens#Fog_and_f...
While admittedly contested and only reproduced by a few labs outside Gerald Pollack's at University of Washington, there is a solid case that it could play a role in transporting water and sap to the tops of trees. At least, it's involved in the motion induced in hydrophilic tubes when there is sufficient ambient radiant energy (uv/infrared).
Relevant papers:
"Exclusion-zone water inside and outside of plant xylem vessels." 2024 Scientific Reports. https://www.nature.com/articles/s41598-024-62983-3
"Surface-induced flow: a natural microscopic engine using infrared energy as fuel." 202 Science Advances. https://www.science.org/doi/10.1126/sciadv.aba0941
"Long-range forces extending from polymer-gel surfaces." 2003 Phys. Rev. E. https://link.aps.org/doi/10.1103/PhysRevE.68.031408
Pollack's site: https://www.pollacklab.org/
Some critiques of Pollack's theory:
Schurr, J.M. (2013). Phenomena associated with gel–water interfaces: analyses and alternatives to the long-range ordered water hypothesis. J. Phys. Chem. B, 117(25), 7653–7674. https://doi.org/10.1021/jp302589y Elton, D.C., Spencer, P.D., Riches, J.D. & Williams, E.D. (2020). Exclusion zone phenomena in water — a critical review of experimental findings and theories. Int. J. Mol. Sci., 21(14), 5041. https://doi.org/10.3390/ijms21145041 (open access; the most thorough critical review) Elton, D.C. & Spencer, P.D. (2021). Pathological water science — four examples and what they have in common. In Water in Biomechanical and Related Systems (Biologically-Inspired Systems, vol. 17), pp. 155–170. Springer. https://doi.org/10.1007/978-3-030-67227-0_8 (preprint: https://arxiv.org/abs/2010.07287)
It seems that trees just don't grow that tall anymore. Even common trees such as the spruce seem to be able to reach 100m, they just kind of don't.
One possibility is the depletion of nutrients. But what I think is to blame is the lack of elephants. They constantly ruined young trees and the lucky few that survived then grew huge. Perhaps the redwoods were actually created by the natives, who removed young trees, and kept the old trees standing.