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tehuti88
06-24-2008, 06:10 PM
All right...I do hope I'm putting this in the right place! *blush*

This is more for curiosity's sake, but it would be interesting if I could make it at least semi-realistic for a future story. So while I realize it's doubtful I'll get any scientific answers to something so scientifically impossible, I'd appreciate educated guesses, at least.

The basic premise: In the traditional Ojibwa (Chippewa) worldview, there was an immense white cedar known as the Great Medicine Tree and this thing was so tall that it spanned through the "four realms"--the underworld, the earth we live upon, the sky, and the "sky vault" (which I would assume is the atmosphere, where it ends right before space, however that goes...*is ignorant*). The very top of the tree pokes through the "sky vault" to let in light. Meaning, this is one hugely immense gargantuan tree.

I'm mulling over including this tree in a future story. While there are plenty of fantastic liberties taken (I mean, just think about the idea of this tree and you'll see what I mean...in my story, thunderstorms are caused by giant birds hunting lake serpents, see?), I wondered just how big such a tree would be if it were real.

So...anyone have any idea? It's a white cedar, if that makes any difference. How many miles high would this thing be (from the ground up...I'm guessing there's no way to know how long/deep the roots are?), and, what I'm more interested in knowing, how wide across (diameter) would the trunk be? Is this something that, if you were right next to it, you wouldn't be able to see anything ahead of you but trunk, endlessly from left to right? Would you be able to see any of the branches (immense, to match the tree's height) so high above or would it all be lost in haze? *is curious*

I realize I can just make it all up to suit my story, but I still wanted to know, if possible.

zenwriter
06-24-2008, 06:30 PM
The biggest trees are giant sequoias, and there is one (or used to be one) in California that is over 80 metres high, with a circumference of 30 meters (at the base of the trunk). Eastern White Pines generally grow between 50 and 55 meters and Western White Pines Can grow 30-70 m tall.

Hope this helps.

auntybug
06-24-2008, 06:36 PM
There's a baynan tree (http://www.hawaiiweb.com/maui/html/sites/banyan_tree.html) in Lahaina on Maui that spans a whole block. Not sure if that would help... it has several "trunks" - its just what came to mind when I saw the title.

Sarpedon
06-24-2008, 06:49 PM
the trouble with very large things is that their weight increases with the cube of their size, while their area increases only as a square.

So that means that if you double the size of a tree, its weight increases 8 times, (2x2x2) but the area of its trunk, on which depends its ability to stand, only increases 4 times (2x2).

Then there's the fact that wind loads increase dramatically above 60 feet or so.

So what would a huge tree look like? Well, its trunk would be enormously wide compared to what we expect from a tree. Its trunk would be hollow, to save weight, and it probably wouldn't have too many leaves, to reduce wind loads.

So, in other words, a huge tree would look like a cactus.

tehuti88
06-25-2008, 12:33 AM
Hm, I'm not sure if I was clear... *blush*

Firstly, I'm not asking about the world's largest trees which really exist...I'm asking about a mythological tree, as if it were in existence.

Secondly, I realize the physical impossibilities of such a tree, so things such as its weight, or how the wind or elements would affect it, don't come into play. The story is mythological, so there's a suspension of disbelief in that there is simply a giant white cedar stretching from the earth to the sky vault. I assume it looks basically like any other white cedar, just really really big. (Not merely tall, but wide to match--imagining that its circumference and height are in the same proportions as an average white cedar, just increased.) Due to it being the "Great Medicine Tree" (a supernatural being), its weight isn't a problem, the hole it pokes through the sky vault isn't ruining the atmosphere or anything, etc.

I was just curious to know how many miles high, for example, this thing would be, if its branches would be visible from the earth's surface, and how great would be the diameter of its trunk if this were physically possible (again, suspending disbelief).

Recall this obviously isn't scientifically based. *blushing again*

tehuti88
06-25-2008, 12:53 AM
I just realized something! My question is more speculative (fantasy/mythology) in nature and I've posted it here, in the research-type forum. I was going to post it in the Science Fact item as that's in the Fantasy area, but saw that that was all for, well, science fact, so I thought this was the appropriate place. Was I in fact incorrect? I notice that most questions here are looking for more factual-type answers whereas mine is speculative, even though I am interested in knowing how tall and wide the thing would be, scientifically speaking. Should I have posted to Fantasy instead? So sorry if I was wrong!

Sarpedon
06-25-2008, 01:19 AM
Oh, well if its a magic tree, then why ask the question. Its just a magic tree, you can make it as high as you want.

If the earth is round, it can't possibly be visible from everywhere on earth. If the earth is flat, then whether its visible or not depends on the distance and size. The human eye can resolve 1.6 arc minutes. So just figure out the distance, and you should be able to calculate how big it would have to be to be seen.

zenwriter
06-25-2008, 01:19 AM
I don't think it matters where you post, really -- you'll find AWers willing to help. You could post in the Fantasy section just to see if there is someone who knows something.

I know that many planes fly at 30 and 40 thousand feet and they are still sometimes visible on a clear day. Soo...if your tree had branches as big as a commercial plane, maybe it could be up that high and its branches would still be visible? I guess that would be one way to approach this question, although maybe there is someone here who knows more?

Sarpedon
06-25-2008, 01:28 AM
I went to college in milwaukee. On a clear day you could see the sears tower in Chicago across the lake.

Puma
06-25-2008, 01:45 AM
Don't know if this will make any difference, but (factually) the government has statistics on the largest trees of every type. A white cedar would not be as large as a sequoia - ever. Remember that in mythology, things were fanciful so this giant cedar would not have had enormous proportions when it was first imagined. It's very similar to the stories of the land being carried on a turtle's back - how big would the turtle have been. My opinion, when you write a story with ideas such as yours you should avoid dimensions like the plague. Puma

Polenth
06-25-2008, 01:55 AM
Going with a height of 100km (~62 miles), I'd guess the diameter of the trunk at about 5km (~3 miles). This is assuming I have the right white cedar. The one I'm thinking of is relatively thin compared to its height.

The 100km isn't exact, as there's no sharp divide between the atmosphere and space. But it seems like a fair distance to me. This Wiki article explains it:

http://en.wikipedia.org/wiki/K%C3%A1rm%C3%A1n_line

A tree that size would be a major worldbuilding thing. The canopy would block the stars and cast large shadows during the day. It'd be visible on clear days, but the clouds will block it on overcast days. You'd be able to see the trunk from a great distance.

RJK
06-26-2008, 10:09 PM
See if you can find a copy of Integral Trees by Larry Niven. These are trees that have evolved in space (how that's done is too complicated to describe here). Larry does an excellent job of describing what the environment would be like and how a whole culture of people live in a tree that measures its dimensions in miles.