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).
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)
"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"."
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".
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.
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.
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”.
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.
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.
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.
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.
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.
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?
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.
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.
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)
Too bad we cut it down, along with almost every other giant Douglas-fir.
"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"."
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".
For a while there were people poaching the moss that facilitated this, which is a problem because it grows only inches per year.
https://m.youtube.com/watch?v=ZSch_NgZpQs
https://m.youtube.com/watch?v=pHJIhxZEoxg
[1] https://www.sfgate.com/science/article/REDWOODS-How-tall-can...
Hm, may be because they are not really "pumping" the water?
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.
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.
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.
... that would be the least of the tree's problems.
Or the high pressure is down here, whichever way you want to look at it.
https://en.wikipedia.org/wiki/Xylem#Cohesion-tension_theory
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.
So sucking / pulling?
> 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.
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
Weirder still is the realization that all the air is just trapped light.
[1] https://www.sfgate.com/science/article/REDWOODS-How-tall-can...