Giant trees have no trouble pumping water to top branches: new research
157 points
by hhs
7 hours ago
| 11 comments
| news.exeter.ac.uk
| HN
karim79
2 hours ago
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I grow marijuana and chillies from time to time. I got good at it. I will say that plants are malleable in untold ways and so I find this article to be unsurprising.

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.

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kuerbel
36 minutes ago
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I'm studying for a bachelor's degree in horticulture part-time through a distance-learning university. If you're more interested in growing plants, I'd say horticulture is a better fit than botany. If you're more interested in understanding how plants work, botany is probably the better choice. That said, you'll still learn a lot of botany in a horticulture degree as well obviously
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karim79
1 minute ago
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Thank you sir. I actually got my CS from distance learning and somehow the combination of growing things and monitoring everything using CS just grabs me. I would work on any farm anywhere with appropriate agency.
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mountainriver
1 hour ago
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With a lot of software getting eaten up I’m increasingly interested in biology. Seems like one of the later frontiers that could have massive benefits, and AI is really well suited to help us understand it.
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karim79
51 minutes ago
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True and also, the actual physical contact and results are absolute magic. Maybe we need to create a "computer scientists for botony" forum. I think that has legs.

Botany is great because the results are basically what I'd call magic. It's such beauty (and horror on occasion).

The marriage of CS and botany seems like a match made in heaven and just from writing these comments I've convinced myself that it's probably the most practical way to go forward in life.

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grantith
27 minutes ago
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Just about everything we experience in our lives is a constant distraction from the fact that biology and its mechanisms are the most interesting thing in our existence.
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karim79
14 minutes ago
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Absolutely this.
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card_zero
1 hour ago
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There is apparently such a thing as "Computational Botany", where you model virtual plants.
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globular-toast
38 minutes ago
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Have you considered computational biology? They are always looking for people. Knuth said a while back that biology has tons of open and useful problems left to be solved.
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chasil
4 hours ago
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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

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calibas
5 hours ago
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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.

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Alien1Being
4 hours ago
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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"."

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fsckboy
4 hours ago
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>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".

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mattgrice
3 hours ago
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Yeah man if a barbarian fells a tree in the forest but nobody is around to hear it, is it still barbaric?
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vlovich123
3 hours ago
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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.
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card_zero
3 hours ago
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Yeah, they were called barbarians because they talked funny. Bar bar barbar bar, they went.
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alchemism
1 hour ago
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...and if you aren't pronouncing it "Var" you might be one ;-)
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GroksBarnacles
49 minutes ago
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This is such a useless comment. What even is your point?
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hinkley
5 hours ago
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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.

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ryanmcbride
5 hours ago
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God that's sad. We really can't have anything nice.
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hinkley
5 hours ago
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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.
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card_zero
3 hours ago
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Who wants moss!? Is it luxury moss?
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hinkley
57 minutes ago
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When peeled off the trunk it comes off in sheets, which is a bit harder to accomplish than just creating tufts and blobs of moss.
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lazide
2 hours ago
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Yes, for terrariums
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nomel
6 hours ago
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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...

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fc417fc802
3 hours ago
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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.
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oersted
2 hours ago
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Sounds cool but for such experimentation you would want relatively fast experimental iterations to get anywhere, and this would take literal ages. You can play around with growth speed of course but that’s a different question and might be in some ways opposed to achieving height.
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fc417fc802
1 hour ago
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I don't think so. You don't have to reach the height limit just to iteratively develop the initial implementation of the pump system. A system that actively moves water would push it out the top so you've got an observable phenomenon to work with.
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oersted
1 hour ago
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I’m sure there will be a ton of unexpected complexities that arise only when you are trying to push the limits, like in all engineering domains. And it’s all a highly interconnected system, you cannot expect to dramatically change the water flow without impacting others aspects.

I know it is quite distant, but from my experience in large-scale data engineering, 90% of the time goes in addressing subtle issues that can only be observed hours into a job, the rest of the issues are quickly resolved earlier. I am assuming that such complexities will be so much harder in physical systems, and even more so in biological systems.

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Sharlin
3 hours ago
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There are obviously other factors limiting tree growth, like compressive strength.
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ghaff
1 hour ago
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I seem to recall for some long-ago course that the 8,000m peaks are up around the compresssive limit so yoou couldn't really have a taller mountain.
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Jweb_Guru
5 minutes ago
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Mostly true on Earth, but not on other planets with lower gravity, and AFAIK it depends on the rock type. Hence why you have Olympus Mons on Mars (or insanely tall ice mountains on Pluto, when that material couldn't form such a steep talus angle on Earth).
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fc417fc802
2 hours ago
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Which would also serve as reasonable challenges for genetic and molecularbiological engineering so ... what's your point?

Or do you mean to suggest that the failure of any accepted tree height records to surpass the maximum capillary distance can be explained by some other factor? (Based on your other comment it seems safe to assume that isn't what you meant but anyhow.) That seems far too convenient given that the observed cutoff is within the expected range.

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gre
2 hours ago
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> 500m

500ft is taller than the max ever, not 1640 ft

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cortesoft
2 hours ago
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Couldn't both things be true? Water transport is not the limiting factor, but some other thing is?
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nullorempty
6 hours ago
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>Giant trees have no trouble pumping water to top branches

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

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leni536
6 hours ago
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What would you call it?
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cj
6 hours ago
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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”.
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chowells
6 hours ago
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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.

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pulvinar
5 hours ago
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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.

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hinkley
5 hours ago
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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.

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fc417fc802
3 hours ago
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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.

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left-struck
4 hours ago
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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.

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

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

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theendisney
3 hours ago
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This line of reasoning has always cracked me up. The internal dialog acidentally out loud at the least flattering moment. I believe the correct response to be:

The tree is a perpetual motion machine hooked up directly to the wheelworks of nature! It PUMPS 500 liters per day usibg Wind, solar, capilar action and evaporation! How do i charge my car with this?

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lazide
2 hours ago
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Well, if you chop it down and burn it to boil water, then Use it to spin up a turbine…
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taneq
1 hour ago
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It’s like the pop sci fact that if you took all your blood vessels and laid them end to end… you would die.
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fc417fc802
3 hours ago
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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.
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Sharlin
3 hours ago
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There are no pumps in a tree, in series or not. There’s nothing between the roots and leaves that actively drives water upward in any way. The xylem is literally dead tissue.
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fc417fc802
2 hours ago
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Please notice that the comment I was responding to there made claims of physical infeasibility that I was responding to. I was not expressing any claims regarding actual concrete trees that you could go and visit.

More generally you seem to be dismissing out of hand the primary topic of discussion which is neither constructive nor enlightening.

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kijin
4 hours ago
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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.
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margalabargala
6 hours ago
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Yeah it's the difference between creating low vs high pressure.
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card_zero
6 hours ago
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The low pressure is up there already, for free.

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

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rolph
6 hours ago
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card_zero
5 hours ago
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Oh, so we don't really know how it works. Fun.
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rolph
5 hours ago
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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.

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fc417fc802
3 hours ago
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> a transpiration stream, that ultimately ejects water vapour from the leaves

I don't believe this is correct, or rather is not a required component of the system but rather incidental. The chemical system within the leaf removes water via chemical reaction. There is a respiration process to dispose of waste gasses. Water vapor happens to be lost to this process not of necessity but rather because keeping it separate is quite difficult (ie requires significant complexity and additional energy expenditure). I expect that many desert adapted species approach perfection (but have not bothered to verify).

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gitaarik
6 hours ago
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“Trees contain lots of thin, hollow vessels and they suck water upwards by creating low pressure at the top,”

So sucking / pulling?

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IsTom
6 hours ago
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So a suction pump?
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card_zero
6 hours ago
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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.

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gitaarik
6 hours ago
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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?
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DANmode
6 hours ago
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Or, it’s simply a rate to variably adjust to, so the tree is neither flooding nor parching the leaf.
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hinkley
5 hours ago
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My recollection is that capillary action is a little from column a and a little from column b.
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m463
5 hours ago
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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

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efskap
5 hours ago
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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.
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c22
5 hours ago
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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.

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kijin
4 hours ago
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Actually, all matter is just trapped energy.
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theendisney
3 hours ago
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There is no such thing as energy.
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lazide
2 hours ago
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Rather, no such thing as matter. Energy is pervasive.
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kulahan
4 hours ago
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It's also kind of weird to think that soil, really, is just ground up "stuff" that used to be trees, plants, rocks, etc.
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nomel
5 hours ago
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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...

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hinkley
5 hours ago
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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.
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pkghost
4 hours ago
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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)

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theendisney
3 hours ago
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I regretably didnt save it but there was a truly hilarious topic on usenet sci.physics long long ago. If we've gathered enough evidence against something or if the thing goes against accepted consensus you are forbidden from doing further research and new evidence is no longer allowed. The topic then invited others to list such topics. The list grew to hundreds of entries and people couldnt resist getting angry reading their personal trigger words despite there being many more silly things on it.

Yours shall be filed under homeopathy :)

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fc417fc802
2 hours ago
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Be careful with that dismissal. The concept of an exclusion zone itself appears to be legitimate. More generally, there's lots of strange and surprising effects that crop up on the molecular level at interfaces in solution. However not all mechanistic explanations for such behavior are shall we say "widely accepted".

And then there's homeopathy which is a largely unrelated and entirely nonsensical thing.

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cwmoore
1 hour ago
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“The root cause is nailed down (not a theory anymore)…” —Claude
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jzer0cool
2 hours ago
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Any truth to whether water pumped by tree (branches) is potable?
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luxuryballs
1 hour ago
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I’m glad to find the trees are doing well, even the big ones, that managed to grow big... ???
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alldayhaterdude
6 hours ago
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Happy for them.
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lukeholder
5 hours ago
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This made me laugh out loud. Thanks.
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