Giant trees have no trouble pumping water to top branches: new research • Hacker News Board

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

#41

Post by fsckboy » Sat, Jul 04, 2026, 1:43 AM UTC

Alien1Being wrote: post #36

calibas wrote: post #23

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.

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 o…

>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".

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

#42

Post by kijin » Sat, Jul 04, 2026, 1:45 AM UTC

chowells wrote: post #15

cj wrote: post #4

Earlier quoted context omitted.

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.…

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.

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

#43

Post by left-struck » Sat, Jul 04, 2026, 1:50 AM UTC

pulvinar wrote: post #20

chowells wrote: post #15

Earlier quoted context omitted.

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.…

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 i…

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.

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

#44

Post by vlovich123 » Sat, Jul 04, 2026, 1:58 AM UTC

fsckboy wrote: post #41

Alien1Being wrote: post #36

Earlier quoted context omitted.

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 o…

> 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".

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.

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

#45

Post by fc417fc802 » Sat, Jul 04, 2026, 2:10 AM UTC

nomel wrote: post #14

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...

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.

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

#46

Post by fc417fc802 » Sat, Jul 04, 2026, 2:13 AM UTC

chowells wrote: post #15

cj wrote: post #4

Earlier quoted context omitted.

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.…

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.

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

#47

Post by card_zero » Sat, Jul 04, 2026, 2:15 AM UTC

vlovich123 wrote: post #44

fsckboy wrote: post #41

Earlier quoted context omitted.

> 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".

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.

Yeah, they were called barbarians because they talked funny. Bar bar barbar bar, they went.

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

#48

Post by card_zero » Sat, Jul 04, 2026, 2:19 AM UTC

hinkley wrote: post #31

ryanmcbride wrote: post #27

Earlier quoted context omitted.

God that's sad. We really can't have anything nice.

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.

Who wants moss!? Is it luxury moss?

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

#49

Post by mattgrice » Sat, Jul 04, 2026, 2:22 AM UTC

fsckboy wrote: post #41

Alien1Being wrote: post #36

Earlier quoted context omitted.

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 o…

> 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".

Yeah man if a barbarian fells a tree in the forest but nobody is around to hear it, is it still barbaric?

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

#50

Post by fc417fc802 » Sat, Jul 04, 2026, 2:24 AM UTC

hinkley wrote: post #28

pulvinar wrote: post #20

Earlier quoted context omitted.

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 i…

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…

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.