What causes trees to grow upward?

[Shadowscape]

Before you say, light, I live in the far north of Minnesota, and some of you live further north than that. Our trees would be growing toward the south if that were the case. And a tree seed buried in the dirt doesn't see any light, and yet it grows upward. And once out in the light and heat, they still continue basically straight upward.
Is it a gravity fighting thing built into plants?
Food for thought.

 

[AdkEric]

Geotropism would be my thought.

 

[Boomslang]

Probably spite. Gravity says "whoa there". Tree says "hold my beer"

 

[Shadowscape]

Geotropism would be my thought.

I agree, but it would be pretty neat to know how that actually works in plants. As far as I know, and I know very little, there is no central system controlling the growth cells of the plant that tell them to fight gravity by growing oppositely.
Maybe there is and we just don't know that yet. Plants never cease to amaze me.

 

[Lignotuber]

I agree, but it would be pretty neat to know how that actually works in plants. As far as I know, and I know very little, there is no central system controlling the growth cells of the plant that tell them to fight gravity by growing oppositely.
Maybe there is and we just don't know that yet. Plants never cease to amaze me.

Fun fact, there's a tree cook pine (Araucaria columnaris) that has a sweeping bend/tilt towards the equator like 91% of the time.

 

[Shadowscape]

Fun fact, there's a tree cook pine (Araucaria columnaris) that has a sweeping bend/tilt towards the equator like 91% of the time.

That's cool. That I'm guessing is light caused. I'll have to look that one up.

 

[data farm 26]

Apical dominance and light competition come to mind, that'd be the how I guess. Why, I think I've read about supposedly there are reproductive and survival advantages to being tall. The central control system is the genetics imo. I think growing at an angle towards the sun would be more like fighting gravity vs growing straight up is more like working with gravity to me.

 

[Shadowscape]

@L3VI
When a tree gets bent over and held in that horizontal position, the new growth will make a 90 degree turn to go upward. There has to be some mechanism that tells the cells to do that turn. And a question I will be seeking out today, because it just came to mind is, Are the cells on the outside of that turn longer than the cells on the inside, or, are there more cells on the outside of the turn than on the inside? One of those scenarios needs to be true, and there must be some communication to those cells to perform that task, and from what source? There is more to this than I understand.

 

[surveyor]

We had a downed tree on our lot that then grew a line of trees along its stem.

In SA there was a small fern that, if touched, would fold up its leaflets and even the branch would droop, then later would perk back up and unfold.

 

[Shadowscape]

We had a downed tree on our lot that then grew a line of trees along its stem.

In SA there was a small fern that, if touched, would fold up its leaflets and even the branch would droop, then later would perk back up and unfold.

Really make you wonder. Does me anyway.
I'm sure biologists can tell you about what the plants do, but can they tell you what is going on between cells in that plant that transmits the information needed to make that happen?
I'm going to be contacting the University of Wisconsin Forest Extension Service today with some questions. I trust them more than my home state people or the U.S. Forest Circus to have better answers.
Something to do on a cold winter day... Still a cold winter day here.

 

[Njdelaney]

My bet is that growing straight upwards provides the highest probability of not touching anything else or encountering any obstacles.

 

[Rusticus]

Shaded cells do grow longer, in some species. That's why the edge effect in a forest talks about trees leaning out away from the rest of the canopy cover having more growth on the shaded sides to cause the lean. Bamboo staked trees in nurseries will have longer elongation on that one side too, if left too long. It is only part of the answer though.

 

[Shadowscape]

My bet is that growing straight upwards provides the highest probability of not touching anything else or encountering any obstacles.

True. My question though is, What causes it to do so? What is the mechanics involved it making it go up? There has got to be some communication between the wood cells and ????? Do wood cells have the ability on their own to naturally grow against gravity? If so, what is involved with that? Or are they just worker bees that do what they are told?
I am probably overly consumed with this, but there should be answers that we don't yet know about.
So far, my research has lead me to believe the biologists are about in the dark as I am. They are just telling me the wood cells just do that without an explanation as to why, other than they need height and light. That sounds to me like they don't get it either. We already know that much. But does a wood cell know that? I doubt it.

 

[Shadowscape]

Shaded cells do grow longer, in some species. That's why the edge effect in a forest talks about trees leaning out away from the rest of the canopy cover having more growth on the shaded sides to cause the lean. Bamboo staked trees in nurseries will have longer elongation on that one side too, if left too long. It is only part of the answer though.

This morning I also received that answer. Thank you. The cells are longer on the outside of a bend. And less sun/heat causes them to grow longer. I can wrap my brain around that notion.
In terms of needing to grow upward, I can only assume they are engineered to grow against gravity. I have found no one who is in a position to say that with any creditable knowledge in the bio/wood industry as of yet. They are all very cautious about choosing their words so as not to be guessing.
I will probably never be satisfied, so I should drop it and move on.
Watching the eagles feed a newly hatched eaglet out my window today. I know where there is a roadkill deer close by, so I will probably drag that home for them later on this afternoon. Lake is still frozen over with a couple of feet of ice, so pickings will be slim for them for another couple of weeks.

 

[cerviarborist]

Gravitropism. It's what makes trunks go up and roots go down.

 

[Shadowscape]

I don't see any great mystery here but maybe I'm not understanding the question.

Trees growing directly opposite to the force of gravity were, for various reasons, more successful in survival and reproduction. So the apical dominance became part of the plan.

Trees have to do extra work in putting on more wood in the tension or compression plane depending on species so it would only make sense to continue the upward habit (a less energy intensive way to stack cells) after it has been partially knocked over or bent.

"this old world keeps spinnin round,
It's a wonder tall trees ain't layin down."
Neil Young (or shadowscape after a really long winter )

But how?
I understand what you are saying.
Let me put it this way:
Take one single wood cell. Forget the entire rest of the tree. It is a long and thin cell. It is simple in design with its outer shell and inner space, which contains water and minerals. There is no brain or nervous system. No muscles. And yet, it fights to grow against gravity all the time. How? You might as well take a paper straw, pinch one end closed, fill it with water, pinch that end closed, then lay it down on the kitchen table. When you come home tonight and find it standing up on end you just write it off as "Gravitropism"? I know what that is. How does that cell know what that is, and what causes it to take that action?
We all know how trees grow and what it is called. I want to know how a wood cell knows what it is suppose to be doing.
So far, the university forestry extension programs I have contacted tell me they don't know either. Which tells me that there is a lot we don't understand about plants yet.

Maybe it just has been a long winter.....

 

[data farm 26]

Idk I think its above my pay grade, that's all I've got.

 

[kludge]

The Wikipedia article on gravitropism describes a mechanism called statoliths and their affect on auxin.

 

[oldoakman]

I agree, but it would be pretty neat to know how that actually works in plants. As far as I know, and I know very little, there is no central system controlling the growth cells of the plant that tell them to fight gravity by growing oppositely.
Maybe there is and we just don't know that yet. Plants never cease to amaze me.

Just about anything on this brown and blue ball we ride on never ceases to amaze me.

 

[Treetopflyer]

Gravitropism. It's what makes trunks go up and roots go down.

Thanks for the link