>Giant trees have no trouble pumping water to top branches Hm, may be because they are not really "pumping" the water?
What would you call it?
more like capillary action.
Giant trees have no trouble pumping water to top branches: new research
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Re: Giant trees have no trouble pumping water to top branches: new research
#12Earlier quoted context omitted.
So a suction pump?
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.
Or, it’s simply a rate to variably adjust to, so the tree is neither flooding nor parching the leaf.
Re: Giant trees have no trouble pumping water to top branches: new research
#13Earlier quoted context omitted.
So a suction pump?
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.
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?
Re: Giant trees have no trouble pumping water to top branches: new research
#14This 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...
Re: Giant trees have no trouble pumping water to top branches: new research
#15Earlier quoted context omitted.
What would you call it?
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.
Re: Giant trees have no trouble pumping water to top branches: new research
#16on 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...
Re: Giant trees have no trouble pumping water to top branches: new research
#17Happy for them.
This made me laugh out loud. Thanks.
Re: Giant trees have no trouble pumping water to top branches: new research
#18Re: Giant trees have no trouble pumping water to top branches: new research
#19on 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
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...
Re: Giant trees have no trouble pumping water to top branches: new research
#20Earlier 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.…
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.