Giant trees have no trouble pumping water to top branches

(exeter.ac.uk)

97 points | by hhs 3 hours ago

8 comments

  • calibas 2 hours ago
    The largest tree on record is rejected in part because it's over the theoretical limit: https://en.wikipedia.org/wiki/Nooksack_Giant

    Too bad we cut it down, along with almost every other giant Douglas-fir.

    • Alien1Being 1 hour ago
      Human barbarism is not new...

      "The placard recorded that the Nooksack tree produced 96,345 board feet (227.348 cubic meters) of the "finest quality" lumber.

      The New York Times regarded the tree in a March 7, 1897 issue as the "most magnificent fir tree ever beheld by human eyes" and called its destruction a "truly pitiable tale" and a "crime".

      The Morning Times of February 28, 1897 claimed that the wood, sawed into one-inch strips, would reach from "Whatcom [the tree's location] to China"."

      • fsckboy 45 minutes ago
        >Human barbarism is not new...

        to be fair, without humans there would be nobody to declare "barbarism". At one time, all humans were barbarians, it took a certain level of cultural development before the word "barbarism" was necessary, so at that point it was "new". It remains be be shown whether cultures that call other cultures "barbaric" are actually "better".

        • mattgrice 6 minutes ago
          Yeah man if a barbarian fells a tree in the forest but nobody is around to hear it, is it still barbaric?
        • vlovich123 30 minutes ago
          Barbarism was just the ethnic slang Greeks had for non Greeks that Romans then adopted for non Romans. But cultures playing “I’m the best” is not new nor did it require cultural development; othering is a natural part of game theory to make sure your tribe has tighter cohesion against intruders.
          • card_zero 13 minutes ago
            Yeah, they were called barbarians because they talked funny. Bar bar barbar bar, they went.
    • hinkley 2 hours ago
      There are stories that the moss on trees in temperate rainforests allow the tree to pull water from their branches instead of the ground, increasing their max height.

      For a while there were people poaching the moss that facilitated this, which is a problem because it grows only inches per year.

      • ryanmcbride 2 hours ago
        God that's sad. We really can't have anything nice.
        • hinkley 1 hour ago
          It’s harder to remove the moss from high up in the tree and there are more risks in doing so. I was never clear on how prevalent this shittery was.
          • card_zero 9 minutes ago
            Who wants moss!? Is it luxury moss?
  • chasil 1 hour ago
    Kurzgesagt has two videos on trees addressing this and other questions.

    https://m.youtube.com/watch?v=ZSch_NgZpQs

    https://m.youtube.com/watch?v=pHJIhxZEoxg

  • nomel 2 hours ago
    This goes against all previous research/measurements for actually tall trees (looks like they only considered up to 80m) and the fact that there are exactly zeros trees in the world taller than 130 meters [1]. Wide capillaries at the base, like stated in the article, don't seem to be related.

    [1] https://www.sfgate.com/science/article/REDWOODS-How-tall-can...

    • fc417fc802 18 minutes ago
      I agree it doesn't pass the sniff test (where are the 500 meter trees in the rainforests?) but I think it would make an excellent goal for molecularbiological and genetic engineering. We (our civilization) need to become much more skilled at that before we start editing the human germline, and we will inevitably want to edit the human germline eventually (or rather we are currently exhibiting great restraint in not doing so but I'm not sure how much longer that will last), and anyway thousand meter trees just sound like they would be really cool.
  • nullorempty 3 hours ago
    >Giant trees have no trouble pumping water to top branches

    Hm, may be because they are not really "pumping" the water?

    • leni536 3 hours ago
      What would you call it?
      • cj 2 hours ago
        Not that it really matters, but the article also refers to it as “drawing water to the top”. That seems more representative of reality than “pumping water from the bottom”.
        • chowells 2 hours ago
          If you think of it that way, you have a real problem. It only takes about 10 meters for the weight of a column of water to create enough downward force that it starts vaporizing, at which point no pumping action works. This is why any deep well has a submerged pump. You simply can't pull water upward further than that with negative pressure in the Earth's atmosphere. It must be pushed with positive pressure instead.

          This is why the question is interesting. You can't just suck water to the top of a 60 meter tree. There must be some kind of positive-pressure pumping involved.

          • pulvinar 2 hours ago
            The trick for trees is capillaries, which change the equation. The 10 meter limit only applies to larger columns. With capillaries there's a high negative tension that allows evaporation from leaves to pull the xylem sap up 100 meters or more.

            There's no free lunch here. The Sun drives the evaporation, and if the tree were in a closed system with no solar input, the humidity would eventually get high enough to stop it.

            • hinkley 2 hours ago
              One of the things Susan Simard proved was that deep rooted trees that had found subterranean water continue pulling that water at full speed at night when transpiration is low, and that water finds its way into the fungal networks in the soil and into nearby plants.

              Simard attributes intention to this, but osmosis is “fair”. It seeks to move water to where sugars are and sugars to where water is. So a plant giving up sugars will receive water, and one low on water will give up sugars in the process of equalization.

              Do fungi contain pumps to maintain disequilibrium in this work? I could not say. But even when they first learned the trick of tapping roots the basic premise would have worked in a rudimentary fashion woth no further optimization.

              • fc417fc802 4 minutes ago
                I don't understand how osmosis enters into this? Capillary action is sufficient to explain water traveling up the roots to a point where it was removed. Evaporation from leaves is sufficient to explain removal during the day. You'd need some other explanation for extraction by fungi or etc at night.

                As a largely unrelated aside, there will still be a chemical potential across a membrane that doesn't permit a solute to cross. So water can diffuse into a concentrated solution without the solute flowing backwards into the reservoir. Alternatively, small solutes can leave while larger solutes are retained. This is the basis of dialysis.

            • left-struck 38 minutes ago
              The 10 metre thing assumes you have a suction side which is 10 metres lower than the pump, or at least a suction that is long/low enough that it can’t meet the pump’s NPSHr (Net Positive Suction Head required).

              In a tree the inlet to the “pump” is at the base of the tree. It’s not like there’s a pump sitting in the tree at 80 metres trying to suck water up from the ground, that would obviously fail. It’s more like a very long pump.

            • tenuousemphasis 2 hours ago
              >if the tree were in a closed system with no solar input

              ... that would be the least of the tree's problems.

          • fc417fc802 14 minutes ago
            That analysis only applies to a single discreet pump. A line of pumps in series does not suffer from that problem and that is roughly what a biological system would be expected to consist of.
          • kijin 43 minutes ago
            Yeah, that "extreme low pressure" part of the article had me scratching my head. Even a complete vacuum at the top will not suck water up more than 10 meters! The author was probably oversimplifying for a lay audience.
        • margalabargala 2 hours ago
          Yeah it's the difference between creating low vs high pressure.
          • card_zero 2 hours ago
            The low pressure is up there already, for free.

            Or the high pressure is down here, whichever way you want to look at it.

      • rolph 2 hours ago
        • rolph 2 hours ago
          the research is relevant to the issue of transpiration column hieght as a postulated limitation to overall hieght of any tree.

          a column of water is pulled by hydrogen bonding between molecules in a tug of war fashion, the top of the column is where water is dissociated from the column at such a rate as to maintain low pressure with respect to the column[xylem]

          in summary water moves from bottom to top in a transpiration stream, that ultimately ejects water vapour from the leaves, resulting in a low efficiency mechanism, that loses a lot of the water but occurs at such a rate that the low efficiency is "good enough" for whats needed.

        • card_zero 2 hours ago
          Oh, so we don't really know how it works. Fun.
      • gitaarik 2 hours ago
        “Trees contain lots of thin, hollow vessels and they suck water upwards by creating low pressure at the top,”

        So sucking / pulling?

        • IsTom 2 hours ago
          So a suction pump?
          • card_zero 2 hours ago
            Same principle as chimneys. But I also noticed this line:

            > leaves which have adapted to withstand greater water stress before wilting.

            That must be one of the "adjustments to water transport" mentioned. So I suggest that they do, in fact, have trouble pumping water to top branches.

            • gitaarik 2 hours ago
              Maybe it's not more trouble pumping, eh, sucking water up. But that the top branches are the last ones to get water in periods of draught, and have therefore more resilience?
            • DANmode 2 hours ago
              Or, it’s simply a rate to variably adjust to, so the tree is neither flooding nor parching the leaf.
          • hinkley 1 hour ago
            My recollection is that capillary action is a little from column a and a little from column b.
  • m463 2 hours ago
    on the other hand, many giant trees get the water out of the air via fog:

    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...

    https://en.wikipedia.org/wiki/Sequoia_sempervirens

    • efskap 1 hour ago
      Similarly, it blows my mind that all trees are made of air, specifically the carbon in it. I used to think that the biomass must come from the soil, but reality is more interesting.
      • c22 1 hour ago
        Kind of like how the vast majority of weight loss in animals happens via exhaling.

        Weirder still is the realization that all the air is just trapped light.

        • kijin 48 minutes ago
          Actually, all matter is just trapped energy.
      • kulahan 52 minutes ago
        It's also kind of weird to think that soil, really, is just ground up "stuff" that used to be trees, plants, rocks, etc.
    • nomel 2 hours ago
      Sequoia are still limited in height by gravity, probably due to capillary pressures. [1] If they evolved to be segmented, they could probably do it.

      [1] https://www.sfgate.com/science/article/REDWOODS-How-tall-can...

    • hinkley 1 hour ago
      There’s also a theory that the moss on these trees is mutualism instead of simply epiphytic. The moss holds moisture, which can be accessed by the tree.
  • pkghost 47 minutes ago
    Folks still sleeping on structured water.

    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)

  • alldayhaterdude 2 hours ago
    Happy for them.
    • lukeholder 2 hours ago
      This made me laugh out loud. Thanks.
  • arghandugh 2 hours ago
    [dead]