# Trees and gravity **URL:** \ **Category:** Factual Questions\ **Created:** [March 25, 2006, 1:44am UTC](https://boards.straightdope.com/t/trees-and-gravity/349817 "2006-03-25T01:44:16Z")\ **Posts on this page:** 10\ **Page:** 2
**Author:** ![jjakucyk](https://avatars.discourse-cdn.com/v4/letter/j/3d9bf3/32.png) [@jjakucyk](https://boards.straightdope.com/u/jjakucyk)\ **Post date:** [April 5, 2023, 1:10pm UTC](https://boards.straightdope.com/t/trees-and-gravity/349817/21 "2023-04-05T13:10:39Z")
If there was no limit to the height water could travel in a tree, would trees actually get much taller? The tallest trees we have now require decades if not centuries to grow robust enough trunks to support themselves and brace against the wind. ---
**Author:** ![zimaane](https://avatars.discourse-cdn.com/v4/letter/z/a3d4f5/32.png) [@zimaane](https://boards.straightdope.com/u/zimaane)\ **Post date:** [April 5, 2023, 1:17pm UTC](https://boards.straightdope.com/t/trees-and-gravity/349817/22 "2023-04-05T13:17:17Z")
There’s a big advantage to being the tallest tree in the forest, as you get unfettered access to sunlight. ---
**Author:** ![Crafter\_Man](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/crafter_man/32/458_2.png) [@Crafter\_Man](https://boards.straightdope.com/u/Crafter_Man)\ **Post date:** [April 5, 2023, 1:44pm UTC](https://boards.straightdope.com/t/trees-and-gravity/349817/23 "2023-04-05T13:44:09Z")
> [@Limmin](#): > > isn’t a siphon mechanism based on the same negative pressure idea? IANAP, but I do not believe a siphon works using the negative pressure (tension) principle. It works simply with air pressure. If you pull a vacuum, you can pull water up to a maximum height of around 33 feet at the Earth’s surface. ---
**Author:** ![Crafter\_Man](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/crafter_man/32/458_2.png) [@Crafter\_Man](https://boards.straightdope.com/u/Crafter_Man)\ **Post date:** [April 5, 2023, 1:46pm UTC](https://boards.straightdope.com/t/trees-and-gravity/349817/24 "2023-04-05T13:46:43Z")
> [@zimaane](#): > > There’s a big advantage to being the tallest tree in the forest, as you get unfettered access to sunlight. _There is unrest in the forest_ _There is trouble with the trees_ _For the maples want more sunlight_ _And the oaks ignore their pleas_ — N. Peart ---
**Author:** ![jjakucyk](https://avatars.discourse-cdn.com/v4/letter/j/3d9bf3/32.png) [@jjakucyk](https://boards.straightdope.com/u/jjakucyk)\ **Post date:** [April 5, 2023, 6:38pm UTC](https://boards.straightdope.com/t/trees-and-gravity/349817/25 "2023-04-05T18:38:53Z")
> [@zimaane](#): > > There’s a big advantage to being the tallest tree in the forest, as you get unfettered access to sunlight. Sure, but again it requires more “structure” to get up to that height where the tree is more vulnerable to wind, lightning, and gravity. Aside from the giant redwoods that need massive trunks to support their height, the crazy tall spindly palm trees that you see around Los Angeles sacrifice their lower leaves to be able to extend their trunks to that height. Granted most palms do that as a matter of course, but not to grow quite that high up. ---
**Author:** ![Great\_Antibob](https://avatars.discourse-cdn.com/v4/letter/g/e47c2d/32.png) [@Great\_Antibob](https://boards.straightdope.com/u/Great_Antibob)\ **Post date:** [April 5, 2023, 7:44pm UTC](https://boards.straightdope.com/t/trees-and-gravity/349817/26 "2023-04-05T19:44:45Z")
There are other impediments to extreme tree height - wind was mentioned but also cold. Grow too tall and other mechanisms become required to deal with exposure to wind and low temperature. Basically, what happens at the tree line in more mountainous areas. ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [April 5, 2023, 8:59pm UTC](https://boards.straightdope.com/t/trees-and-gravity/349817/27 "2023-04-05T20:59:52Z")
A siphon depends on the water column not breaking apart. There are two effects that prevent the column from breaking apart, cohesion of the water itself, and atmospheric pressure. Under ordinary conditions, with a tube of diameter, say, 1 cm, the effect from atmospheric pressure is much, much stronger than that from cohesion, and so a siphon in vacuum could only lift water a very slight distance, and a siphon on Earth can only lift water slightly further than the air-pressure-column-height of about 10 meters. But trees are much taller than that, so that clearly can’t be the full explanation. Does something about the tree’s tubes being so much narrower, make the cohesion effect greater? ---
**Author:** ![Lucas\_Jackson](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lucas_jackson/32/303_2.png) [@Lucas\_Jackson](https://boards.straightdope.com/u/Lucas_Jackson)\ **Post date:** [April 6, 2023, 4:13pm UTC](https://boards.straightdope.com/t/trees-and-gravity/349817/28 "2023-04-06T16:13:42Z")
In architecture school we were taught that a column of concrete (porous material) is capable of wicking water large distances due to capillary suction. We were taught 2 miles high. [However, this article claims 6 miles.](https://buildingscience.com/documents/insights/bsi-011-capillarity-small-sacrifices#:~:text=The%20theoretical%20limit%20of%20capillary,kilometers%20or%20about%206%20miles.) For wood it claims 400 feet. From the article: _“In wood it is about 400 feet—the height limit trees can grow to is set by the size of the capillary pores in wood. Ever wonder how leaves get water? When you go into a forest and listen very carefully you don’t hear any pumps pumping water upwards a couple of hundred feet do you? Capillary suction is powerful stuff. When you add salt to the water the power becomes explosive”_ ---
**Author:** ![Crafter\_Man](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/crafter_man/32/458_2.png) [@Crafter\_Man](https://boards.straightdope.com/u/Crafter_Man)\ **Post date:** [April 6, 2023, 5:20pm UTC](https://boards.straightdope.com/t/trees-and-gravity/349817/29 "2023-04-06T17:20:24Z")
According to the [video](https://www.youtube.com/watch?v=BickMFHAZR0&t=129s) linked above, the xylem tubes (in the tree that transport water) are too wide for capillary action to take place. Is he incorrect? ---
**Author:** ![TriPolar](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tripolar/32/3008_2.png) [@TriPolar](https://boards.straightdope.com/u/TriPolar)\ **Post date:** [April 6, 2023, 5:33pm UTC](https://boards.straightdope.com/t/trees-and-gravity/349817/30 "2023-04-06T17:33:51Z")
He says that they are too wide to raise water more than 1 meter under atmospheric pressure. He then explains that atmospheric pressure is not the consideration because the tree has achieved great negative liquid pressure internally. [Previous page](https://boards.straightdope.com/t/trees-and-gravity/349817.md?page=1)