# Can cutting down several trees make the earth spin faster? **URL:** \ **Category:** Factual Questions\ **Created:** [April 8, 2003, 9:22pm UTC](https://boards.straightdope.com/t/can-cutting-down-several-trees-make-the-earth-spin-faster/167399 "2003-04-08T21:22:33Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![gypsymoth3](https://avatars.discourse-cdn.com/v4/letter/g/85e7bf/32.png) [@gypsymoth3](https://boards.straightdope.com/u/gypsymoth3)\ **Post date:** [April 8, 2003, 9:22pm UTC](https://boards.straightdope.com/t/can-cutting-down-several-trees-make-the-earth-spin-faster/167399/1 "2003-04-08T21:22:33Z")
according to a not-so-serious website called [Brain of Brian](http://www.brainofbrian.com/philosophies2.html#6), " The earth may spin faster on its axis due to deforestation. Just as a figure skater’s rate of spin increases when the arms are brought in close to the body, the cutting of tall trees may cause our planet to spin dangerously fast. " so, let’s say, if 1/3 of all the world’s trees were cut down (assuming they weren’t replaced immediately by new ones), would the world spin 1 1/2 times as fast or any faster at all than it does now? ---
**Author:** ![x-ray\_vision](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/x-ray_vision/32/351_2.png) [@x-ray\_vision](https://boards.straightdope.com/u/x-ray_vision)\ **Post date:** [April 8, 2003, 9:28pm UTC](https://boards.straightdope.com/t/can-cutting-down-several-trees-make-the-earth-spin-faster/167399/2 "2003-04-08T21:28:25Z")
Think about the length and weight of one’s arms as compared to ones body and now think about the length and weight of even millions of trees as compared to the size and weight of the Earth. ---
**Author:** ![robby](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/robby/32/11048_2.png) [@robby](https://boards.straightdope.com/u/robby)\ **Post date:** [April 8, 2003, 9:29pm UTC](https://boards.straightdope.com/t/can-cutting-down-several-trees-make-the-earth-spin-faster/167399/3 "2003-04-08T21:29:08Z")
Theoretically, yes, the Earth would rotate faster on its axis. However, the increase would not be measurable. ---
**Author:** ![Q.E.D](https://avatars.discourse-cdn.com/v4/letter/q/51bf81/32.png) [@Q.E.D](https://boards.straightdope.com/u/Q.E.D)\ **Post date:** [April 8, 2003, 9:29pm UTC](https://boards.straightdope.com/t/can-cutting-down-several-trees-make-the-earth-spin-faster/167399/4 "2003-04-08T21:29:35Z")
You could cut down ALL the trees and it wouldn’t make much difference. Nothing measurable, at any rate. The skater can spin significantly faster because she is bringing a comparitively large percentage of her mass much closer to her center of mass. The mass of the trees is neglibigle compared to the mass of the Earth, and the decrease in diameter is likewise insignificant. ---
**Author:** ![Achernar](https://avatars.discourse-cdn.com/v4/letter/a/e274bd/32.png) [@Achernar](https://boards.straightdope.com/u/Achernar)\ **Post date:** [April 8, 2003, 9:39pm UTC](https://boards.straightdope.com/t/can-cutting-down-several-trees-make-the-earth-spin-faster/167399/5 "2003-04-08T21:39:46Z")
Hot diggity dog! I just happen to have done this calculation! Here’s the relevant thread: [Figure skaters increase spin rpm by pulling in their arms. How ? [May 2000]](http://boards.straightdope.com/sdmb/showthread.php?s=&threadid=25240) and here’s my post: [http://boards.straightdope.com/sdmb/showthread.php?s=&postid=473040#post473040](http://boards.straightdope.com/sdmb/showthread.php?s=&postid=473040#post473040) > [@](#): > > I computed how much the Earth’s rotation would be affected by, say, the felling of 10,000,000 Giant Sequoias at the Equator (where it would make the most difference). Anyway, I had to make up a couple of numbers, but the answer I got states that if some psychopathic logger were to pull off this feat, days would become a whopping 0.036 nanoseconds shorter. ---
**Author:** ![Munch](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/munch/32/5281_2.png) [@Munch](https://boards.straightdope.com/u/Munch)\ **Post date:** [April 8, 2003, 9:59pm UTC](https://boards.straightdope.com/t/can-cutting-down-several-trees-make-the-earth-spin-faster/167399/6 "2003-04-08T21:59:03Z")
[Ralph Wiggum] What’s a nanosecond? [/Ralph] But seriously, a nanosecond is what, .000000001 second? ---
**Author:** ![CC](https://avatars.discourse-cdn.com/v4/letter/c/f1d935/32.png) [@CC](https://boards.straightdope.com/u/CC)\ **Post date:** [April 8, 2003, 10:14pm UTC](https://boards.straightdope.com/t/can-cutting-down-several-trees-make-the-earth-spin-faster/167399/7 "2003-04-08T22:14:30Z")
On behalf of the many Dopers, I am grateful that Archernar does not have a life. ---
**Author:** ![Squink](https://avatars.discourse-cdn.com/v4/letter/s/b5e925/32.png) [@Squink](https://boards.straightdope.com/u/Squink)\ **Post date:** [April 8, 2003, 10:24pm UTC](https://boards.straightdope.com/t/can-cutting-down-several-trees-make-the-earth-spin-faster/167399/8 "2003-04-08T22:24:39Z")
[Wind](http://www.aer.com/scienceResearch/windblows.html) and [wintry weather](http://www.jpl.nasa.gov/earth/features/longdays.html) can cause the earth to spin faster or slower. > [@](#): > > On February 3rd, 1983, during an especially strong El Nino event, the > day was 3.4 milliseconds longer than normal. The effect of cutting down trees would likely be less noticable. ---
**Author:** ![aeropl](https://avatars.discourse-cdn.com/v4/letter/a/f05b48/32.png) [@aeropl](https://boards.straightdope.com/u/aeropl)\ **Post date:** [April 8, 2003, 10:34pm UTC](https://boards.straightdope.com/t/can-cutting-down-several-trees-make-the-earth-spin-faster/167399/9 "2003-04-08T22:34:27Z")
If the earth were to be scaled down to be six feet tall, even the world’s tallest tree (~367 ft. tall) would come out to be about .000631 inches tall in that scale… So you can imagine how little effect it would have, even given the numbers of them. ---
**Author:** ![kanicbird](https://avatars.discourse-cdn.com/v4/letter/k/5f8ce5/32.png) [@kanicbird](https://boards.straightdope.com/u/kanicbird)\ **Post date:** [April 8, 2003, 10:52pm UTC](https://boards.straightdope.com/t/can-cutting-down-several-trees-make-the-earth-spin-faster/167399/10 "2003-04-08T22:52:48Z")
Yes it would, but damming up rivers slowes the rotation ---
**Author:** ![panamajack](https://avatars.discourse-cdn.com/v4/letter/p/47e85d/32.png) [@panamajack](https://boards.straightdope.com/u/panamajack)\ **Post date:** [April 8, 2003, 11:43pm UTC](https://boards.straightdope.com/t/can-cutting-down-several-trees-make-the-earth-spin-faster/167399/11 "2003-04-08T23:43:11Z")
In response to **Munch** , yes, a nanosecond is 1x10[sup]-9[/sup] ( 0.000000001 sec). A light-nanosecond is very close to a foot. If 10 million trees is 36 picoseconds, I’d bet the daily speed-up due to simple erosion of mountain peaks must be on the order of a few femtoseconds (10[sup]-15[/sup] s) at least. I wonder by how much one Krakatoa slows us down? ---
**Author:** ![rexnervous](https://avatars.discourse-cdn.com/v4/letter/r/e9c0ed/32.png) [@rexnervous](https://boards.straightdope.com/u/rexnervous)\ **Post date:** [April 8, 2003, 11:51pm UTC](https://boards.straightdope.com/t/can-cutting-down-several-trees-make-the-earth-spin-faster/167399/12 "2003-04-08T23:51:37Z")
> [@](#): > > \*Originally posted by Squink \* > \*\*[Wind](http://www.aer.com/scienceResearch/windblows.html) and [wintry weather](http://www.jpl.nasa.gov/earth/features/longdays.html) can cause the earth to spin faster or slower. > The effect of cutting down trees would likely be less noticable. \*\* Yes, but what if a gale-force wintry wind _blew over all those trees_!!! :eek: :eek: ---
**Author:** ![Achernar](https://avatars.discourse-cdn.com/v4/letter/a/e274bd/32.png) [@Achernar](https://boards.straightdope.com/u/Achernar)\ **Post date:** [April 8, 2003, 11:53pm UTC](https://boards.straightdope.com/t/can-cutting-down-several-trees-make-the-earth-spin-faster/167399/13 "2003-04-08T23:53:23Z")
> [@](#): > > \*Originally posted by CC \* > On behalf of the many Dopers, I am grateful that Archernar does not have a life. Why thank y… hey!! Now that was almost three years ago. Who says I don’t have a life _now_? 😛 ---
**Author:** ![threephi](https://avatars.discourse-cdn.com/v4/letter/t/85f322/32.png) [@threephi](https://boards.straightdope.com/u/threephi)\ **Post date:** [April 9, 2003, 12:17am UTC](https://boards.straightdope.com/t/can-cutting-down-several-trees-make-the-earth-spin-faster/167399/14 "2003-04-09T00:17:59Z")
> [@](#): > > \*Originally posted by Squink \* > \*\*[Wind](http://www.aer.com/scienceResearch/windblows.html) and [wintry weather](http://www.jpl.nasa.gov/earth/features/longdays.html) can cause the earth to spin faster or slower. > The effect of cutting down trees would likely be less noticable. \*\* This discussion brings up an interesting side issue, [Leap Seconds](http://tycho.usno.navy.mil/leapsec.html). In a nutshell, as a result of tidal friction, the Earth’s rotation has historically been getting steadily slower (by about 1.4 milliseconds per day per century), when you compare “planetary” time with atomic measurement. Leap seconds have recently come about once every few years although the last one was on New Years 1999. It’s interesting to note also that the rate of leap seconds has slowed significantly of late, as can be seen [here](http://hpiers.obspm.fr/eop-pc/earthor/utc/leapsecond.html). Maybe cutting down all those trees **does** have a measurable effect! Although you’d have to factor in mining and high-rise construction/demolition as well… ---
**Author:** ![GuanoLad](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/guanolad/32/42_2.png) [@GuanoLad](https://boards.straightdope.com/u/GuanoLad)\ **Post date:** [April 9, 2003, 12:43am UTC](https://boards.straightdope.com/t/can-cutting-down-several-trees-make-the-earth-spin-faster/167399/15 "2003-04-09T00:43:43Z")
Wouldn’t anything within certain levels of the atmosphere have absolutely no effect on the spin of the earth? I always imagined the atmosphere to be sort of a protective shell for most things of this ilk. ---
**Author:** ![Donovan](https://avatars.discourse-cdn.com/v4/letter/d/ea666f/32.png) [@Donovan](https://boards.straightdope.com/u/Donovan)\ **Post date:** [April 9, 2003, 4:14am UTC](https://boards.straightdope.com/t/can-cutting-down-several-trees-make-the-earth-spin-faster/167399/16 "2003-04-09T04:14:36Z")
On a related note, how would all of the man made structures affect the rotational spin? Think of all of the TV and radio masts, skyscrapers, duplexes, etc (Even ‘short’ structures like houses are generally 15’ - 20’ tall)… wouldn’t we be creating a net decrease in rotational speed? There may not be as many structures built as trees removed, but AFAIK, the farther something is moved out from the axis, the more profound effect it will have on rotational speed, and many of our structures dwarf any tree. ---
**Author:** ![Quercus](https://avatars.discourse-cdn.com/v4/letter/q/7ab992/32.png) [@Quercus](https://boards.straightdope.com/u/Quercus)\ **Post date:** [April 9, 2003, 1:46pm UTC](https://boards.straightdope.com/t/can-cutting-down-several-trees-make-the-earth-spin-faster/167399/17 "2003-04-09T13:46:18Z")
Well, let’s just say that in theory, moving mass closer to the earth’s center will increase the rate of spin, and cutting down a tree so most of it sits closer to the ground is indeed moving its net mass closer to the ground; you could even calculate this effect, but you’d need a decimal point followed by a whole lot of zeros to write down how much the planet’s spin was increased. And it would probably turn out to be less than the effect of a good rainstorm (which is also moving mass [water] closer to the center; less mass than a forest, but much more distance). In other words, in theory, there’s an effect, but in practice, an effect so small that its ridiculous. ---
**Author:** ![CookingWithGas](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/cookingwithgas/32/485_2.png) [@CookingWithGas](https://boards.straightdope.com/u/CookingWithGas)\ **Post date:** [April 9, 2003, 1:49pm UTC](https://boards.straightdope.com/t/can-cutting-down-several-trees-make-the-earth-spin-faster/167399/18 "2003-04-09T13:49:05Z")
Now, now–this board has a longstanding culture of discussing effects that are so small that they’re ridiculous! 🙂 ---
**Author:** ![DMark](https://avatars.discourse-cdn.com/v4/letter/d/e68b1a/32.png) [@DMark](https://boards.straightdope.com/u/DMark)\ **Post date:** [April 9, 2003, 4:33pm UTC](https://boards.straightdope.com/t/can-cutting-down-several-trees-make-the-earth-spin-faster/167399/19 "2003-04-09T16:33:51Z")
Can cutting down several trees make the earth spin faster? Yes, just as removing a hair from your arm will allow you to run faster! ---
**Author:** ![UncleBeer](https://avatars.discourse-cdn.com/v4/letter/u/977dab/32.png) [@UncleBeer](https://boards.straightdope.com/u/UncleBeer)\ **Post date:** [April 9, 2003, 4:45pm UTC](https://boards.straightdope.com/t/can-cutting-down-several-trees-make-the-earth-spin-faster/167399/20 "2003-04-09T16:45:48Z")
I’ve merged the two threads to consolidate the comments (and deleted the posts referring to the now gone thread). If the conversation seems a bit disjointed (more so than is the usual case around here) that’s likely the reason. [Next page](https://boards.straightdope.com/t/can-cutting-down-several-trees-make-the-earth-spin-faster/167399.md?page=2)